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All Graduate Theses and Dissertations Graduate Studies
5-1969
Quality of Beef Roasts: Electronic Versus Conventional Cooking
Frances Glassett Taylor Utah State University
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Recommended Citation Taylor, Frances Glassett, "Quality of Beef Roasts: Electronic Versus Conventional Cooking" (1969). All Graduate Theses and Dissertations. 4850. https://digitalcommons.usu.edu/etd/4850
This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. QUALITY OF BEEF ROASTS: ELECTRONIC VERSUS
CONVENTIONAL COOKING
by
Frances Glassett Taylor
A thesis submitted in partial fulfillment of the requirements for the degree
of
MASTER OF SCIENCE
in
Food and Nutrition
UTAH STATE UNIVERSITY• Logan, Utah 1969 ii
ACKNOWLEDGMENT
The author wishes to express gratitude to those who have assisted
in making this project a reality. Sincere appreciation is expressed to Dr. Ethelwyn B, Wilcox for her kind understanding, help, and encouragement as a friend, advisor, and member of the committee.
Special appreciation is felt toward Mrs. Charlotte P. Brennand, who, as thesis director, offered valuable help and recommendations and toward Dr. James A. Bennett, member of the committee and taste panel, for his suggestions and for making the meat available through the
Department of Animal Science for the study.
The assistance of the taste panel members during the study is gratefully acknowledged. Dr. Donald B. Sisson and others in the
Applied Statistics Department willingly gave suggestions for design and helped in the statistical analysis. A deep feeling of love and appreciation is felt for the author's father and for her son and daughter, and their spouses, for their never-failing encouragement, consideration, and assistance without which this project would have been impossible. iii
TABLE OF CONTENTS
Page
INTRODUCTION. 1
REVIEWOF LITERATURE 3
Flavor components of meat 3 Factors influencing juiciness of beef 7 Factors influencing tenderness of beef 9 Effects of cooking method 20
METHODOF PROCEDURE 26
History of meat 26 Design of study 29
Arm roasts 29 Rib roasts 31
Sample preparation 33 Objective methods of evaluation 35 Sensory method of evaluation 38 Statistical methods 38
RESULTS AND DISCUSSION 39
Arm roasts . 39
Objective measurements 39 Cooking losses . 44 Sensory evaluations 46
Rib roasts . t.9
Objective measurements 49 Cooking losses . 55 Sensory evaluations 62
Effect of bone 66 Correlations 71
Ann roasts 71 Rib roasts 73
COMMENTSAND CONCLUSIONS 78 iv
TABLE OF CONTENTS(Continued)
Page
SUMMARY. 82
LITERATURECITED 84
APPENDICES 92
Appendix A. Tables 93 Appendix B. Score card for beef 102 Adjectives used for scoring beef 103
VITA. 104 v
LIST OF TABLES
Table Page
1. Composition of feed pellets 27
2. Mean weights of rib and arm roasts 27
3. Experimental design for cooking adjacent arm roasts 30
4. Experimental design for cooking number 2 rib roasts 32
5. Mean scores and standard errors of objective measure- men ts for arm roasts 40
6 . Mean scores of cooking loss measurements for ann roasts 45
7. Time required for cooking arm roasts by four methods 46
8 . Mean scores for flavor, juiciness and tenderness of arm roasts as judged by taste panel 47
9. Mean scores and standard errors of objective and sensory evaluations for number 1 rib roasts 53
10 . Mean scores of objective measurements for number 2 rib roasts 56
11. Means for backfat thickness, roast size, cooking time, and cooking losses for number 1 rib roasts 60
12. Mean scores of cooking losses for number 2 rib roasts 61
13. Mean scores of sensory measurements for number 2 rib roasts 64
14. Analysis of variance for number 2 rib roasts due to oven, bone, and oven x bone inter action. 65
15. Correla tio n coefficients for sensory and objective tests, total cooking loss, age, and backfat thi ckness for arm roasts 72
16. Correlation coefficients for sensory and objective t ests, total cooking loss, age, and backfat thickness for number 1 rib roasts 74 vi
LIST OF TABLES (Continued)
Table Page
17. Correlation coefficients for sensory and objective tests, total cooking loss, age, and backfat thickness for number 2 rib roasts 76
18. History of animals 93
19. Individual data for arm roasts 95
20. Individual data for number 1 rib roasts 98
21. Individual data for number rib roasts 100 vii
LIST OF FIGURES
Figure Page
1. Diagram of carcass showing location of rib and arm roasts 28
2. Diagram of succulometer used for press fluid determinations (from Stembridge, 1968) 37
3. Range of Warner-Bratzler shear values for tenderness as a result of methods of cooking arm roasts (lower value indicates more tenderness) 41
4. Range of press fluid values as a result of methods of cooking arm roasts 43
5. Range of senso ry evaluation scores for flavor as a result of methods of cooking arm roasts 48
6. Range of sensory evaluation scores for juiciness as a result of methods of cooking arm roasts 50
7. Range of sensory evaluation scores for tenderness as a result of methods of cook ing arm roasts 51
8. Range of Warner-Bratzler shear values for tenderness as a result of methods of cook ing number 2 rib roasts 57
9. Range of press fluid values as a result of methods of cooking number 2 rib roasts 58
10. Number 2 rib roast cooked conventionally at 325 F to an internal temperature of 155 F 63
11. Number 2 rib roast cooked electronically to an internal temperature of 140 F 63
12. Range of sensory evaluation scores for flavor as a result of methods of cooking number 2 rib roasts 67
13. Range of sensory evaluation scores for juiciness as a result of methods of cooking number 2 rib roasts 68
14. Range of sensory evaluation scores for tenderness as a result of methods of cooking number 2 rib roasts 69
15. Per cent of moisture loss from meat adjacent to the bone . 70 viii
ABSTRACT
Quality of Beef Roasts: Electronic
Versus Conventional Cooking
by
Frances G. Taylor, Master of Science
Utah State University, 1969
Major Professor: Dr. Ethelwyn B. Wilcox Thesis Director: Charlotte P. Brennand Department: Food and Nutrition
The effect of breed, backfat thickness, and methods of cooking on quality of beef roasts was determined by sensory and objective methods.
Arm and rib roasts from Hereford, Shorthorn, Charolais, and Shorthorn-
Charolais animals were cooked by several methods.
Roasts of the ninth to twelfth ribs were all dry roasted at 325
Fahrenheit. Boned and unboned roasts (sixth to eighth ribs) were cooked by conventional and electronic methods. Only significant results are reported herein.
Objective tests using the Warner-Bratzler shear indicated roasts of Shorthorn animals to be the most tender of the four breeds.
Sensory analysis by an experienced panel of judges rated roasts of Hereford and Shorthorn to be most tender, juicy, and flavorful.
Conventional methods of cooking resulted in higher quality beef than did electronic cooking, Greater total losses, less juiciness, less flavor, and less tenderness were recorded for meat cooked by microwave activity. There was a high correlation between objective and sensory measure ments for tenderness and juiciness. Age of animal and shear values showed high correlation with the younger animals (11 months) in this study being less tender. Flavor was shown to be related to backfat thickness.
(113 pages) INTRODUCTION
Beef continues to be the most popular kind of meat on the
American table. The consumer wants leaner, more tender meat --m eat
that is juicy and has a pleasing flavor and aroma . Consumption of meat is high among settlers of new territory where meat is ordinarily
abundant, but usually decreases with density of population. Inhabi
tants of a region eat the food that is most abundant. European and
Asiatic peoples consume far less meat than peoples of the Americas.
The average American eats 95.7 pounds of beef annually (Ziegler, 1968).
This figure represents only beef consumed. Other meats and fish are also eaten, but in lesser amounts per capita.
Preparation and cooking of meat to make it acceptable for family consumption have been of concern to homemakers for many years . The relatively new method of cooking with microwave energy presents a new challenge to homemakers and researcher s to cook foods faster and at the same time to retain quality. Research has shown that method of cookery affects the tenderness of the beef.
Beef varies in texture and tenderness from muscle to muscle and from animal to animal. Muscles of greater use generally contain more connective tissue and are less tender than little used muscles. To prepare the less tender cuts of meat the homemaker has, in the past, been advised to use moist heat to soften the connective tissue.
Researchers have found that many such cuts can be satisfactorily oven roasted with dry heat at low temperatures for longer periods of time, 2 thus softening the connective tissue and yielding a tender, flavorful product.
Production of tender beef with a minimum amount of waste fat through a program of breeding Hereford, Shorthorn, Charolais, and Crosses of these animals has been under study by the Department of Animal Science at Utah State University for several years. In cooperation with the department, the Department of Food and Nutrition has conducted tests for tenderness, flavor, juiciness, and overall acceptability using standing rib roasts (ninth, tenth, eleventh, and twelfth ribs) of the experimental animals. This phase has been to study genetic effects upon mea t tenderness and other quality factors. An adjacent rib roast
(sixth, seventh, and eighth ribs) and two adjacent arm roasts were also made available from the left front quarter of each experimental animal for comparison of cooking methods.
This study was undertaken to compare and evaluate the qualities of tenderness, juiciness, flavor, and acceptability of less tender beef roasts cooked by conventional and electronic methods and to study the effect of breed, backfat thickness, and cooking method upon juiciness, tenderness, and flavor of tender cuts of beef. 3
REVIEWOF LITERATURE
Flavor components of meat
Meat flavor has been defined by Hornstein (1967) as an artifact
produced by heating a heterogeneous system containing nonodorous
precursors . Flavor-making ingredients are captured or encapsulated
with melting fat globules within the beef as it is being dry roasted
(Ziegler, 1968). The water soluble proteins which contribute greatly
to flavor and aroma are thus held within the beef,
It is agreed and substantiated (Hornstein and Crowe, 1960;
Hornstein, Crowe, and Sulzbacher, 1960; Batzer et al., 1960; Batzer,
Santoro, and Landmann, 1961; Cramer, 1963; Wasserman and Gray, 1965) that low molecular weight, water soluble materials are the flavor precursors in meat. Besides being water soluble, the flavor precur sors are cold water extractable. Earlier studies by Crocker (1948) had determined that meat flavors were in the juice of raw meat and that cooking developed the meaty flavor. It was thought that the precursors were probably a specific glycoprotein and inosinic acid. No single compound or class of compounds appeared to be responsible for the characteristic meat flavor during cooking. Batzer, Santoro, and
Landman (1961) suggested one or more carbonyl compounds were respon sible for chicken flavor in their research with poultry. The compounds may have been present originally as inosinic acid which was hydrolyzed.
Later studies indicated that various mixtures of glucose, inosinic acid, and a glycoprotein produced meaty flavors, but only certain amino acids in the glycoprotein were the necessary precursors (Batzer, Santoro, 4
and Landmann, 1962). Landmann and Batzer (1966) found inosinic acid
to be of major importance in combination with other compounds for fully
developed meat flavor. When these precursors were heated in fat, a
broiled steak odor was produced. A recent investigation by Zaika and
coworkers (1968) involved the separation of water-soluble compounds
respo nsib le for meat aroma and flavor. They concluded that amino acids
and sugars were present in all flavor-producing fractions and there was
no apparent requirement for specific components. These aroma producing
precursors are sti ll unidentified. Either free sugars or sugar phos
phates were involved in aroma development, but several amino acids
could be removed from the fraction without affecting the development of
aroma. The removal of tyrosine, phenylalanine, taurine, glutamic acid ,
creatine, creatinine, the purine derivatives inosi ne , inosinic acid,
and hypoxan hine did not affect aroma development.
Lean meat flavor has also been reported as being the result of the nonenzymati c browning reaction between carbo hydrates of low molecular weight and amino acids (Hornstein and Crowe, 1960; Batzer, Santoro, and
Landmann, 1962; Hornstein and Crowe, 1964) . Wood (1961) found from investigations using ox-mus cle extracts that color and flavor develop ment was the result of the Maillard rea ction.
Ziegler (1968) referred to the water-soluble proteins as the gravy making ingredients for they are rich in aroma and flavor. When cooking lean red meat from different animals , the meat aroma is basically similar since similar amino acids and carbohydrate compounds are found in lean pork, beef, and lamb. Variations in aroma are a result of differences in species, food, and environment of the animal (Crocker ,
1948). 5
Aroma is closely associated with flavor as part of the taste sen
sation (Levie, 1963). Blends of the primary tastes of sweet, sour,
bitter, and salty are responsible. But aroma accounts for the principal
flavor factors; and, according to Cramer (1963), three main classes of
compounds are the primary cause of aroma of meat. These three compounds
are carbonyls, nitrogen-containing materials, and sulphur compounds.
In their study of cooking beef in water and in fat, Sanderson,
Pearson, and Schweigert (1966) found that the difference in flavor and
aroma of beef roasted and boiled was due to the volatile carbonyl
compounds . A cooking apparatus which trapped the volatile components
was employed. The same number of aldehydes and ketones was identified
when beef was cooked in water as a slurry or cooked in fat simulating
a roasting method. The amount varied with the method of cooking and was greater for meat cooked in fat, but they added that some aldehydes
and ketones may result from the fat itself. They concluded that the
flavor differences may arise from the quantity and composition of alde
hydes and ketones that are released from meat by the heat of cooking in
fat or in water.
Fat also contributes to meat flavor because of flavor and aroma
components contained in the oils (Zeigler, 1968). The flavor is influ
enced by the oxidation of unsaturated fatty acids to form carbonyl compounds. Depending upon the concentration, the fatty acid oxidation may result in desirable or undesirable flavor . A second way lipids contribute to flavor is by being a storage area for fat-soluble compounds that affect the flavor when they are volatilized on heating (Hornstein and Crowe, 1960). 6
Wasserman and Gray (1965) studied the separated fractions from
fractionation of raw ground round of beef to learn more of its aroma
producing components. It was suspended in cold water , extracted,
filtered, and centrifuged to remove the fine particles. The subs t rate
was fractionated using paper chromatography to identify the vario us
fractions. After the water extraction, a grayish white fibrous resi
due remained which produced no browning or color change on cooking.
Neither did the residue possess any characteristic meaty aroma or
flavor . The hamburger was tough and tasteless. They found the aroma
producing components to be in the water extract which was serum-like
and blood-like. When the water extract was heated, the odors emitted were described as brothy, buttery, and oleaginous. Evaporation of the water resulted in pyrolysis and browning with resultant broiled steak
aroma. Pyrolysis accompanied evaporation of the water resulting in browning and a broiled steak aroma. These researchers concluded that water-soluble extracts of beef contain flavor precursors. These find ings are in agreement with Crocker (1948) who earlier found the flavor of raw meat to be mostly in the juice. Characteristic flavor was pco duced from cooking meat at a low temperature or in water which probably degraded the fibers to amino acids. He noted that cooked-beef flavor consists more of aroma than of taste.
