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Masters Theses 1911 - February 2014
1936 Preparation and preservation of apple pectin extracts Robert Vincent Murray University of Massachusetts Amherst
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MASSACHUSETTS STATE COLLEGE j
6/5 J Vi 'A 0
Robert V. Murray
Thesis submitted, for the degree of Vaster of Science
Massachusetts State College, A TABLE OF CONTENTS
"age
I. INTRODUCTION 1
II. REVIE* OF LITERATURE 2
A. Methods of Extraction 3
B. } ethods of Clarification 8
III. EXPERIMENTAL 11
A. Raw Material Survey 11
B. Determination of Optimum Extraction Methods for Raw Materials Used 12 1. Measurement of Jelly Strength and Yield of Extractions 14 2. Fresh Apple Extractions 17 a. Effect of Variations in Time 17 b. Effects of Variations of Temper- ature 18 c. Effects of Attued *cid 19 a. Effects of variations in Fruit to Water Ratios 21 3. Pomace Extractions 23 a. Effects of Variations in Time and Fruit to Water Ratio 23 b. Effect 6 of Added Acid, and Variations in Temperature 24
G. Clarification 25 1. General i'iscuesion 25 2. Clarification Methods 27 a. Filtration 27 b. Yeast Fermentation 27 c. Enzyme Treatment 29
D. Preservation 35 1. Required Thermal Treatment 35 2. Benzoate Preservation 36
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! t 37 E. Storage Life , 7 1. General Discussion J* Storage Life of Unclaimed Extracts 3a 2. 41 3. Storage Life of Clarified Extracts OF HOME IV. DISCUSSION OF THE POSSIBILITIES AND UTILISATION OF APPLE PECTIN PREPARATION 44 EXTRACTS 49 V. SUMMARY AND CONCLUSIONS 54 VI. BIBLIOGRAPHY I. INTRODUCTION
A suitable method for the preparation and preservation
of pectin extracts and concentrates from grade C or cull apples, end apple ponaoe, would provide a use for laatcriEla otherwise largely wasted. Apple pectin concentrates if
easily prepared would effect a saving for farm and orchard owners, farm factory and cider mill operators, end even for the housewife who might not wish or be able to pay the pre-
vailing high prices asked for the commercial pectin extr-.cts now on the market. There is a great abundence of litereture
pertaining to methods of extraction of pectinous juices, but the greet diversity of procedures reconraended and the lack of uniformity in the results obtained ore misleading and
confusing. On the other hand, very little work has been
done on the clarification, preservation end storage life of
pectinous extracts of fruits.
It is the purpose of this thesis to check the extraction methods now recommended and determine which is most satisfactory, to find a workable means of clarifying the extracted juices, and to discover insofar as possible, their storage life under various conditions. The work on methods of extraction of fresh epples will be largely a check on the previous work of Fellers (1928), pertaining to ratios of fruit to extraction water, tirae and temperature 2
of extraction, and the effect of the addition of organic
acids. The extraction of pomace front the sane apple
variations likewise will be employed. The olorif ioetion
of the pectinous juices will be attenpted by methods
believed to be in commercial practice, and storage life
will be determined by measuring the deterioration of
variously prepared pectin extracts stored under usual ware- house or farm conditions.
II. RjSVIEW OF LITiSRATURB
Pectin was discovered in 1825 by Braconnot, when he made artificial jellies with a peotln which he extracted
from carrots. Since that time many others have worked on
pectin, attempting to determine its chemical constitution,
its part in jelly making, and the optimum conditions for
its extraction from various raw materials, until today the
literature on the subject is very voluminous. For the pur- pose of this problem only the literature bearing on the extraction, clarification and preservation of peotin was
considered. Many have recommended a wide variety of
extraction methods but few hove considered tne problem of
clarification; all have considered the preservation of pectinous extracts to be a simple matter, but no one has ever determined their deterioration during storage. 3
A. Methods of Extract ion
Kany patents have been granted in various countries for methods of pectin extraction. Douglas (1915) received a British patent for extraction of apples or other fruits or vegetables by removing the natural sugars, e.g. expressing the juices of the fruit, and treating the pulp with a solvent such as hot water, which m>y contain acid.
Practically nil methods are variations or modif icetions of this one, but many ere more explicit. The Douglas patents were used exclusively by the Certo Corporation of
Rochester, New York, the largest manufacturers of liquid apple pectin in the United States. Hunt (1916) described a method of extracting pomace, cull apples, cores end peelings by three extractions of one part of raw material in three or four parts of boiling water; the pectin was
)gS0 obtained in solid form by precipitation with (NH4 2
(25 grs. per 1000 c.c. extract). Barker (1918) freed raw material containing pectin from acids by leaching with cold water or by neutralization. Pectous substances were then rendered soluble by treating the raw material with stoara, and were subsequently removed withhot or cold wnter; such a neutralized extract may be concentrated and preserved with sugar without jellying. In 1921 two
U.S. patents were granted, one to Barker (1918) for the 4
method described above, and one to Doell and kaes (1921)
for the extraction of pectin from fruit rind, peel or core by boiling in water containing citric or other acid find a bleaching agent such as cellite end boneblack.