Hood (1960) found roasts cooked by dry heat to be judged more flavorful than roasts cooked by moist heat. Neither Jenson (1966) nor
Stembridge (1968) determined any distinct flavor differences of beef roasts cooked by dry heat at different temperatures.
Tuma et al. (1963) studied the characteristics of the Longissimus dorsi from animals of differing age. They noted a slight advantage · of the older animals over the younger ones as regards flavor. Meats of younger animals have only slight odor, but as the animal matu re s, the odor, hence the flavor, becomes stronger (Levie, 1963).
Factors influencing juiciness of beef
Chara cteristic of meat judged highly palatable is a mois t, juicy s t eak or slice of r oast beef . Cooked meat juiciness may be separated i nt o two effects: first, an impression of wetness which is the sudden release of fluid when chewing meat, and second, a sustained juiciness resulting from slow release of serum as well as t o the salivary flo w stimulated by the effect of fat (Weir, 1960; Levie, 1963), Meyer
(1960) stated that the amount and quality of the juice when meat is chewed is an important factor in judgment of quality of the cooked meat.
Cooking procedure and the degree of doneness influence the juici ness of t he meat more than any other factors. Lowe (1955) reported t hat r oasts cooked rapidly are more juicy than those cooked slowly.
Time and oven temperature are also involved. Roasts cooked at the lower temperatures to well done are tender but dry. Jenson (1966) also found this to be true . Gaines, Perry, and Van Duyne (1966) reported from their study of cooking top round beef roasts that roasts seared and then cooked to an internal temperature of 140 Fin a 300 F oven had higher juice loss after slicing than seared meat held at 140 F and 158 F for 24 and 16 hours respectively, both of which showed greater evapora tive losses. However, surprising as it may seem, these authors found the 300 F roasted meat was more tender, significantly more palatable, and slightly less rare than the delayed service cooked roasts, Research on Choice grade top round roasts of beef to five different 8
internal temperatures by Marshall and co-workers (1959) indi cated that
as the degree of after the medium well done stage was rea che d, the rate of juice loss decreased. Weir (1960) advised that cooking losses and juiciness of meat are adversely affected by low cooking temperatures held for long periods of time. Veal roasted at 25 0 F and 315 F to the same degree of was more juicy and had lower cook ing lo sses at the higher temperature. Bramblett et al. (1959) cooked pairs of beef round roasts at 145 F for 30 ho urs and 155 F for 18 hours. This earlier study is in contra diction to th e above statements ; the y fo und the meat cooked at the lo wer temperature to co ntain more moisture. Taste panel scores for juiciness were consiste ntly greater for the beef cooked at 145 F. The ove n temperatures in the two st udies, however, are not comparable. It was found by Fielder, Moschette, and Mullins (1962) that when steaks from Semitendinosus and Longissimus doPsi muscles were cooked by dry heat , radiant heat, electronic oven, and deep fat cooke ry metho ds, juiciness was greatest in broiled steak, the dry heat method. Deep fat and electronic cookery resulted in the grea t est moisture losses, hence loss of juiciness. Methods which retain the fluid and fat during the cooki ng process result in juiciness in the cooked meat (Weir, 1960; Levie, 1963). Studies by J enson (1966) and Stembridge (1968) indicated rib roasts cooked at 325 F were more juicy than roasts cooked for a longer time at the lower temperatures of 225 and 250 F. The grade of the carcass also exerts an inf l uence on the j uiciness. Longissimus doPsi and Semitendinosus muscles from a USDA Prime carcass 9 were higher in fat content but lower in moisture content than other grades in the study by Fielder, Moschette, and Mullins (1962). Hood (1960) found no difference in juiciness in Good and Standard grade roasts. Many studies have shown close correlation between juiciness and fat content. Well marbled meat often is or seems more juicy than meat with less abundant marbling. Fat contained in the meat influences its apparent juiciness (Griswold, 1962). The fat melts upon heating and surrounds or penetrates the lean meat particularly where collagen hydrolysis has taken place (Wang, Rasch, and Bates, 1954). Roasts from yo ung animals, which characteristically have little marbling, often result in the cooked meat producing a watery effect on first chewing and later they are dry (Weir, 1960). Beef steaks of Longissimus dorsi from older animals which also had greater backfat thickness were more jui cy than s eaks from 6- and 18-month-old animals as reported by Tuma et al. (196 3) . Gaddis, Hankins, and Hiner (1950) found from their experiments with fluid removed from beef rib roast that any increase in percentage of fat resulted in higher panel scores for quantity and quality of the juice. They also suggested that fat stimulated the flow of saliva in the mouth and coated the mouth, thus prolonging the sensation of moist ness and richness during the chewing process with the resultant sensa tion of juiciness. Factors influencing tenderness of beef According o most research and consumer studies, tenderness ranks first among the palatability factors in the acceptance of beef (Weir, 10 1960; Rhodes et al., 1964). Numerous physical conditions and various handling prac tices have been found to influence tenderness. Stembridge (1968) found no significant differences for tenderness as measured by the Warner-Bratzler shear among several different breeds of beef in her studies with ri b and chuck roasts. There was a trend for roasts from Charolais animals to be more tender and juicy. Among the genet ic groups the means for tenderness, juiciness, and flavor as scored by the taste panel were significantly different. The Shorthorn breed scored lower for all quality factors. Jenson (1966) studied four genetic groups and found little difference in tenderness scores for rib roasts from Hereford and Hereford-Shorthorn Cross animals. Yao and Hiner (1953) reported similar findings. In a five-year study of tenderness among seven breeds of British, Zebu, and dairy type animals, Ramsey et al. (1963) found Jersey steers scored more tender than all others as rated by a six-'lllember panel, but the difference between Jersey and Hereford was not significant. Loins and round steak of Brahman steers were the least tender as determined by laboratory and family panels as well as by the objective shear-force method . Sharrah, Kunze, and Panborn (1965) evaluated rib and round roasts from Heref ord, Angus, Charolais , and crosses of these breeds. The straightbr~d Hereford scored highest in all quality factors for roasts from the round, but rib roasts of the Angus breed and its crosses were generally more tender, flavorful, and juicy than those from Hereford sire progeny . Tenderness is among the characteristics of beef that have been shown to have fairly high heritability (American Meat Institute 11 Foundation, 1960; Levie, 1963). Research by 11atthews and Bennett (1961) indicated that heredity is responsible for much of the variation in tenderness. Tenderness is involved with the growth of muscle cells, and they suggested that individual animal differences influenced tenderness to a greater extent than treatment methods. As the beef animal ages, physiological changes take place which render the meat less tender. The muscle fibers increase in size and the cell walls of co llagen surrounding them become thicker (Ziegler, 1968; Levie, 1963). As has been observed by Hiner and Hawkins (1951), beef tenderness decreases as animal age increases. Levie (1963) and Walter et al. (1965) are in agreement with this observation. Tuma et al. (1962) conducted research on the Longissimus dorsi and Semitendinosus muscles from beef animals 18, 42, and 90 months of age. The taste panel scored the older animals as less desirable and less tender. Kim, Ho, and Ritchey (1967) compared the tenderness and amount of co nnective tissue among three ages of beef animals: veal, baby beef, and mature animals. They reported no definite differences in panel scores for tenderness of Longissimus dorsi for the three age groups. Herring et al. (1967) confirmed that the content of collagen did not vary significantly with maturi ty but its solubility is significantly affected by maturity. The solubility of the collagen present in the meat influences the tenderness, and these researchers reported that panel scores for tenderness were higher where collagen was more soluble. Other researchers (Wilson et al., 1954; Goll et al., 1963) had found that total collagen content does not increase with animal age. Several workers have reported no significant relationship between meat tender ness and collagen c.ontent in meat animals (Husaini et al., 1950; Loyd 12 and Hiner, 1959; Adams et al., 1960; Parri sh et al., 1962). Muscles that have small amounts of co nnecti ve tissue are usually more tender than those with large amounts of connective tissue (Ramsbottom, Strandine, and Koonz, 1945; Ramsbottom and Strandine, 1948). Lorincz and Szeredy (1959) found that animals of low grade or those that are young or undernourished may have a large amount of con nective tissue. Generally the muscles of greater use contain more collagen and elastin (Hiner et al., 1955). Connective tissue and thickness of cell walls increase with age and exer cise; hence, tender ness decreases (Levie, 1963). This confirmed findings of earlier investigators that more connective tissue is found in t he less tender cuts of meat. There exists a wide variat ion of tenderness among muscles of any one animal. Even within a given muscle tenderness var i es. In the Longissirrus dorsi tenderness increases from center to both ends (Weir, 1960). Matthews and Bennett (1961) reported a decreased tenderness in the Longissimus dorsi farthest away from the bone. Muscle fiber size is an important factor in determining tenderness (Hiner et al., 1953). Meat with small fibers is more tender than meat with large fibers. Muscle fibers become larger as the animal grows i n size, weight and maturity. Tuma et al. (1962) studied the relationship of fiber diameter to tenderness in Longissimus dorsi and Serrritendinosus muscles. They noted a gradual increase in fiber diameter with increased animal age. Animals of 18 months and older had muscle fibers that were wavy, a condition indicative of age. After 24 months of age there was little change in fiber diameter . They concluded the fiber diameter was 13 a poor indicator of tenderness when effect of animal age was removed. The taste panel score for tenderness indicated lower and less desirable ratings as the size of muscle fiber increased. These researchers con cluded that "the effec.t fiber diameter may have on tenderness appears to be due to the animal-age-fiber-diameter relationship" (Tuma et al., 1962, p. 36). Matthews and Bennett (1962) conducted an investigation on beef animals to determine the effect of preslaughter weight gain on tender ness. Purebred Hereford and Shorthorn steers and heifers of 15 months average age and of similar genetic background were divided into two groups . The animals, randomly assigned to two feed treatments, were fed rations designed to produce rapid gains and slow gains. The treat ment was for 28 days prior to slaughter. The greater rates of gain produced animals of higher visual qualities in both live and carcass observations. But for these animals under 18 months of age, no dif ferences in tenderness were found. Wilson (1960) has stated that amounts of lean and fat in animal carcasses may be influenced by feed ing and rnanagemen t. Experiments involving the interaction of cations with muscle pro tein were conducted by Arnold, Wierbicki, and Deatherage (1956) and Huffman et al. (1969), The release of calcium by the muscle protein after slaughter reduced the amount of dehydration by calcium ion and affected the degree of tenderness positively. Huffman and co-workers fed sheep three calcium:phos phorus levels. Four of the seven groups received an antemortern injection of sodium phosphate which altered the pH of the meat. They concluded from their tests that no correla tion existed between tenderness and muscle pH. However, muscle and 14 blood calcium were inf luen ced by the differing calcium:phosphorus ratios . Warner -Brat zler shear determination showed lamb chops from the l ow ca lcium:phosphorus diet to be more tender than those of other calcium le vel s. Inje c tion of the sodium phosphate antemortem inc reased the tendernes s of the lamb chops . Swift and Berman (1959) and Berman 11961) have shown a relationship betwe en zinc content of muscle and tenderness. Significantly greater amoun s of iron were found in less tender muscles than in tender musc les by McClain and Mullins (1969b). S0ditm1, potassium, and calcium ions are involved with muscle pro rein and the water -h olding capacity of protein affecting tenderness of meat. Wietbicki, Kunkle , and Deatherage (1957) noted that certain reactions occ urring between 55 and 70 C promoted protein hydration. This reaction counteracted the effect of denaturation of protein, thereby preventing toughening. Webb et al. (1967) studied the rela ri0n of concen tration of various ions and tenderness. Low magnesium 1n particular seemed to be associa t ed with low tenderness scores. TPnderness was correlate d with the water -h old ing capaci ty. The work of McClain and Mullins (1969a) indicated that muscle pH affected the water-holding capacity. They found when the muscle pH was high, mo1s ure content was high also, which is in agreement with earlier resu lts reported by Walter et al. (1965). They further stated that meat hydration should increase with any rise in pH. Laakkonen (1969) has shown that better water-holding ca pa ci t y affects tenderness development. Tenderization has been ascr ibed · to the dissociation of ac to rnyosin and a shift or redistribution of ions during post -rigor storage 15 (Wierbicki, Kunkle, and Deatherage, 195 7). This activity within the muscles results in increased hydration and a tenderizing effect. Weidemann, Kaess, and Carruthers . (1967) in their research on pre and post-rigor muscle concluded that tenderness is produced by the d1srup ion of active filaments and by the breaking of the actin and myosin filament linkages. In a recent study by McClain and Mullins (1969b) large r amounts of actin were ext racted from tender muscle than from less ten de r muscle , substantiating the findings of earlier researchers that tenderness is related to the dissociation of the actomyos1n complex. A number of oth er factors influenced beef tenderness post-slaughter. Before the onset of rigor mortis, beef is tende r, and after rigor a gradual tenderization rakes pla ce (Wilson, 1960). During rigor mortis the ~us~le fibers shorten, causing a toughening. Paul and Bratzler (1955a) n~ted that any type of handling or cutti ng bef~re 3- 6 days of agi ng on the ca r cass reduced tenderness by interfering with the tenderizing pr oce ss. Method of handling the car cass greatly affects tenderness. Marsh and Leet (1966) stated that cha nges occ urring during immediate pos t-mortem and rigor mortis deter mine the structure of meat. These authors excised muscle from the carcass in a pre-rig or condition. From their study of the condition of the fibers as a result of cutting before rigor mortis set in, they suggested that the actin -myosin-contractile mechanism is involved in tougheni ng . The amount of s hortening that the muscle fibers underwent affected the tenderness of the meat. Excised pre-rigor muscle was free to contract . A 20 per cent decrease in length had no significant 16 effec . But 20 to 40 per cent shortening decreased meat tenderness. Previously Locker (1960) had suggested that toughening might be due o shortened muscle fibers during onset of rigor mortis. A shortened muscle 1s one which has contracted. He further suggested that chilling the whole carca ss without cutting into the meat in any way could restrict or prevent shortening in most muscles. He con cluded that relaxed muscles are more tender than partially contracted ones. The prac ice of hanging a carcass to cool and age imposes a strain on muscles and determines their final state. Marsh and Leet (1966) found shortening was minimal at 15-20 C, indicating an effect of tPmperature as well. From their studies of the influence of carcass position on tender ness, Herring, Cassens, and Briskey (1965) concluded that a shortened mus:le h3s increased fiber diameter and decreased sarcomere length which results tn a deciease in tenderness. Vertical and horizontal carcass positions were studied. The stretched connective tissue mak ing 1t thinner may be a factor in the increased tenderness of the muscles so stre ched by their positions during cooling and aging the carcass. Further study of stretched and contracted muscles by Herring, Cassens, anci Briskey (1967) has shown prevention of post-mortem shorten ing to be more important than maximum stretch in ultimate tenderness. After slaughter, beef is chilled for 24 hours during which time rigor mortis sets in. This is followed by a refrigerated aging period of up to four weeks. Proteolytic enzymes, particularly cathepsin, act upon the connective tissue to render the meat more tender (Ziegler, 1968). Maximum tenderness for beef is usually attained in two weeks 17 of aging. The agi ng proc ess may co nt i nue slowl y during storage by te 0 zJng LongPt s tora g e res ult ed in more tender s teak acco rding to Paul and BYatzler (1955a ), Tuma et al. ( 1962 ) r eported that t he ~fr?'t ~f ?g1n g ~n end er ne s s varied with animal age. There was l itr l " d ifferen,:e among an imals 18 months old, but meat was more rende• from 42- and 90-month - old an .ima l s a fte r ag i ng 14 days . A study by Davey and G1lber (1 969 ) sho wed t ha t te nderness of beef r esults tram he scr,;r ura l ch,mges of l oss of linkage between myof i brils and the woa~ening of Z line s by disr up tio n or dissolution during aging. Marbling , f le eks or a webbing :,f fat deposited throughout the lean m~scl~ has been rated as a mos t import ant beef qual i ty f acto r (Goll , Kline , and Mis kus , 1965 ; Zi egl er , 1968) . Goll and co-workers conduc to d rest3 on t he ri b cu t of 72 carc asses from an i mals of 15-18 months , 20- 14 months , and 8- 10 years, Shear f or ce determinat i ons and ras'e panel e 1,:alua t ions we,e conducted . Their results showed little ·elarionsh1p cf marblin g to ende rness , ju ic iness, or flavor . Age was the more import ant fac t or i n th is st udy. Tuma et al . (1962) Yep~rred gzeat er associ a t i on betwee n marbl i ng and tenderness as ani- mal ag 0 i ncreased. Data ana l yses from a s t udy of beef muscle character- 1a11 - s by Walter er al. ( 196 5) d emons trat ed that marbling had no effect on tenderness, bu t advan cin g car cass age or maturity r esulted in decreased renderness. Marbling i s of mi nor importance in tenderness ~f ovine muscle (Carpe n t er and Ki ng, 1965). Ramsey et al . (1963) con c luded rh at fac ors oth er t han ma r blin g pla yed impor tant roles in be 0 tender ne ss . Suc h f a cto r s included b r eed and age of animal in part 1 - 0,la r , but muscle co nnecti ve i ssue and method of co oking also gre atly affect enderne ss. 18 Ziegler (1968) explained that marbling is valuable in steak. As rhe at particles melt, they encapsulate the cells and hold in the w~ter-soluble proteins which contain the flavor and aroma constituents. The amount of marbling noted in the rib eye between the twelfth and thirteenth rib largely determines the official USDA grade of beef. Weir (1960) has noted two general changes which occur when meat ts ·ooked: (1) muscle fibers toughen; (2) connective tissues soften ~, be come more tende r. She stated that a long heating period and a moist 3tmosphe re are important for softening connective tissue whereas meat cuts with small amounts of connective tissue may be co oked for a shorter time in dry heat to minimize the toughening effect on the meat fibers The impression of tenderness is dependent upon the ease with which reet-h sink i nto the meat and break the meat into fragments as well as upon the amount of fiber and co nnective tissue which remains after chewing. Change in tenderness of meat is due to several factors as outlined by Me yer (1960). The pr oteins are denatured and collagen is hydrolyzed to g~latin 9s the internal temperature increases; globins are denatured pr1du c 1ng color change ; moisture losses occur through evaporation and dr1p formation ; and fat cel ls rupture and disperse through the meat along che paths of th e degraded col lagen. Cover (1941) stated that hyd,olys1s of co llagen takes place after an internal temperature of between 57 C and 65 C is attained. In a later investigation (Cover, 1943), she observe d that slow heat penetration of 30 hours or more resulted in ender meat. Bottom round roasts cooked to well done at 176 F were moist , very tender, and mealy. Bramblett et al. (1959) 19 studied mois t heat cooking of less tender round roasts. Panel evalua tion and Warner-Bratzler shear results indicated that the meat roasted at 63 C for 30 hour s was more tender than that roasted at 68 C for 18 hours . At the lower temperature cooking losses were also less. Contrary to these earlier investigations, Gaines, Perry, and Van Duyne (1966) reported top round roast s cooked at 300 F to 140 F internal tempetature were more tender than paire d roasts held for long periods at lower temperatures. Their cooking procedure included initial sear ing of In their investigation of cooking time and temperature effects on beef co oked in tubes, Draudt, Machlik, and Rimstidt (1964) reported three heat-produced changes taking place: (1) collagen shrinks increas ing tende rn ess ; (2) muscle fiber proteins harden decreasing tenderness; and (3) collagen softens increasing tenderness. They found collagen shrinkage in the Longissimus dorsi between 56 and 58 C and evidence of the fiber hardening reaction above 60 C. Delayed servi ce cookery of institutional-sized roasts was conducted by Funk, Aldrich , and Irmiter (1966). Paired short loins were halved and cooked by two delayed service methods at 204 C and 149 C and by the conventiona l method at 149 C to rare, an internal temperature of 52 C. The two holding periods for the delayed service roasts were 6 and 18 hours at 60 C. Roasts cooked by the conventional method were deter mined ro have higher palatability scores except for aroma and lower total cooking losses. They recommended convent ional roasting to be the most desirable method on the basis of their findings. Cover, Hostetler, and Ritchey (1962) found shear force values to be significantly higher 20 i n well done Longi ss imus dor si steaks t ha n i n r are ones . The panel scored s uc h meat as tough . The effect of cooki ng upon meat depends to a large extent upon whic h rea c tion predominates , hydrolysis of col l ag en or coagulation of prot ein. The time fac t or i s more impor t a nt in s of t ening collagen and t he t emperature factor is more important in to ughening fiber (Weir, 1960) , These facts are in agreement with Lowe (1955 , p . 228) who stated , "The effect of cooking on tenderiz i ng the meat depends upon the ba l anc e between the exten t of softening t he co ll agen and hardening the musc le fibers. " Effects of cooking method Tr a ditionally moist cooking methods have bee n recommended or found suitab l e for the less tender cuts of meat and dr y cooking methods , for the t ende r cuts. In re cent ye a rs the use of the electronic oven for cooking by mi c rowaves has been introdu c ed . Dry hea t i mplies roastin g uncov e red in an oven, broi l in g , deep fat frying , or pa n- fry ing wit hout added moisture. When meat i s r oa sted in an uncovered pan, the length of coo kin g ti me is longer , but cookin g losses are less, nutritive losses are less , and the meat is more pal a t able (Lowe, 1955). From more recent studies evidence indicates that dcy h ea t methods are often suit a ble for both t ender and less tender cuts (Gr iswnl Stembridg e, 1968). Moi se heat cookery implies the addition of moisture , or tightly cover i ng the cooki ng co ntain e r wi t h a l id , or enve l o ping t he meat with an alu minu m foil wrap so that mois t ure and steam are held in during 21 the entire cooki ng period of at or near boiling temperature. Braising, b:>i. J 1 ng, s ewing , and pot roasting are examples of cooking with moist hP3.t"' Hood (1960) carried ou t an experiment on beef shoulder roasts coo ked roan internal temperature of 170 F. One roast of a pair was ·0oked at 300 Fin dry heat of a gas oven , and the other roast was wrap ped c l0sely 1n aluminum foil to cook in its own moisture in a 300 F gas 0ven. She co ncluded that , for these Good and Standard grade roasts, tho ~-y heat method resulted in a more juicy, tender, and flavorful roasr with less weight loss even though it required the longer cooking t •me. lles•1lts of studies reported by Lowe (1955) were in agreement with these conc lusions. C":'ok1ng with mi c rowaves in an electron ic oven is an entirely dif fQr~u~ principle than cooking with dry or moist heat. Conventional ~~k~ry r~ nsists of convection c urrents from the high t~nperature of rhe 'Jvcn ~nvironme nt conducting heat into the food. The food itself b~-0mes warm and cooks in electronic cookery, leaving the utensil, oven air , and ~ven walls coo l. Since here is no increase of ambient temper .ature, the coo l cooking conditions and speed of preparation are advant ages irod by Van Zante (1968). During World War II radar was developed and used extensively. When 1t w~s d1srovered that some materials became hot when exposed to the rn1crowa 1re sig nals, scientists developed their use for cooking purposes. Material t0 be co oked is ex posed to a rapidly al ter nating field and 1otPr-molecular fric tion is prod uced. This is an absorption process !Allaire , 1966). G0ldblith (1966) stated that in foods only heat is 22 produ :e d as a result of the microwaves, and the microwave frequency and characteris ti c s of the food determine the amount of heat, Cooking 1s accompl ished by the entry i nto the food of the high frequency radio waves , mi.cro waves (Schneider , 1968). A magne t ron oscillator, which is a vacuum t ube , changes electricity into mi r rowaves. The microwaves are beamed into the cooking chamber. Rotari.og metal blades break up the stream of waves to distribute them rhrough~ut the oven. The metal walls also serve to direct the waves 1nto he food by reflection (Blatz, 1969). Microwaves have an affinity for water with its polar characteristics and enter the food setting the molecules in motion,thereby producing fr i n i on and heat which cooks the food (Fox and Dungan, 1968; Fenton, 195 7). The surface of the food becomes hot and heat is conducted inward. The micto w~ves are capable of penetrating toward the center for two or rhree inches (Fenton, 1957; Schneider, 1968), so if the mass is large, ro~k1ng to the interior is accomplished only by the conventional method .,f heat co nduction, Van Zante and Bishop (1967) have conducted exten sive resea rch on size and type of load and their effect upon cooking t irne in the electr onic range. Evidence indicated that cooking time needs robe increased as weight or size increases to attain the neces sary internal temperature rise. They also noted that the more surface area expo~ed to the waves, the greater was the evaporation. These facts are 1n agreement with Fenton (1957). Two freque ncies for cooking in electronic ovens have been assigned by rhe FCC: 915 and 2450 MHz, MHz is mega mil l ion Hertz cycles per sec~ nd . The number of cycles per second determines the wave length; the 23 f~we~ c ycles iss ue longe r waves (Schneider, 1968). The shorter wave \e rygrh (higher frequency) is capable of supplying more energy to the f 0 od, bu' if rhe mass is very thick, this frequency is too high for pr:1pe .. p'?'netration. Electronic ovens have a high and low speed which ,J otr. ~ ls rbe speed of bombardme n t of electrons of the wave length dPSlg~ed fo r that ove n. Cooking time for foodstuffs is greatly shortened in the electronic ~ven ; ~nly Joe-half to one - tenth the time required by co nvent io nal ovens 13 ryeedPd IPe nton, 1957). Apgar et al. (1959) found conventional cook ing 0f the~~ pound pork roasts required five times as long as roasting ~hew 1~ the e l ec tronic range. 'Ian Zan•e (1968) pointed out that to reposition food during the oJ ki ng proces s aids in attaining more even cooking. She has also ~r,3t--ed rhat the short - time heating and cooking of food elec tronically pfodure13 more uneven internal heating than does the co nventional eJ.ec- t r 1" ra nge which requires a much longec period of time (Van Zante, 1959). In rheir study of the destruction of bacterial content of food, DQssPl , Bawersox , and Jeter (1960) found a slight superiority of ele c r--:'Jn1c over co nvent ional cookery. Bacterial destruction was as effec t11,e 1n 4-5 minut es in th e electronic range as 30 - 40 minutes of co nuent 10 0;,l baking of custard, eggs, and ground beef. The instantaneous gene~a~i'Jn of heat may have been the importan t factor. Co~king utensils for use in the electronic oven must, of necessity, be of non - metal. Metal re.fleets the waves and prevents penetration of 'he mi c·o wave e nergy (Schneider, 1968). Cassero l es and baking dishes of glass, eart henware, or pyrex are suitable (Van Zante , 1961). She 24 f.ound al so that contents in round pans heat more evenly than in square pans, and contents heat more quickly in ovenproof glass than in earthen ware ut ens ils. Nwner ous studies have been conducted in recent years on the methods of coo ki ng beef using the three heat medit.nns of moist, dry, or microwave pene trat i on. One o f the earliest investigations concerned the feasibility of a pp ly i ng e l ec tronic cookery in large-scale feeding operations. Bollman et al . ( 1948) concluded that weight losses and time to cook large cuts o f mea t made cooking by microwaves uneconomical even though an accept ab l e pr ~duct was prepared. Stevens and Fenton (1951) noted that even s li ght unde r cooking or overcooking by microwaves made a difference in palat abilit y . Apgar et al. (1959) cooked pork roasts in conventional electric and e l ec tr oni c ovens. The electronic cooking resulted in decreased juici ness and te nde rn e ss s cores and the moisture content was less, but there was no sig nif ic ant difference in any of the palatability factors. Large cut s of lamb, boned and rolled, were cooked unco vered elec tron ic al l y and conventionally by Headley and Jacobson (1960). Electroni- 0ally - ooke d lamb was more well done and showed greater shrinkage and e vapo rati ve loss , Conventionally cooked meat was more juicy and had be t t e r l amb f lavor. In a similar experim ent, but using top round of beef , Mar shall (1960) noted higher cooking losses and lower ratings for appe a ranc e, tenderness, juiciness, and flavor in the electronically coo ked bee f. These findings agree essentially with those of Kylen et al. ( 1964). In addition these researchers reported the chief disadvantages 25 of microwave cooking to be the adverse effects on color , texture, and flavor. Oven-broiled and deep-fat f r ied lamb chops were significantly more tender and showed less cooking loss than chops that were cooked in the electronic oven (Carpenter and Ki ng, 1965) . These fi ndings were in agreement with those of Headley and Jacobson (1960), Fielder, Moschette, and Mullins (1962), Apgar et al. (1959), and Braniff et al. (1961), but were in disagreement with the results in experimen t s with poultry meat by Monk, Mountney and Prudent ( 1964) . Carpenter, Abraham, and King (1968) compared the tenderness and cooking losses of beef rib steaks cooked by the three dry heat methods of oven broiling, deep-fat frying, and microwave cooking. Steaks judged least tender had been cooked electronically and those most tender were cooked in deep fat. Steaks were more tender when cooked electronically if more marbling were present. Fenton (1957) reported more cooking drip resulted from electronic cooking of meat than from other cooking methods. Advantages of microwave heating include a cooler working .environ ment, a penetrating quality, selective absorption of radiation by liquid water, a controlled rate of heating, and speed of preparation (Allaire, 1966; Van Zante, 1968 ; Huxsoll and Morgan , 1968). Fenton (1957) has stated that the moisture content of cooked foods may be as high in one method as in another if no overcooking occurs. 26 METHODOF PROCEDURE History of meat Beef used in this study was obtained from the Department of Animal Sc ience at Utah State University from among heifers, steers, and young bulls of a breeding experiment being conducted by the department for mor e t ender meat with less fat. Hereford, Shorthorn, Charolais, and Shorthorn-Charolais cross animals were represented. The feeding program for the experimental animals included being on pasture with their mothers until weaning following which grain and hay were offered during a three-week adjustment period. After the adjustment period and for approximately 140 days before slaughter, the feed-lot ration consisted of three pounds of corn silage in the morning and one pound of dry hay in the evening in addition to feed pellets ad l1b i tum (Table 1). The animals were slaughtered between November 1968 and June 1969 at a local meat packing plant where the meat was also inspe cte d and gr aded. At the time of slaughter the age range of all animals was f r om 11 to 34 months. The majority of animals were graded USDA Choice, but four grades (Prime, Choice, Good, and Standard) were represented (Tabl e 18) . Backfat thickness was measured at three locations on the twelfth rib c ut, and the average of these three, stated in inches, was recorded as backfat thickness of the animal. 27 Table 1. Composition of feed pellets Constituents Per cent Alfalfa 25 Straw 10 Oats 14 Barley 20 Corn 10 Cottonseed Meal 5 Iodized salt 1 Dried molasses beet pulp 14 Bentonite approximately 1 Total 100 Each carcass was aged for seven days at 34 F before being cut, coded with an identifying number, and wrapped in heavy polyethylene bags for quick-freezing and storage. Roasts for use in this study were cut from rib and arm areas of the left fore quarter of each animal (Figure 1). The rib roasts were as follows: number 1 roast included the ninth, tenth, eleventh, and twe l f th ribs; number 2 roast, the sixth, seventh, and eighth ribs. The amt roasts from the chuck area (Figure 1) were numbered 3 and 4 for the lower and upper roasts respectively. Weight of the roasts varied from animal to animal. The mean weights are presented in Table 2. Table 2 . Mean weights of rib and arm roasts Unboned Boned Roast gm lb gm lb Rib, number 1 4055.5 8. 94 Rib, number 2 3995.0 8 . 81 3393 . 1 7.48 Arnt, number 3 3867 . 5 8.53 Arm, number 4 4434 .4 9. 78 28 4 3 Arm roasts Figure 1. Diagram of carcass showing location of rib and arm roasts. 29 Design of study Rib roasts 1 and 2 and the two arm roasts (3 and 4) from the chuck area were considered separately, permitting a threefold study of the quality factors of beef roasted by several methods . Each roast was assigned a three digit code number at random as reference for evalua- tion by the taste panel. Arm roasts. The first experiment consisted of arm roasts from ~·,.. thirty animals. Two roasts from each of two animals were matched as closely as possible for age, breed, and sire. The statistical design was one of partial confounding with a 2 x 2 factorial plan relating I effe c t of kind of oven or surface unit, type of heat (dry or moist), and interaction between the two disregarding effect of breed and sex of animal (Table' 3). Five replications of each of the treatments were 10 made. ~~ ~our roasts were cooked each day and were assigned to four methods of cooking in a random fashion. Treatment 1 involved the application of the dry heat of an elec- 1 tric oven. Meat was roasted at the oven temperature of 250 F to an internal temperature of 160 F. Jenson (1966) used dry heat for arm roasts of approximately the same size. The most desirable flavor for arm roasts was py dry heat at a lower temperature for a longer period of time. She recommended that the oven temperature be no lower than 250 to 275 F to prevent dryness in 7 to 9 lb roasts. Treatment 2 consisted of dry -r oasting in an electronic oven,2 set on low speed. Roasts wer e removed at an internal temperature of 1 General Electric institutional-sized oven. 2Tappan electronic range (2450 MHz). J O Table 3. Experimental design for cooking adjacent arm roasts Roast No. Roast No. Treatment Animal Animal Conv. Conv. Elect. Elect. Dry Pot Dry Pot Oven or surface JE 3 4 5E 3 4 unit 180 4 3 14C 3 4 1360 3 4 1610 4 3 151E 4 3 157E 4 3 lF 4 3 13F 4 3 Conv. Elect. Conv. Elect. Dry Dry Pot Pot Type 59E 3 4 63E 4 3 155E 4 3 161E 4 3 lOE 3 4 12E 3 4 6E 4 3 16E 4 3 112E 3 4 122E 4 3 Conv. Elect. Elect. Conv. Dry Pot Dry Pot Oven x type 57E 4 3 1570 4 3 Chill 4 3 Ch/12 4 3 1550 4 3 119E 4 3 123E 3 4 llOE 3 4 143E 3 4 124E 3 4 31 150 F. Power input of the electronic range was checked each cooking day by the method described in the manufacturer 's specifications. Tr eatment 3 was the conve ntion al method of top-of-stove pot roasting on the surface units of a regular household type range. 1 The meat was cooked to an internal temperatu re of 160 Fin a covered roast ing pan to which 105 ml (one-half cup) water had been added . Treatment 4 consisted of moist-heat cooking of the roast in the electronic oven. A cellophane covering completely enveloped the glass pan to which had been added the meat and 105 ml (one-half cup) water. Cooking continued on low speed to an internal temperature of 150 F. Rib roasts. All roasts in the second experiment were of the ninth, tenth, eleventh , and twelfth rib cut. Roasting was done at 325 F to an internal temperature of 155 Fin an automatic electric oven 2 designed for meat research. Roasts were chosen at random and cooked two or four at a time depending on their size. The third experiment used a random block design (Table 4). The sixth, seventh , and eighth rib cut of prime rib from each of 40 animals ,r was cooked to study the relationship of electric oven dry heat to electronic oven cooking by microwave activity and to compare qualities of boned and unboned rib cut roasted conventionally and electronically. Four rib roasts, one from each of four animals, were grouped as homogeneously as possible as to age, breed, sire, size of roast, grad~, and any other similarities deemed advantageous. Roasts were randomly assigned to four cooking methods. Method 1 consisted of roasting the 1westinghouse. 2nespatch Oven Compan y , Minnea pol is, Minnesota. 32 Table 4. Experimental design for cooking number 2 rib roasts Animal Boned- Method Block Number Unboned 1 3E Boned and tied Conventional SE Unboned Conventional 6E Unboned Electronic lOE Boned and tied Electronic 57E Unboned Conventional 59E Boned and tied Conventional 63E Boned and tied Electronic 151E Unboned Electronic 3 18D Boned and tied Conventional 14C Unboned Electronic CHiil Unboned Convent ion al CH/12 Boned and tied Electronic 4 136D Unboned Electronic 157D Boned and tied Electronic 161D Boned and tied Conventional llOE Unboned Conventional 155D Boned and tied Electronic 155E Boned and tied Convent iona 1 12E Unboned Conventional 16E Unboned Electronic 6 123E Unboned Conventional 143E Boned and tied Electronic 124E Unboned Electronic 157E Boned and tied Conventional 161E Unboned Electronic ll2E Boned and tied Conventional 122E Boned and tied Electronic ll9E Unboned Conventional 8 71F Boned and tied Conventional 67F Unboned Conventional 13F Boned and tied Electronic lF Unboned Electronic 9 5F Unboned Conventional 30F Unboned Electronic 26F Boned and tied Conventional llF Boned and tied Electronic 10 17F Bon ed and tied Electronic 21F Unboned Conventional 23F Boned and tied Conventional 69F Unboned Electronic 33 unboned meat to an internal temperature of 155F in an open pan in the ~espatch oven set at 325 F, with upper and lower heating unit control switches set at medium. In Method 2 the unboned roast was cooked by microwave activity to an internal temperature of 140 F. The lower internal temperature for rib roasts cooked electronically was necessary due to increased rise of internal temperature after removal from the oven. A preliminary study on 8 to 9 lb roasts indicated that the internal temperature tended to rise 20 to 30 F after removal from the oven. The meat keeps cooking; therefore, in order to have meat cooked to a final degree of medium doneness, it was necessary to stop the cooking process at the lower internal temperature. For each of methods 3 and 4 the roast was boned, rolled, and tied with string before being roasted conventionally on a wire rack for method 3 and electronically for method 4 as described above. Sample preparation Roasts were thawed in their polyethylene bags at room temperature for the first six hours and in a refrigerator for 18 to 24 hou rs. The internal temperature of the roasts ready for cooking averaged 4.2 C for arm roasts, -0.5 C for number 1 roasts, and 2.4 C for number 2 roasts. The two experiments involving electronic cooking required a higher internal temperature to begin roasting since cooking by microwaves depends upon moisture or liquid water for absorption of the radiation (Huxsoll and Morgan, 1968). Previous studies have shown that there should be no ice crystals in the center . The thawed meat was unwrapped, dried, and weighed on a Toledo gram scale. Measurements of depth of number 3 and number 4 roasts 34 and backfat thickness at the eighth rib on number 2 roasts were made. Arm and boned rib roasts to be cooked in electric ovens or on the surface unit were placed on racks in preweighed aluminum foil-lined metal pans. The number 2, 3, and 4 roasts to be cooked electronically were placed in pyrex roasting pans on flat glass lids used as trivets to keep the meat off the bottom of the pan and out of the drippings. Suggestions were given by the manufacturer for roasting meat in the electronic oven. For more even cooking, the roast should be turned once. Therefore, approximately half-way through the cooking period, arm roasts were turned over and the cooking resumed. From observa- tions on preliminary rib roasts cooked electronically, the front and rear sides of these large roasts did not cook evenly. Rib roasts were therefore turned three times. Cooking was begun with fat side down for about one-half the cooking time. Then the meat was cooked approximately one-eighth the time on each cut side and cooking com pleted to the desired degree of doneness with bone or boned side down. The number 1 and 2 rib roasts to be cooked by conventional oven heat were placed bone down with rib ends and chine bone in contact with the aluminum foil-lined metal pan. Aluminum foil lining was used for ease in getting cooked weights and cleaning of pans. Internal temperatures of the roasting meat were recorded. In the 1 electronic oven a special thermometer was inserted in the center of the largest muscle. A right-angle Centigrade thermometer was used to determine 1Taylor Instrument Co., Rochester, New York. 35 Internal roasting temperature of rib roasts in the Despatch oven were 1 recorded with a potentiometer from a probe placed in the center of the Longissimus dorsi to halfway the length of the roast. A single probe was used following the pattern of Stembridge (1968) who used only the temperature reading of a centrally located probe in her statistical analysis so that final internal temperature s taken with thermometers and probes at similar locations would be comparable . All meat was roasted without salt or seasoning of any kind. When the desired internal temperature was reached according to the experimental design for each of the experiments, the meat was removed from the oven and allowed to stand at room temperature. The maximum internal temperature reached during the standing period was recorded. Each roast was allowed to cool to an internal temperature of 140 F. The cooked meat was boned and the outside browned slice of meat removed before samples were taken for objective and sensory testing. Objective methods of evaluation Meat and pan with drippings were weighed together and separately . Drip, evaporative, and total losses were ca l culated from the weights recorded before and after cooking. To determine the effect that bone may have upon the degree of Brachiaiis muscle adjacent to the round arm bone and from the Longi ss imus costarwn beneath the rib bone of the cooked meat. Samples, trimmed of 1spee donax G, Model S. , Leeds and Northrup Company. 36 any fat and one-fourth inch of browned surface, were wrapped in alumi num foil and frozen. Samples were chopped finely while still frozen on a chilled cutting board with a sharp knife to retain moisture and prevent drip loss. Approximately 10 gm of the cut meat was weighed on a Mettler balance into tared, oven-dried sample cans and dried in a vacuum oven until a constant weight of dry solids was reached. The difference between moist and dry sample weight was considered the moisture lost. Tenderness of cooked meat was determined with the Warner-Bratzler shear apparatus which measures the number of pounds pressure required to shear a one-inch core of meat against a dull-edged blade. Three cores, one from each of the Biceps brachii, the Tri ceps br ach ii , long head, and the Triceps braehii, lateral head, muscles of the arm roasts, taken parallel to the fibers of the meat, were used for testing tender ness. The average of the three measurements was used in the statisti cal analysis. Lateral, medial, and dorsal cores were taken from the Longi ssimus dorsi of the rib roasts, and the average of these three determinations was recorded as the amount of shear for ce ex erted. Juiciness was measured by the amount of juice pressed from a 75 gm sample of cooked lean meat taken from the cores and areas inunedia t e l y adjacent to them. The meat was cut finely, placed in the cup of the hydraulic press apparatus (Succulometer), and gradual pressure was exerted to 2000 pounds per square inch and held for five minutes. Figure 2 shows the succulometer used for juiciness determinations . The fluid was collected in a graduate cylinder, and the amount was re corded to the nearest 0.1 ml. The color of the extracted fluid was also noted. Press lJ Meat core LJ D chamber Hydra ul ic cylinder Frame Pressure Pump handle ,1 '1 -·9J~e ~ I I ] I~ n:b rrtu __,w Figure 2. Diagram of succulometer used for press fluid determinations (from Stembrid ge, 1968, p. 29). 38 Sensory method of evaluation A panel of eleven experienced judges evaluated the cooked meat for flavor, juiciness, and tenderness. Three men from the Department of Animal Science and one man and seven women from the Department of Food and Nutrition judged samples of lean, unbrowned meat at room tempera ture. Samples for each judge were taken from an assigned position or muscle and each panel member received meat from that respe c tive area for each roast. Samples for the judges were cut adjacent to or from a slice of meat immediately below the core areas for relating to obje c tive evaluations. Two adjacent samples approximately one-half in ch square were wrapped in aluminum foil for each judge. The panel of judges scored samples from each roast according to a hedonic scale of weighted adjectives (Appendix B). A score of nine indicated extremely full flavor, extremely juicy, or extremely tender in each indicated category; a score of one represented lacking in flavor, extremely dry, or extremely tough. Statistical methods An analysis of variance was made for all variables in each experi ment. The data of each experiment were subjected to an analysis of variance to determine differences as a result of cooking method, breed, and backfat thickness. The statistical evaluation was made for sensory and objective data. Judges' scores were combined and averaged. Correlation coefficients were determined among variables including appropriate combina tions of sensory evaluations and objective measure ments. 39 RESULTSAND DISCUSSION Arm roasts Objective measurements. Tenderness values as measured by the Warner-Bratzler shear device were similar for all arm roasts. The interaction of oven and type of cooking (moist or dry) indicated a tend ency toward influencing the tenderness of the cooked meat (Tables 5 and 19). Roasts cooked electronically tended to test slightly less tender, possibly because cooking took place much faster with little time for a tenderizing effect on the collagen. However, there was no significant difference among variables due to oven, type of heat, and interaction of the oven and type of heat. Jenson (1966) found less tender cuts dry roasted at 225 F were significantly more tender than at a higher oven heat. A recent investigation by Bayne, Meyer, and Cole (1969) resulted in more tenderness in beef rounds when cooked at low temperature for a long period of time. Headley and Jacobson (1960) concluded that the method of cooking lamb roasts in ele ctro ni c and con ventional electric ovens showed no relation to the shear values obtained. However, Carpenter, Abraham, and King (1968) found microwave cooking of beef rib steaks to be least desirable and produced less te~der meat than did other dry heat methods . Work done on cooking pork · cuts by Apgar et al . (1959) had also indicated that electronic cooking decreases t enderness. Figure 3 i ll ustra tes t he variation in tenderness as affected by cooking method . Gr eate r strength was required to shear cores from 40 Table 5. Mean scores and standard errors of objective measurements for arm roasts Source of Shear Press variation forcea fluid*b lb ml Oven Conventional 20.0 ± 0 . 85 3.0 0.59 Electronic 20.1 ± 0 . 85 3 . 7 ~ 0.59 Type of heat Dry 19 .7 ± 0.89 2.3 0 . 52 Moist 19.6 ± 0 . 89 4 .0 ± 0.52 Oven x type Conventional dry 17.1 ± 0.28 1.3 ± 0 . 07 Electronic dry 19 . 0 ± 0 .28 2.0 ± 0.07 Top-of-stove-moist 21.3 ± 0.28 3.9 o. 07 Elect ronic-moist 21.1 ± 0.28 4.0 ± 0.07 *Significant (P < .05) aLower value indicates more tenderness bHigher value indicates more jui ciness 41 32 --Mean 28 24 .0 20 rl - - 9.5 ..· 17 .1 <1) 16 ~"~'" .c"' ~ en 12 8 4 I II III IV Method Method I. Conventional oven, dry heat Method II. Electronic oven, dr y heat Method III. Top-of-stove cooking, moist heat Method IV. Electronic oven, moist heat Figure 3. Range of Warner-Bratzler shear values for tenderness as a result of methods of cooking arm roasts (lower valu e indi cates more tenderness). 42 electronically cooked meat than from that conventionally cooked (dry type in oven and moist type on top of stove). A higher reading indi cated less tenderness of the core being sheared. Inasmuch as tender ness varies even within muscles, the average shearing value of three cores was used in the determination, Other workers have also used this method (Paul and Bratzler, 1955b; Stembridge, 1968). No value was lower (indicating more tenderness) than that determined fo r the conven tional dry heat method of cooking. There was a significant difference in the amount of press fluid by type of heat (P < . 05) indicating meat covered during roasting retained more moisture (Table 5). The mean score for volume of fluid extracted from meat of dry heat methods was 2,34 ml as·compared to 3.96 ml for moist heat cookery. Jenson (1966) also found arm roasts cooked by con ven tional dry heat at a low temperature of 225 F to be less juicy but also more tender than similar roasts cooked at 325 F. Contrariwise, Hood (1960) fo und dry heat cooking of beef .roasts (Triaeps braahaii) to produce a more juicy product than moist heat cooking. In this investi gation the effect of oven on press fluid was greater than the effect of interaction of oven and type of heat (Figure 4). Meat cooked electroni cally tended to be much less juicy. Past investigations are in agree ment with this observation. Pork chops, patties, and roa sts were less juicy when cooked electronically than when cooked conventionally (Apgar et al., 1959). Mar shall (1960) and Fielder, Moschette, and Mullins (1962) reported electronic cooking of beef resulted in a lower vo lume of press fluid than conventional cooking. 43 1 --Mean ..... 8 s ....."d 6 ::, ...... 4 3,9 - 4.0 I II III IV Method Method I. Conventional oven, dry heat Method II. Electronic oven, dry heat Method III. Top-of-stove cooking, moist heat Method IV. Electronic oven, moist heat Figure 4. Range of press fluid values as a result of methods of cooking arm roasts. 44 Sanderson and Vail (1963) found the amount of press fluid decreased as the internal temperature of the roast increased. The inte~nal temper atures of the arm roasts in the present study varied. Roasts cooked conventional ly were removed from the oven and the top-of-stove heat when an internal temperature of 160 F was reached. Only a slight addi tional rise of temperature upon removal was noted, and all such rises were not measured . The internal temperature of arm roasts cooked elec tronically rose from 8 to 17 degrees after being removed from the oven and allowed to stand at room temperature. The temperature rise and amount of press fluid measured were not consistent from roast to roast. Cooking losses. Total losses were more influenced by oven than by type (dry or moist heat) or interaction of the two (Table 6). In all replications arm roasts cooked electr onical ly exhibited greater total losses. Earlier investigators also found electronic cookery to result in high cooking losses (Bollman et al., 1948; Kylen et al., 1964). Drip losses were greater in moist heat cooking and were significant at the 5 per cent level. Evaporation losses were greater in cooking with dry heat. Moisture loss by evaporation was very small from roasts contained in tightly covered cooking utensils. Present results agree with those of Apgar et al. (1959) who deter mined that electronic cooking did decrease moisture content of po rk roasts but the difference was not significant. Greater Lulal losses were observed in long, slow cooking of meat than in dry heat methods at a moderate temperature (Funk, Aldrich, and Irmiter, 1966; and Gaines, Perry, and Van Duyne, 1966) . 45 Table 6. Mean scores of cooking loss measurements for ann roasts Cooking losses Source of variation Evaporat on Drip Total % % % Oven Conventional 10. 7 5 9.28 20.03 Electronic 15.62 11. 64 27 .26 Type of heat Dry 17 .78 7.27 25 .05 Moist 8.60 13.65 22.25 Oven x type Conventiona l dry 15.52 5.44 20.96 Electronic dry 20.05 9.10 29.15 Top-of-stove -moist 5.99 13.13 19.12 Elec tronic-moist 11.20 14.18 25. 38 46 Nwnber 4 roasts were slightly larger on the average than nwnber 3 roasts (9.78 lb versus 8.53 lb). Length of cooking time varied with oven as well as with type of cooking, dry or moist. Method 1 which was dry heat roasting in the conventional oven at 250 F required 36.13 minutes per lb while method 4 required the shortest time of 6.55 minutes per lb. Method 4 consisted of cooking with moist heat in the electronic oven. Moist heat cookery proved to be a faster process than dry heat in both electronic and top-of-stove cooking of arm roasts (Table 7). Table 7. Time required for cooking arm roasts by four methods Method Identification Average cooking time mi~lli 1 Conventional dry 36.13 2 Electronic dry 8.45 3 Top-of-stove moist 24.37 4 Electronic moist 6.55 Sensory evaluations. Conventional dry roasted beef arm roasts were judged by the panel to be more flavorful, juicy, and tender than those cooked by the other methods. No significant differences were found in flavor, juiciness, or tenderness as affected by the variables of oven, type, and oven x type interaction (Table 8). However, the taste panel noted a slight difference in flavor as affected by the interaction of oven and type (Figure 5). They preferred the flavor of beef dry roasted. Other researchers have also recorded greater palata- bility scores from meat cooked slowly at a low temperature. Arm roasts were most flavorful when they were cooked by the dry heat method and 47 Table 8 . Mean scores for flavor, juiciness, and tenderness of arm roasts as judged by taste panel Source of Panel scoresa variation Flavor .Juiciness Tenderness Oven Conventional 6.26 6.04 5.78 Electronic 6.06 5.94 5.50 Type of heat Dry 6.22 5.94 5. 70 Moist 6.10 6.04 5.58 Oven x type Conventional dry 6.46 5.89 5. 90 Electronic dry 5. 97 5.98 5. 51 Conventional moist 6.05 6.19 5.6 5 Electronic moist 6.14 5.90 5.50 avalue of 9 indicates most desirable; 1 indicates least des ir able 48 9 8 --Mean 0 6 ·r<.," LJ°,~,, Ll',B,, :l ,..;'" 5 :> '"OJ >, 4 .... 0 U) 3 OJ" "' :; II III IV Method Method I. Conventional oven, dry heat Method II. Electronic oven, dry heat Method III. Top-of - stove cooking, moist heat Method I V. Electronic oven, moist heat Figure 5. Range of sensory eva l uation scores for flavor as a re s ult of method? of cooking ann roasts. 49 obtained a panel score of 6.74, indicating moderately full to ful l flavor according to the weighted adjectives used. The panel reported off flavor as occurring in electronically cooked meat more often than in meat cooked conventionally. Only slight differences in juiciness were found due to oven, oven x type interaction, and to type, i.e., conventional or electronic oven, the com\ination of conventional or electronic cooking with and without moisture, and whether dry or moist heat. The panel scores indi cated that the conventional moist method of top-of-sto ve cooking in a covered roasting pan and the dry oven roasting yielded equally juicy, moist meat. These methods resulted in s lightly more juicy beef than the other two methods. Figure 6 illustrates the variations . These results are also in agreement with the objective test results for juici ness using the succulometer. Average scores by the panel for tenderness did not vary appreciably; samples from three methods were judged neither tough nor tender to slightly tender except in the case of electronic dry roasting which was scored slightly tough (Figure 7). Arm roasts are considered a less tender cut of beef and need long slow cooking to permit collagen to be transformed to gelatin,which process is believed to be initiated at about 60 to 64 C. Longer cooking time near these temperatures would likely have resulted in a more tender product. Rib roasts Objective measurements. The effect of breed and backfat thickness on flavor, juiciness, and tenderness was determined for ntnnber 1 rib roasts. All roasts were cooked at an oven temperature of 325 F and 50 9 -- Mean 8 - - 6.7 0 6 ·.,"rl "'~ rl 5 B,,~·· G · > OJ"' >, 4 >-< 0 OJ"' 3 Cl)" 1 I II III IV Method Method I. Conventional oven, dry heat Method II. Electronic oven, dry heat Method III. Top-of-stove cooking , moist heat Method IV. Ele ctronic oven, moist heat Fig ur e 6. Range of sensory evaluation scores for juiciness as a result of methods of cooki ng arm roasts. 51 9 --Mean 8 0 G; .... 6 ...." - - "'::, .-< 5 .o "'> OJ '' Li - - 4.3 ...:,., 4 0 OJ"' 3 ti)" l I II III IV Method Method I; Conventional oven, dry heat Method II. Electronic oven, dry heat Method III. Top- of - stove cooking, moist heat Method IV. ElectrOnit oven, moist heat Figure 7. Range of sensory evaluation scores for tenderness as a result of met hods of cooking arm roasts. 52 removed at an internal temperature of 155 Fas measured by a potentio meter. Means and standard errors for the four breeds are given in Table 9 and individual data in Table 20. A significant difference associated with breeds was found for tenderness as measured by the Warner-Bratzler shear. Animals from the second genetic group (Shorthorn) exhibited a score of 10.5 lb, the lowest value among the four breeds tested, thus indicating it to be the most tender meat. Group 4 (Shorthorn-Charolais Cross) was the least tender with a score of 18.3 lb according to measurement by the shearing device. The numbers of animals of each breed were unequal. Hereford comprised the largest proportion of animals. The other three breeds were represented by only three animals each. Because of this disproportionate number and a significant difference in tenderness observed according to results of the Warner-Bratzler shear tests, a Duncan multiple range test was utilized to determine significant dif ferences between means among breeds. Results showed that the mean values recorded from the shear test (Table 9) were significantly different. Roasts from Shorthorn-Charolais animals were significantly less tender at the one per cent level, and from Charolais at the five per cent level, than meat of the other two breeds. Ramsey et al. (1963) also utilized this method to determine significan c e in their investigation of palatability differences among seven breeds an Since tenderness is measured as an inverse relation to the numeri- cal value, the least value of 10.5 indicated the greatest tenderness; that is, the Shorthorn rated most tender of the four breeds according Table 9. Mean scores and standard errors of objective and sensory evaluations for number 1 rib roasts Genetic Breed and Backfat Panel scoresa Shear Press forceb fluidc group No. of in Flavor Juiciness Tenderness animals lb ml 1 Hereford, 32 0.77 ± 0.04** 7.0 ± 0.07* 6.8 ± 0.09* 7.5 ± 0.11** 13.5 ± 0.46 7.2 ± 0.57 2 Shorthorn, 3 0.77 ± 0.13** 6.9 ± 0.23* 6.5 ± 0.03* 7,1 ± 0.37* 10.5 ± 1.51** 8.2 ± 1.86 3 Charolais, 3 0.27 ± 0.13 6.0 ± 0.23 5.8 ± 0.03 5.8 ± .0.03 15.8 ± 1.51 6.7 ± 1.86 4 Shorthorn- 0.43 ± 0.13 6.0 ± 0.23 5.7 ± 0.03 5.9 ± 0.37 18.3 ± 1.51 6.2 ± 1.86 Charolais, 3 *Significant (P < .05) **Significant (P < .01) avalue of 9 indicates most desirable; 1 indicates least desirable bLower value indicates more tenderness cHigher value indicates more juiciness ..,, w 54 to this investigation. However, the disproportionate number of animals should be noted. More than three animals per breed are n eeded to make the true significa nce of the findings more valid. These results are in contradiction with those of Stembridge (1968) who determined roasts of the Charolais breed to be most tender and Shorthorn to score consist ently low in all palatability factors from among three breeds. Numbers of animals in her study were also disproportionate with only two Charolais and six Shorthorn animals among the 48 tested. The remaining 40 were Hereford sired. The Shorthorn-Charolais Cross animals were very young in comparison to other animals of this study. Walter et al. (1965) and others have indicated that the meat from young animals is often less tender due to the high proportion of connective tissu e present. Also there is usually little marbling in the young animals. However, investigation by Walter et al. (1965) showed no effect of marbling on tenderness; age of the animal had much more influence. Differences in the amount of press fluid as measured by the suc culo meter were not significant. However, the amount of fluid was greater for group 2 than for any other genetic group. Fat that may have been pressed out of the lean meat sample was in no way separated from the fluid and could have accounted for a small portion of the measured amount. The Shorthorn animals were all graded Choice and had an average backfat thickness of 0.77 inch compared to only 0.27 inch for the Charolais (Table 9). No significant differences were indicated for number 2 rib roasts as affected by oven, bone, and oven x bone interaction . Oven refers to 55 use of conventional and electronic ovens. One-half of the roasts had been boned and tied, and bone refers to whether or not the roast had been boned before cooking. Slight differences were noted for shear determinations as influenced by oven and for press fluid measurements by both oven and oven x bone interaction (Tables 10 and 21). Shearing force was greater for meat cooked electronically (17.2 lb versus 15.2 lb). Some cores were more tender than others, and the range of varia bility is represented in Figure 8. Tenderness varied from animal to animal. This observation is in agreement with other studies which have demonstrated differences in tenderness due to age and breed as well as to method of cooking. According to the data as given in Table 10, more press fluid was obtained from meat cooked conventionally than from meat cooked electron ically. Electronically cooked meat tended to be more dry and more fully cooked; i.e., a higher final internal temperature was reached on standing which resulted in a more "done" stage for the meat. Boned meat cooked conventionally and unboned meat cooked electronically yielded more press fluid than the other two methods. Figure 9 shows the variation of amounts of press fluid obtained from the meat samples of the four different cookery treatments. Cooking losses. Ntnnber 1 rib roasts consisting of the ninth, tenth, eleventh, and twelfth ribs from four breeds averaged 8.94 lb in size and required an average of 31.6 minutes per lb to attain the desired degree for medium Table 10. Mean scores of objective measurements for number 2 rib roasts Source of Shear Press variation fore ea fluidb lb ml Oven Conventional 15 . 22 6.68 Electronic 17 ,1 8 5 . 54 Bone Unboned 16 .40 5. 72 Boned 16.00 6.52 Oven x bone Conventional unboned 15.69 5.43 Electronic unboned 17 .11 6.00 Conventional boned 14.76 7.94 Electronic boned 17.24 5.09 8 Lower value indicates more tenderness bHigh er value indicates more juiciness 57 26 --Mean 24 22 20 18 "',-< 16 • 14 LJ,,,~,, U' ,~ ,, 12 Q)'" .c"' 10 "' 8 6 4 2 I II III IV Method Method I. Conventional oven, unboned Method II. Electronic oven, unboned Method III, Conventional oven, boned Method IV. Electronic oven, boned Figure 8. Range of Warner-Bratzler shear values for tenderness as a result of methods of cooking number 2 rib roasts. 58 15 14 --Mean 13 12 11 ....1 s. .... 9 "'::, 8 - - 7. 9 ...... 7 (/) 6 - - 6 . 0 (/) 5 - - 5. 4 p..'"... 4 3 2 I I II III I V Metho d Method I. Conventional oven, unboned Method II. Electronic oven, unboned Method III, Conventional oven, boned Method IV. Electronic oven, boned Figure 9. Range of press fluid values as a result of meth ods of cooking number 2 rib roasts. 59 and varied slightly with breed (Table 11). These standing rib roasts were cooked at 325 F to the same internal temperatur e of 155 F. Evapor ative losses contin ued during the standing period following removal from the oven as the internal temperature continued to rise. The average rise in temperature for all roasts was 11.1 F. Losses among the number 2 roasts varied greatly (Tab l_e 12). The data indicate that oven, presence or absence of bone, and interaction of t hese variables exert a significant influence on the total cooki ng lo sses . Considerably greater total losses (39 per cent versus 28 per cent) were recorded for electronic cooking of the rib roasts than for co nventional roasting in the electric oven. Presen ce or absence of bone showed little effect on cooking losses. The oven x bone interaction demonstrated the adverse effect of electronic cookery regardle ss of whether or not the roast contained bone. Mean total losses were 39 per cent in electronically cooked roasts with bone and 40 per cent in boned roasts. This disagrees with an e arly investigation by Apgar et al. (1959), using microwave energy, which failed to show any signifi cant differences in total cooking losses due to cooking method . Work done by Kylen et al. (1964) demonstrated the adverse effects of electronic cooking on beef and pork roasts. They found the mean total losses greater though the cooking times were much less than for conventional gas oven ro asti ng. Funk, Aldrich, and Irmiter (1966) recommended conven tional roasting of beef at a moderate oven temperature to minimize total cooking losses. Internal Raw Cooking Cooking losses Genetic Backfat Breed weight time group in Evaporation Drip Total gm min % % % 1 Hereford 0. 765 4001. 56 282.94 14.86 9.90 24. 76 2 Shorthorn o. 767 4826.67 308.33 14.70 13.61 28.31 3 Charolais 0.267 4143.00 280.00 17. 43 5.78 23. 21 4 Shorthorn- 0.433 3772.67 260.00 16.30 7.13 23.43 Charolais "'0 62 without sacri f icing out er edge ti ss ues. Prev i ous researchers have experienced simila r difficu lti e s in cooking large roasts electroni cally. It was necessary to tur n the roast seve r a l t imes during cooking in an attempt to obtain more eve n penetration of microwaves and lessen surface drying. Even though considerable attention was given to turn ing the meat for more even bombardment of the microwaves, the drying effect was apparent. Figures 10 and 11 illustrate the difference in appearance of number 2 rib roasts when cooked by conventional and electronic methods . Sensory evaluations. The data indicated highly significant dif ferences for flavor, juiciness, and tenderness of number 1 rib roasts as evaluated by t he taste panel members (refer to Table 9). Genetic groups 1 and 2 (Hereford and Shorthorn) were judged more flavorful, juicy, and tender than the other two breeds considered. These findings are contradictory to those of Stembridge (1968) who found a trend for Charolais to be the most tender, juicy, and flavorful of all breeds tested. Meat of the Charolais breed was scored by the panel in t his study to be slightly more juicy but also slightly less tender than the cross breed of Shor t horn - Charolais . High l y s i gni ficant diffe r ences wer e indicated for juiciness and tender ness and a signi f i ca nt diff ere nce in f l avo r for number 2 roasts gi ven fo ur treat ments (Tabl e s 13 an d 14 ) . The Charolai s meat scored l owe st in f lavor an d was least tender. The ov en showed a s i gnificant in f luen ce on jui c iness with a mean panel s core of 6 . 6 f or co nve n t i ona l cooking compar ed to 6.2 for electr oni c cookin& in dicatin g gr ea t er j ui ci nes s f or t he form e r cooking method . 63 r Figure 10. Number 2 rib roast cooked conventionally at 325 F to an internal temperature of 155 F. Figure 11. Number 2 rib roast cooked electronically to an internal temperature of 140 F. 64 Table 13. Mean scores of sensory measurements for number 2 rib roasts Source of Panel scoresa variation Flavor Juiciness Tenderness Oven Conventional 6 . 86 6.62 7.06 Electronic 6.58 6 . 18 6.18 Bone Unboned 6.80 6 .5 2 6.80 Boned 6.64 6.28 6.42 Oven x bone Conventional unboned 6.98 6.66 7.17 Electronic unboned 6.63 6.38 6.42 Conventional boned 6.75 6 . 59 6.96 Electronic boned 6.53 5 .9 8 5.88 avalue of 9 indicates most desirable; 1 indicates least desirable 65 Table 14. Analysis of variance for ntnnber 2 rib roasts due to oven, bone, and oven x bone interaction Sour ce of Degrees of Panel scores varia tion freedom Flavor Juiciness Tenderness Blo cks 9 Oven 1 81.2* 198.0** 837.2** Bone 1 27.2 55.2 140 . 6 Oven x bone 1 4.2 27.2 27.2 Error 27 18.9 21.3 89.5 Total 39 *Significan t (P < .05) **Significan t (P < .01) 66 Figures 12, 13, and 14 illustrate the effect of cooking methods on taste panel evaluations. The ranges in flavor and juiciness values showed little fluctuation, but scores for tenderness varied widely with method of cooking. Electronically cooked meat exhibited much less tenderness than conventionally cooked beef according to the taste panel. Effect of bone The samples of cooked meat taken from next to the bone in both con ventional and electronic cooking methods showed some variations in mois ture losses (Figure 15). The electronically dry-cooked arm roasts and unboned number 2 rib roasts contained less moisture than any of the other roasts. This finding indicated that the bone in these roasts did influence the degree of waves into the surrounding muscle, thus making it more well done . Hence, it would suggest that a more evenly done piece of meat is obtainable by electronic cooking if it contains no bone. It should be noted that moisture values for the conventional dry and top-of-stove moist-cooked arm roasts and the conventionally roasted unboned number 2 rib roasts were almost identical . The manufacturer of the electronic oven used suggested that the presence of bone hinders penetration of microwaves. The meaning is not clear and would suggest that the waves do not penetrate bone but may be deflected into the muscle with resultant increased degree of Indeed, the results indicate the meat to be more done (dry) next to the bone in the electronic cooking method of this study. It should be noted, however, that the ri se in te mpera tur e after removal from the oven reached a greater maximum in electronically cooke d meat than in that 67 9 --Mean 8 0 6 6 "0 D, D Ll,' "M 6 B" u rl"' " 5 :> aJ"' :>, ... 4 0 UJ aJ UJ" 3 2 1 I II III IV Method Method I. Conventional oven, unboned Method IL Electronic oven, unboned Method III. Conventional oven, boned Method IV. Electronic oven, boned Figure 12. Range of sensory evaluation scores for flavor as a result of methods of cooking number 2 rib roasts. 68 9 8 --Mean 6:7 B- - 6 .4 B-6.6 B []6.0 2 1 I II III IV Method '1ethod I. Conventional oven, unboned Method II. Electronic oven, unboned Method III. Conventional oven, boned Method IV. Electronic oven, boned Figure 13. Range of sensory evaluation scores for jui ciness as a result of methods of cooking number 2 rib roasts. 69 9 --Mean 8 07.2 0 6 0 ~' ' ·ri..," -- 6.4 g, 5 .-<""' ;, 1 I II III IV Method Method I. Conventional oven, unboned Method II. Electronic oven, unboned Method III. Conventional oven, boned Method IV. Electronic oven, boned Figure 14. Range of sensory evaluation scores for tenderness as a result of methods of cooking number 2 rib roasts. 70 Arm roasts Top-of-stove moist 1 6 Conventional dry 64 Electronic moist 63 Electronic dr y I 60 Number 2 rib roasts Conventiona l unbon e r 6 Electronic unboned 59 0 10 20 30 40 50 60 70 Per cent moisture loss Figure 15 . Per cent of moisture loss from meat adjacent t o the bone. 71 which was conventionally cooked (167 F versus 162 F). It would appear there is not enough information to make a valid conclusion of the effect of bone on surrounding muscle during the cooking process. Correlations Arm roasts. Correlation coefficients for arm roasts are given in Table 15. Tenderness correlated positively with juiciness and flavor as judged by the taste panel . The high correlation value of r = .78 for flavor and r = .66 for juiciness indicated that as tenderness increased, the flavor and juiciness were also increased and received higher scores. Correlation between tenderness measurement by the Warner-Bratzler shear method and as judged by the taste panel was r = -.57. This indi cated that as beef was found to be more tender by the shear nethod, it was also judged more tender by the panel. Low shear values indicated more tenderness whereas high panel scores indicated more tenderness. This inverse relationship of the two tests resulted in the negative high correlation. Tenderness as judged by the taste panel showed high correlation with total cooking losses (r = .58). Tenderness decreased when cook ing losses were high . Correlation coefficients were also significant for total cooking losses with flavor and juiciness, being -.62 and -.69 respectively . Greater cooking losses caused a decrease in both flavor and juiciness scores. Backfat thickness did not appear to be associated with tenderness, flavor, or juiciness (r = .02, .03, and -.03). Table 15. Correlation coefficients for sensory and objective tests, total cooking loss, age, and backfat thickness for arm roasts Shear Press Total Backfat Panel scores Age Factor force fluid cooking thickness Flavor Juiciness Tenderness lb ml loss% mos in Flavor . 78** .78** -.46*'' .27;, -.62** .1 6 .03 Juiciness .66** - .28* .4 7''* -. 69*1< .1 0 -.03 Tenderness -. 57>'<* .19 -.5 8** , . 09 . 02 Shear force .04 .12 -. 32* .02 Press fluid -.40** -.23 -.20 Tota l cook- ing loss -. 002 - . 03 Age .36** *Differences significant (P < .05) *~'tDifferences significant (P < .01) "N 73 The correlation between flavor and juiciness was high, r = .66. The value of r = .47 for press f l uid showed a positive relationship of the objective method with sensory evaluation for juiciness. This find ing appeared to indicate that as juiciness increased, flavor was enhanced according to the j udgment of the taste panel members. ~ of animal appeared to be significantly related only to shear v force values (r = . 32) and to backfat thickness (r = .36). Thus, as age of animal increased, the meat was more tender for the animals of this study; the amount of backfat also increased with age. Correlation coefficients above .26 and .34 were necessary to be significant at the P < . 05 and P < .01 respectively. Rib roasts . Correlation coefficients for number 1 rib roasts are given in Table 16. Correlation among scores by the taste panel for flavor, juicines s , and tenderness were highly significant, indicating that the three are closely related . Flavor and juiciness exhibited an r value of .71; tenderness and juiciness, r = .59; and flavor and tenderness, r = .61. These correlations indicated that more tenderness and jui c iness resu l ted in greater enhancement of flavor. The Warner-Bratzler shear value was highly correlated (r = .62) with tenderness as scored by the taste panel . This finding also occurred with the arm roasts. Press fluid exhibited no significant correlation with any of the other factors; the values ranged from r = .04 tor= .22 . Juiciness as ju dged by the t aste panel correlated with total cook ing losses with a somewhat lowe r r value (- .31) than found for the arm roasts (-.69). Table 16. Correlation coeff icients for sensory and objective tests, total cooking loss, age, and backfat thickness for number 1 rib ro as ts Panel scores Shear Press Total Backfat Age Factor force fluid cooking thickness Flavor Juiciness Tenderness lb ml loss% mos in Flavor . 71** .61** -. 12 .04 . 17 .42*''' .43** Juiciness .59** - .14 .19 -,31;, .35* . 44** Tenderness - .62** .OS .01 . 33* .27 Shea r force .OS - .20 -.34* - .07 Press fluid -.22 .06 -. 20 Total cook- ing loss .40** .13 Age .51** *Differences significant (P .05) **Differences si gnificant (P < .01) ,,_.__, 75 The high correlation coefficients with all factors except press fluid for age indicated that a}~ of animal exerts a definite influence on beef palatability, particularly flavor. A value of r = .40 for total cooking loss with age seemed to indicate that the older the ani mal the greater the cooking loss. The increase in backfat (r = .51) with age may account for the greater cooking losses . Backfat thickness correlated positively with taste panel s cores for flavor, juiciness, and tenderness. Values of .43 for flavor and .44 for juiciness indicated that as backfat thickness increased, the panel members rated the beef more flavorful and more juicy. With an r value of .27 for tenderness there was no significant relation between backfat thickness and tenderness, but tenderness showed a significant relationship to age (r = .33). Values of at least .31 and .40 were necessary for the correlation coefficients of both number 1 and number 2 rib roasts to be significant at P < .05 and P < .01 respectively. Correlation coefficients for number 2 rib roasts are given in Table 17. Tenderness, juiciness, and flavor showed a highly significant relationship as judged by the taste panel with correlation coeffi c ients above .60. A value of r = .63 for flavor with relation to juiciness indicated more flavor present when the meat was more juicy. The negative value of r = -.48 was obtained for the correlation between taste panel-judged tenderness and that by the Warner-Bratzler shear. Again the two methods of judging tenderness were equally efficient in measuring tenderness. Table 17. Correlation coefficients for sensory and objective tests, total cooking loss, age, and backfat thickness for number 2 rib roasts Panel scores Shear Press Total Backfat Factor force fluid cooking Age thickness Flavor Juiciness Tenderness lb ml loss% mos in Flavor .63** .59*'' -.16 -.10 -.25 -.18 .32* Juiciness .61** -.005 .18 -.SO** -.21 .15 Tenderness -.48'"' .01 - . 36* .10 .20 Shear force -.03 .13 -.20 -.22 Press fluid -.26 - .06 -.24 Total cook- ing loss .18 . 22 Age . 50** *Differences significant (P < .05) * 1'cDifferences significant (P < .01) ..._, (7, 77 Press fluid did not show any high correlations with any of the factors. Total cooking losses showed a negative correlation to taste panel scores for juiciness (r =~50) and tenderness (r = -,36). This rela tionship indicated that as losses increased, the juicin ess and tender ness of the roast beef decreased. Correlation coefficients varied for age with each of the other factors but only with backfat thickness was there any significant relationship (r = . 50). Backfat thickness appeared to be significantly related only to flavor (r = .32) and to age . Other correlation coefficients varied from .15 t o -.24. 78 COMMENTSAND CONCLUSIONS The effect of breed, backfat thickness, and methods of cooking on the quality of beef roasts was studied as another phase of a continuing comprehensive study of beef. Cooking temperature and breeding effects had been previously studied by Jenson (1966) and Stembridge (1968). There was a disproportionate number of animals of each breed in the present study. Thirty-two of the 41 animals were Hereford. The remainder were equally divided among Shorthorn, Charolais, and Shorthorn Charolais Cross. Warner-Bratzler shear determination indicated breed of animal sig nificantly influenced the tenderness of number 1 rib roasts cooked at 325 F to an internal temperature of 155 F. Roasts from animals of the Shorthorn breed were rated most tender, in comparison to the other breeds of Hereford, Shorthorn-Charolais, and Charolais, which was the least tender. However, having only thre e Shorthorn animals in the study was probab l y not truly representative of the breed. The method of cooking number 2 rib roasts and arm roasts influenced the tenderness to some extent, but not significantly. Moist heat and electronic cookery resulted in higher shear force determinations, hence, less tenderness in these cuts . In contradict ion, studies by Headley and Jacobson (1960) indicated shear test values were not related to cooking method. Differences may have been from other factors or condi tions such as size of roast, time in the oven, or evaporation losses. According to taste panel judgment, conventional dry heat is more 79 desirable than electronic cooke ry to produce good flavor, juiciness, and tenderness. The statistical analyses of the arm roasts did not consider the effect of breed of animal in the design of partial confounding. Press fluid varied in the amounts available from the same sized sample from different roasts. A significant difference was noted only in the arm roasts as a result of type of cooking. The type referred to whether meat was cooked by moist or dry heat. Roasts cooked by moist heat held greater moisture and were evaluated by panel members to be slightly more juicy than roasts cooked by dry heat. But fluid measurement did not seem to be always related to the degree of cooked roasts there was evidence of unevenness of cooking. The color of the press fluid was noted . Color range was from blood red to shades of lighter red and pink and finally a pale beige which usually indicated the meat had registered above 165 Fas its maximum internal temperature. The lighter the color of the press fluid generally indicated that the internal temperature had risen higher after removal from the oven. No record was kept for rise in temperature after arm roasts cooked conventionally were removed from the source of heat since no appreciable rise was found in the preliminary study. But electronic cookery of arm roasts resulted in an internal temperature rise of 10 to 15 F during the standing time after removal from the oven. For this reason end point temperature for conventional cooking was 160 F and for electronic cook ing, 150 F. 80 The average rise of internal temperature for rib roasts was 7.6 F for number 1 rib roasts and 7 . 4 F and 7.7 F for unboned and boned number 2 rib roasts respectively. These cuts were all roasted to an internal temperature of 155 Fas measured by the potentiometer in a 325 F oven. Number 2 rib roasts were removed from the electronic oven at an internal temperature of 140 F since the temperature continued to rise 15 to 35 degrees on standing. The average rise was 27.0 F for unboned and 26.6 F for boned roasts cooked by microwave activity. The meat of electronically cooked roasts was considered more thoroughly cooked at the 140 F plus the standing temperature rise than the roasts cooked conventionally. It is recommended that the meat should be removed from the electronic oven at a two or three degree lower temperature than 140 F to prevent overcooking. Several difficulties were encountered in electronic cookery of both arm and rib roasts. The roasts were too large for proper penetra tion of the microwaves in the household size electronic oven before drying and crusting appeared on surface edges (see Figure 11). Arm roasts were turned once during cooking. It was necessary to turn rib roasts three times to expose the four surfaces to the bottom of the pyrex pan and oven where the cooking appeared to be more intense. The l ar ge size of the roasts probab l y i nterfered with scatter~ng and reflecting of mic rowaves from ove n sides and top. An operator needed to be on hand co ns t an tly dur i ng ele c t ron i c cook in g because the oven was t imed in minu tes t o a maximum of 28 . Most rep l ica t ions needed more t ime tha n 28 mi nutes t o complet e t he cooki ng process . 81 The author would reconunend t ha t roasts cooked in the electronic oven be given a standing per i od about half-way through the estimated cooking time to allow equaliza t ion and penetration of heat. Then the meat should be again exposed to the microwave activity to a desired endpoint and the final standing time allowed before serving. Electronic cooking is not reconunended for arm roasts. The shortened cooking time does not allow for softening of the connective tissue. The Biceps brachii muscle contains much connective tissue and is not truly representative of the edible portions of arm roasts. It is recommended that this muscle not be used as a core sampling area in future studies. Determination of the effect of bone to Results of this study show that some of the factors influencing palatability can be controlled, but other factors have already been determined before the meat is purchased. The homemaker must thus decide on the method of cooking to obtain the most desirable and palat- able beef roast as judged by her family. 82 SUMMARY The effect of breed, backfat thickness, and methods of cooking on quality of beef arm and rib roasts was studied. Four breeds, Hereford, Shorthorn, Charolais, and Shorthorn-Charolai~were represented. There was a highly significant difference in backfat thickness, with Hereford and Shorthorn animals having the largest amount which still measured less than one inch. The Charolais had a mean backfat thickness of less than one-fourth inch, but they were also the youngest animals, being just 11 months old. All roasts of the ninth, tenth, eleventh, and twelfth ribs were cooked at 325 F to an internal temperature of 155 Fas measured by a potentiometer in a thennostatically controlled electric oven designed for meat research. Warner-Bratzler shear results indicated Shorthorn animals to be the most tender and Charolais to be the least tender, but an experienced taste panel judged Hereford to be the most tender, in addition to being the most juicy and flavorful of the four breeds tested. Roasts of the sixth, seventh, and eighth ribs were cooked conven tionally as well as electronically. One-half the number were boned before roasting. No significant differences were found in tenderness or juiciness as measured by objective tests. More juice was pressed from conventionally cooked roasts than from electronically cooked ones. Differences in taste panel scores showed that meat roasted in the con ventional oven rated significantly more tender and more juicy (at the 1 per cent level) and more flavorful (at the 5 per cent level) than in 83 the electronic oven. Meat cooked in the conventional oven as compared to that cooked by microwave activity was rated more desirable. Greater total cooking losses were recor ded when meat was cooked elec tronically, 40 per cent for electronically cooked meat as compared to a high of 28 per cent for conventional cooki ng. Arm roasts cooked by dry and moist heat by both conventional and electronic metho ds showed significant differences in the amount of juiciness measured objectively using a succulometer. Moist heat cook ing resulted in the greatest amount of press fluid. Meat cooked by microwave activity was less tender requiring greater shearing strength to shear a one-inch core . Electronically cooked beef was less juicy, tender, and flavorful than conventionally cooked meat according to the panel of judges. Though cooking time was much less in electronic cooking, total cook ing los ses were higher. Factors that showed a relationship giving high correlation coeffi cients were as follows: taste panel scores for flavor, juiciness, and tendernes s; Warner-Bratzler and taste panel scores for tenderness; press fluid values and taste panel scores for juiciness; total cooking losses and taste panel scores for juiciness and tenderness; age and Warner-Bratzler shear values; and backfat thickness and flavor scores. 84 LITERATURECITED Adams, R., D. L. Harrison, and J, L, Hall. 1960 . Comparison of enzyme and Waring blendor methods for the determination of colla gen in beef. Journal of Agricultural and Food Chemistry 3:229-232. Allaire, Royal P . 1966. 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Hiner. 1953. Variability and heritability of tenderness and its relationship to other beef characters. Journal of Animal Science 12:904. (Abstract) Zaika, Laura L., A. E. Wasserman, C. A. Monk Jr., and J. Sa1ay. 1968. Meat flavor. 2. Procedures for the separation of water-soluble beef aroma precursors. Journal of Food Science 33:53-58. Ziegler, P. Thomas. 1968. The meat we eat. 9th Edition. The Inter state Printers and Publishers, Inc., Danville, Illinois. 547 p. 92 APPENDICES 93 Appendix A Tables Table 18. History of animals Backfat Calf Dam Sire Birth Breed Slaughter Grade thick- date date ness in 3E 1328 P7 4/9/67 Hereford 11/18/68 Choice 0.6 SE 8A P7 4/10/67 Hereford 11/18/68 Choice 0.8 !OE Hoffman Hoffman 4/16/67 Hereford 11/18/68 Choice 1.0 57E H60 G57 3/15/67 Shorthorn 11/18/68 Choice 0.8 59E L58 51B 3/16/67 Shorthorn 11/18/68 Choice 0.8 63E H52 51B 3/28/67 Shorthorn 11/18/68 Choice 0.7 151E 102C 594 4/28/67 Hereford 11/18/68 Choice 0 . 6 18D 14B Dwarf 4/15/66 Hereford 3/13/68 Prime 1.5 136D 164B 0133 5/28/66 Hereford 3/13/68 Prime 0.9 14C 20A Dwarf 4/23/65 Hereford 3/13/68 Prime 1.3 155D Gl04 Ll09 5/11/66 Hereford 3/13/68 Choice 1.0 157D Kl06 0133 5/15/66 Hereford 3/13/68 Choice 0.8 1610 Kl08 0133 5/28/66 Hereford 3/13/68 Choice 1.1 Brand II No. Ch 1/2 376 500 7/13/67 Charolais 1/29/69 Good 0.4 6E E20 P7 3/28/67 Hereford 1/22/69 Choice 0.7 119E Mll2 Ll09 4/17/67 Hereford 2/12/69 Choice 0.8 llOE 0128 594 4/19/67 Hereford 3/3/69 Choice 0. 6 155E JS Ll09 4/30/67 Hereford 5/12/69 Choice 0.9 123E 8124 594 4/20/67 Hereford 5/12/69 Choice 0.7 143E Ll08 594 4/24/67 Hereford 5/12/69 Choice 0.8 157E El20 594 5/7/67 Hereford 5/12/69 Good 0.7 161E Gl20 Ll09 5/25/67 Hereford 5/12/6 ,9 Choice 0.6 12E Shupe Brae- 4/13/67 Hereford 5/12/69 Choice 0.8 Arden 16E 4B P7 5/11/67 Hereford 5/12/69 Choice 0.9 112E Gll2 Ll09 4/19/67 Hereford 5/10/69 Choice 1.1 122E MllO Ll09 4/25/67 Hereford 5/12/69 Choice 0.6 124E Bll4 594 4/25/67 Hereford 5/12/69 Choice 0.9 Brand II No. Ch Ill 383 500 7/4/67 Charolais 9/23/68 Standard 0.2 71F H60 Charolais 6/23/68 Shorthorn- 5/12/69 Good 0.4 Charolais 94 Table 18 . Continued Backfat Slaughter Calf Dam Sire Birth Breed Grade thick- date date ness in 67p N56 Charolais 4/28/68 Shorthorn- 4/23/69 Good 0.3 Charolais lF Hl2 105D 3/1/68 Hereford 5/4/69 Choice 0.4 13F M2 105D 4/2/68 Hereford 5/7/69 Choice 0.5 SF El2 105D 3/10/68 Hereford 5/14/69 Choice 0.5 l ?F F2 105D 4/9/68 Hereford 5/11/69 Choice o. 7 23F 6B 105D 4/16/68 Hereford 5/11/69 Choice 0.6 30F 4C 105D 4/24/68 Hereford 6/25/69 Choice 0.8 21F 34A 105D 4/15/68 Hereford 5/28/69 Good 0.4 73F Lost Charolais 7/3/68 Charolais 5/25/69 Standard 0.2 tag 8336 26F 28A 105D 3/26/68 Hereford 5/21/69 Choice 0.8 llF 1308 105D 3/24/68 Hereford 5/28/69 Choice 0.6 69F H54 Charolais 6/22/68 Shorthorn- 5/12/69 Choice 0.6 Charolais Table 19. Individual data for arm roasts Panel scores Animal Shear Press Cooking loss Breed Method Roast number Flavor Juiciness Tenderness force fluid Drip Evap Total lb ml % % % Hereford 1360 1 3 7.2 7.2 7.9 17.8 0.9 4.6 15.1 19.7 3E 1 3 6.8 6.1 7.1 13.4 1.2 7.5 14.8 22.3 180 1 4 6.7 6 .3 6.3 21.5 1.0 4.8 13.4 18.2 1550 1 4 5.9 4.5 5.8 17.2 2.1 6.2 13.4 19.6 123E 1 3 7.2 7.2 7.2 13. 9 6.3 6.6 15.6 22.2 155E 1 4 4.9 4.8 5 . 7 18.6 0.7 10.9 15.7 26.6 151E 1 4 6.5 6.5 7 .0 17.5 2.0 3.3 18.4 21. 7 143E 1 3 6.5 5.6 6.6 16.7 2.0 3.9 19.4 23 . 3 6E 1 4 6.5 7.4 6.7 22.4 2.4 4.7 12. 9 17.6 lOE 1 3 7, 7 7.4 7.4 15.1 3.5 4.2 15.3 · 19. 5 112E 1 3 6.6 6 .9 6.4 18.6 8.0 6.3 12 .4 18.7 lF 1 4 6.6 5 . 8 5.8 21. 7 1. 0 4.8 19. 9 24.7 1570 2 4 6.1 5.0 5 . 9 19.6 1.6 10.1 20.4 30.5 1610 2 4 6.7 6.0 6.1 17.4 1.1 8.0 20.0 28.0 5E 2 3 5.2 4.5 3.0 16.0 0.8 8.9 18. 8 27.7 14C 2 3 5.6 5.4 5.3 18.1 1.3 9.2 23.1 32 .3 119E 2 4 5.4 5.9 2.6 30.4 1.4 7.3 18.3 25.6 llOE 2 3 5 . 3 4.1 3.4 20.6 1.5 11.2 22.6 33.8 155E 2 3 4.9 5.9 3.7 17.4 1.0 11.9 19.1 31. 0 157E 2 4 5 . 5 5.3 5.0 24.1 4.0 9.6 19.5 29.1 124E 2 3 5.6 4.4 3.3 27.7 1.1 8.0 23.0 31.0 6E 2 3 4 . 9 4.7 4.2 22 .9 0.5 8.3 23.0 31. 3 lOE 2 4 5.6 5.6 4.6 24.5 5.7 9.8 18.6 28.4 112E 2 4 5.6 4.8 4.3 23.3 2.8 10.0 20.5 30 . 5 113F 2 4 4.9 5.1 4.7 23 . 3 3.9 7.3 18.1 25 .4 1570 3 3 6.8 7.2 6.0 23.9 3.5 8.3 10.8 19.1 '°v, 1360 3 4 7.4 5.9 6.0 23.2 2.0 10.8 7.5 18. 3 3E 3 4 6.9 6.7 6.4 13.8 1. 6 15.8 7 . 5 18.3 Table 19. Continued Panel scores Shear Press Cooking loss Animal force fluid Breed Method Roast Flavor Juiciness Tenderness Drip Evap Total ntmlber l b ml % % % Hereford 18D 3 3 6 . 4 5 .9 5.6 22.8 2.9 7 .0 7.9 14 . 9 119E 3 3 5.4 6.0 3 . 7 23.9 2.3 11.9 8.5 20 . 4 HOE 3 4 7.1 6.6 5 . 3 19.1 9.9 12 . 7 5 . 8 18.5 161E 3 4 6.8 6.6 7 .0 16.1 2.5 16.1 5.1 21. 2 151E 3 3 7.2 8.0 6.9 15.6 4.9 12 . 7 3.2 15.9 124E 3 4 6.2 5.8 4.9 19.9 0.9 16.2 4.8 21.0 16E 3 4 6.1 6 . 4 5.6 19. 8 8.2 11.5 4.9 16.4 12E 3 3 6.8 6.9 7.5 20.8 4.8 15.4 4.6 20 .0 122E 3 4 5.7 5.6 5 .9 23.8 3.2 18.2 3.5 21.1 lF 3 3 5 . 6 6.4 5.6 23.2 7.8 13.3 5 . 2 18.5 1610 4 3 5.7 5 .1 5. 6 14.2 0.8 5 .1 27.7 32.8 SE 4 4 6.4 5.7 5.3 15. 4 2.2 10.3 17.4 27.7 14C 4 4 5.6 5.6 5.3 21.3 1. 6 9. 4 12.7 22.1 1550 4 3 5.9 6.0 4.5 18.6 4.4 10.5 12.9 23 .4 123E 4 4 7. 7 6.5 6.3 17 .4 6.6 15.5 9.0 24.5 161E 4 3 6.4 6.4 4.9 18.4 1.5 16.7 9.3 26.0 157E 4 3 6.5 6.8 5.5 20 .5 7,2 18.3 3.2 21. 5 143E 4 4 6.0 5.1 5.4 19.8 2 . 8 17.7 8.1 25.8 16E 4 3 6.0 5.0 4.5 19.2 1.1 18.0 5.4 23.4 12E 4 4 5.6 5 .2 4 . 8 22 . 5 1. 0 17.7 6.1 23.8 122E 4 3 5.7 5.2 3.8 23.6 1. 7 19.2 8.5 27.7 13F 4 3 5.7 6 .5 5.1 22.7 3.7 20.8 3 . 1 23.9 Shorthorn 57E 1 4 7.4 7 . 2 6.5 17.2 2.5 5.8 12.1 17.9 59E 1 3 7.8 8.1 7.3 17.0 8 .1 5.1 15.2 20.3 '° 59E 2 4 5.7 5.3 5.2 14.9 1. 0 6.9 20.4 27,3 "' 63E 3 4 6.5 6.2 6.2 16.5 0.9 12.4 6.7 19.1 Table 19. Continued Panel scores Shear Press Cooking loss Animal Breed Method Roast force fluid Drip Evap number Flavor Juiciness Tenderness Total lb ml % % % Shorthorn 57E 4 3 6.6 6 .5 5.0 18.4 2.3 8.7 15.9 24. 6 63E 4 3 5.2 4.7 4.2 25.5 1. 9 10.2 17.0 27.2 Charolais Chill 1 4 6. 8 6 .1 7.2 14 .6 2.9 2.9 19.1 22.0 Chl/2 2 4 5.6 6.0 3.8 25.5 7.6 9.9 15.4 25.3 Ch/12 3 3 6.0 6.0 5.2 20.4 8.9 14.7 6.5 21.2 Chill 4 3 5.6 4.6 4.8 17.8 3.4 14.6 11.6 26.2 __,'D Table 20. Individual data for ntm1ber 1 rib roas t s Cooki ng lo s s Animal Treat- Pane l scores Shear Pre ss. Breed force fhdd Drip Evap Total number rnent Flav or Ju iciness Tender ness lb ml % % % Hereford 1570 325F 7. 4 7 .4 7.4 12.4 4.1 9. 7 14.3 24 . 0 1360 7. 3 7. 2 7.9 11.6 5 . 9 10 . 5 13.3 23.8 151E 6.7 7 . 0 7. 8 12 . 2 6. 5 5.6 15.2 20 . 8 lOE 6 . 2 6. 2 7.4 12 . 6 4 . 8 11. 7 15.1 26.8 14C 7 .4 7.6 7 . 6 16 , 7 6. 2 9.8 10.2 20.0 1610 7. 3 7. 4 7. 7 14.2 5.2 6.5 17.0 23.5 1550 6. 9 7.0 7 . 2 17.4 7 . 2 10.9 12.5 23 . 4 SE 6. 6 6.8 8. 0 11.2 11.0 9.0 14.1 23.0 180 6 . 6 6 . 3 6 .4 15 . 4 3 , 7 12.3 11. 9 24 . 2 3E 6 . 6 7 . 4 7 . 8 9.1 5.9 10.2 14.0 24.2 6E 7 . 2 7 . 0 6 . 3 14 . 8 10.9 10.2 12.9 23 . 1 HOE 6 . 0 6. 0 7.2 10 . 2 9.9 13 . 3 15.1 28.4 119E 7. 3 6 . 8 7 . 0 14.4 7.1 10.4 15.7 26 .1 123E 7 . 1 6. 0 7 . 6 12 . 6 1.5 13.3 16.3 29 . 6 112E 7. 4 6.9 7. 6 15.9 15.5 13 . 9 13.2 27.1 157E 6 . 8 5 . 8 7.3 16 . 7 8 .5 11 . 0 17.2 28.2 161E 7.0 6 . 8 8 . 0 12 .0 13 . 4 9.3 15.4 24.7 155E 7.5 7 . 0 7.8 12 .4 5 . 6 16.6 16.9 33 . 5 143E 7.4 6 . 1 7.0 17 . 8 4 .1 10.6 17 . 6 28 . 2 lF 6.6 6.5 6.4 16. 4 10 . 4 5. 4 14.9 20.3 12E 7 . 2 6.3 7.7 10.4 4.0 12. 8 15.3 28.1 16E 7. 3 7.6 8.2 13 . 4 13 . 0 10. 6 11. 5 22.1 124E 7 . 3 7. 0 7. 4 14. 7 8 .3 13. 4 13 . 0 26.4 122E 7.2 7.0 8 .1 13 . 3 4. 7 12. 8 15 . 2 28.0 13F 6.8 7 . 0 8 .1 11 . 9 4 .9 4 . 8 15 . 9 20. 7 SF 7.2 6. 7 8 .1 16 .2 7 .6 7.9 16.8 24,7 '°00 llF 7.3 6. 6 7 . 9 12 . 3 8 .0 6 . 3 17 . 5 23.8 30F 6 .4 6.6 7.9 13 .6 3 .1 11. 5 13. 6 25.1 Tabl e 20. Conti nued Cooking lass Panel scores Shear Press Br eed Animal Treat- force fluid Drip Evap Total number ment Flavor Juiciness Tenderness lb ml % % % Her eford 21F 325F 7.0 6.6 7.6 13. 9 8.6 5 .6 14. 8 20 . 4 17F 6.9 6 . 3 6.7 13 .8 4. 5 9.2 15.2 24.4 23F 6.8 7.2 8.4 9.2 12.1 5.7 11. 6 17.3 26F 6.8 7.2 7. 7 14 . 1 5.6 5. 8 12 . 3 18.1 Shortho r n 57E 6 . 5 6.6 7.2 10 . 5 8 . 4 11. 9 14.2 26.1 59E 6.6 6.0 6.6 10 . 3 9.7 .13.1 16.2 29.3 63E 7.5 6.9 7.4 10.6 6.4 15.8 13.7 29 . 5 Char ol ais Chill 6. 4 6.1 7.7 11 . 2 5 . 1 6. 2 17.3 23.5 Chl/2 5.8 5.1 5.4 14 . 9 4.1 6.8 18.8 25.6 73F 5.8 6.3 4.4 21. 2 11.0 4.4 16.1 20 . 5 Shorthorn- 71F 5.7 5.5 6.4 14.4 5.0 6.6 15 . 4 22 . 0 Charolais 67F 5.8 4.8 5.7 17 . 4 6.0 8.0 19.3 27,3 69F 6.6 6.7 5.7 23 . 0 7.7 6.7 14.2 20.9 '° Table 21. Individual data for number 2 rib roasts Cooking loss Panel scores Shear Press Animal Breed Method force fluid Drip Evap Total ntnnber Flavor Juiciness Tenderness lb ml % % % Hereford SE 1 6.8 6.7 7. 7 13.0 10.5 6.8 18. 3 25.1 llO E 1 6.9 6. 6 6.5 21.6 2 .1 9.5 18.9 28.4 12E 1 7 .4 7 .0 7 . 8 14. 6 2.0 9.0 20. 7 29.7 ll9 E 1 7.3 6 . 4 6.6 17.8 3.0 7.7 19.0 26 . 7 123E 1 7 . 0 6.2 7.6 14.0 5 .4 9. 9 19.9 29.8 SF 1 7 . 2 7.0 7 . 6 14.7 3 .9 3.9 23,7 27. 6 21F 1 6.6 6.8 7.3 14.2 2 .2 2.9 20.7 23 . 6 151E 2 5.8 5.6 5.1 18 . 6 4.6 8. 1 34.2 42 . 3 6E 2 5.8 6.0 3.8 19.2 10.6 10.0 26.1 36.1 136D 2 7.4 6.1 7.0 13.8 11.4 14.9 26.1 41.0 14C 2 7.3 6.5 7.2 16.6 2.0 15. 6 26 . 5 42.1 lF 2 6.3 5 . 9 6.3 18.5 7.3 5.5 30.8 36 . 3 16E 2 6.3 6.4 5.8 20.5 5 .6 13.6 25.9 39.5 161E 2 6.2 6.3 7.5 13.0 6.1 8 . 3 29.6 37 . 9 124E 2 7.0 7.4 6.6 19.3 7.3 9. 6 24.6 34.2 30F 2 6.9 6 . 6 7.0 11. 9 2 .1 14. 6 24 . 9 39.5 3E 3 5.8 5 .8 7.6 11.8 7.8 9.0 19.7 28 . 7 161D 3 6.6 6.6 6.7 15.3 6.8 10.3 16.3 26.6 18D 3 7.6 7.2 7.7 15.8 4.5 11. 0 13 . 2 24 . 2 155E 3 7 .0 7.3 8.1 )2 . 2 4.2 12. 6 19.4 32 . 0 ll2E 3 6.3 6.4 6.9 17.6 11.9 15 .0 16.5 31. 5 157E 3 6.8 6.5 7. 2 15.2 5 . 2 11. 3 20.0 31. 3 26F 3 7.7 7.0 7.7 12 .1 5 . 7 8 . 6 21. 8 30.4 >- 23F 3 6.9 7.3 6. 6 17.9 14 .5 4.6 18.5 23.1 0 0 Table 21. Continued Animal Panel scores Shear Press Cooking loss Breed Method number Flavor Juiciness Tenderness force fluid Drip Evap Total lb ml % % % Shorthorn 57E 1 6.8 6.6 6.8 14.9 7.8 8.4 20.0 28.4 59E 3 6.4 5.8 6.4 13.6 8.0 9.1 21. 3 30.4 63E 4 6.1 5.7 6.6 14.7 4.0 13.9 26.6 40. 5 Charolais Chill l 7.3 7.4 7.4 16.4 11. 6 3 .1 20. 3 26.4 Chl/2 4 6.3 6.0 5.1 24 .5 3.3 6.5 29.4 35.9 Shorthorn- 67F 1 6.4 5.7 6.4 15.7 5.8 3.5 22.2 Charolais 25.7 69F 2 6.4 6.1 5.6 19.7 3.0 7.1 30.6 37.7 71F 3 7 .0 6.9 7.0 16.0 10.8 4.5 21. 6 26.1 >-' 0 >-' 102 Appendix B Score Card for Beef Sample No. Flavo r Juicin ess Tenderness Comments Rate each characteristic from 1 (lowest) to 9 (highest). See descriptive adjectives for each characteristic posted in booth. 103 Adjectives Used for Scoring Beef Score Flavor* Juiciness Tenderness 9 Extremely full, rich Extremely Extremely characteristic juicy tender 8 Very full and rich Very juicy Very tender Full Moderately Moderately juicy tender 6 Moderately full Slightly Slightly juicy tend er 5 Slightly full Neither Neither 4 Slightly weak Slightly dry Slightly tough Weak Moderately Moderately dry tough Very weak Very dry Very tough 1 Lacking and/or Extremely dry Extremely masked tough *Any flavor which is not characteristic make a note in comrr.ent column on score sheet. 104 VITA Frances Glassett Taylor Candidate for th e Degree of Master of Science Thesis: Quality of Beef Roasts: Electronic Versus Conve ntional Cookin g Major Fi e ld: Food and Nutrition Biographical Information: Personal Data: Born at Salt Lake City, Utah, January 8, 1919, daughter of Martin C. and Marie Holter Glassett; married Sterling A. Taylor May 29, 1941 (deceased); two children- S. Elwynn and Marsha . Education: Attended Woodrow Wilson elementary school in Salt Lake City, Utah; grad uated from Granite High School in 1937; received the Bachelor of Science degree in Food and Nutrition from Utah State University in 1941; certified in Homemaking Education and Secondary Education in 1946; com pleted requirements for Master of Science de gree in 1969 at Utah State Universit y . Pr ofess i onal Expe r ie nce : 1967 and 1969, instru ctor , Depart ment of Food and Nutrition, Utah St a t e Univer sity ; 1966-67 , teac her, Loga n Junior High School, Logan, Utah; 1957-1959 , Labora t ory assis t ant, Department of Food and Nutrition, Utah State University; 1951 - 55 , assistant supervisor, Union Cafeter i a , Utah Sta te Un ive r sity ; 1944 - 45, teacher, Nursery School, Port Townse nd, Wash i ng ton. Af fili ations: Phi Upsilon Omicron, American Home Economi c s Association, Utah Home Economics Association, Institute of Food Technologists. Publications: Bennion, Marjorie, Marie K. Webster, Alison C. Thorne, and Frances G. Taylor. Kitchen arrangements. Utah Agricultural Experiment Station Bulletin 389. July 1956. Wilcox, Ethelwyn B., Leora S. Galloway, and Frances Taylor. Effect of protein, milk intake, and exercise on athletes. Journal of the American Dietetics Association 44: 95-99, 1964.