In 1920 the Food Investigation Board of the Department
of Scientific and Industrial Research of Great Britain
reported that by the HCtion of heat and acid more pectin may be obtained from fruit tissue than is originally present
in the soluble state. This report stated that the greatest
amount of pectin obtainable from any raw material is that
extracted by the notion of hot dilute acid; steem pressure
extraction is less efficient than hot dilute acid, but is
better then non-acid hot water extraction. Beylik (1922)
received a U. S. patent for a method of preparation of
pectous material for jelly making; he treated the raw materiel with alcohol, ether, or chloroform to dissolve
substances other than pectous end cellular tissue, and then
dried the insoluble pulp. In the seme year lionti (1922)
received a patent for a method of extracting pectin with
water and concentrating in vacuo at a lo\* temperature
(40° C. or below) to preserve the natural fruit juice
Paine (1922) stated that the alcohol precipitate method for determining pectin content may not give con- 5
because cordant results when used on different fruits non-Jellying of the precipitation of other pectous but substances. Jelly quality may therefore vary with English different pectins. Leo (1921) was granted an of pectous patent for i method of producing a mixture treat- substances in row materiel conte ining pectose by from a non-acid ment with a solution of pectase derived received vegetable such as the csrrot. Crawford (1924) substances from raw a U. S. patent for removing pectous after sugars material by treatment with hot lactic acid Davidson (1925) re- had been removed with hot water. treatment of ported a method of pectin extraction by juices, with fruit pulp, after expression of natural solution. To remove a 0.07 - 0.15 per cent acetic acid fermenta- sugars the extract was subjected to alcoholic pectin was destroyed; tion, which was stopped before the concentrated until the the fermentation product was then when the acetic acid content reached 0.65 per cent,
product was bottled and sealed. ten hours Mehlitz (1926) stated that boiling for solution of 16 to 20 causes decomposition of apple pectin the first few hours. per cent, most of which occurs during for obtaining Bell and Wiegand (1925) gave directions of pectin - the " - largest possible extraction not over 212° F. with They parboiled fruit at temperatures 6
small amount of water for berries, th. addition of » very materiel the waight of the fruit for end of about one-half with- (apples, ate.) either with or high in oallular matter (1927) or tartaric aold. Nanji out the addition of citrio method involving the MM granted a U.S. patent for e peotin with dilute treatment of material containing ammonium tartrate, which er. solutions of salts, euch -a substantially all of the capable of rendering aoluble patent was greeted Sohwartauer, osctln oreaent. A British 11927) for a mean, of Bonigwerse and zaokerrsff ineri. substances, send and other removing soluble coloring stirring the rnw materiel in impurities by alternately pectin was water, end pressing; oold weekly noidulated acid extraction of the pulp. then removed by a hot to ' thet the optimum fruit Fellers (1928) determined and 3:3 sliced apples are used, TOter ratio is 3:2 where maximum yields used. He obtained where chopped apples ere extraction acid when he used two of juice, pectin end acid added v at.» 212on>° f.F Tertarlc periods of 15 minutes eaoh of - 0.4 in concentrations 0.2 to the extraction water yield, flavor, color htly increesed jelly p.r cent, sll E to the French patent was Issued end consistency. A removal of for e method of Pectineri. du ,ervor (19*7)
dilute lnorgenlc acid. with water oonteining 7
Myers and Beker (1929) determined that the jelly grade of pectins reached a maximum value when the pectin was extracted at a pH of approximately £.40; lower pH values resulted in a sh? rp decline in the Jelly grade of the extracted juice. They reported that jelly grade decreased with the time of boiling, although the yield of the extrrcted pectin increased with the boiling period.
The same workers (1931) found that as the extraction temperature increases the pectin yield also increases, but that in general, the higher the extraction tempera- ture the lower the jelly grade of the extracted juice.
Darling and MacMillan (1931) received a feft, patent for
the removal of pectin from apple pomace, after the extraction of palatable juices under pressure, by the addition of 10 per cent by weight of hot water and the application of much higher pressure. In the same yerr
a patent was Issued to the California Fruit Growers'
Exchange (1930) for the extraction of pectin from sub-
stances containing it, particularly cellulosic material,
by treatment with hydrochloric acid (pH 1.5 - 1.9) at
50° - 70° C. for a short period.
A German patent was Issued in 1928 to "Deutsches
Pektinges" (1928) for the removal of soluble substances
and calcium salts by treatment with water, not above B
S0 Pectin was then 40° C and containing a little 2 . Mithoff 11934) wee granted extracted with hot water. treatment of pectin, prior to a U.S. patent for butyl alcohol at about extraction, with dilute tertiary washing; this treatment 60 - 88° C. and subsequent materiel. Baker (1934) removes coloring and flavoring and alcohol soluble salts reported that tannins, sugars pomace by twice leaching, or may be removed from apple of 90 of the pomace in one part by soaking four parts activity is also and pressing. Snzyme Per cent alcohol Practically all mediately stopped by this treatment. method of are variations of the the methods described and with a suitable solvent, removing sugars and salts water, usually weakly extracting the pectin with hot
aoldlf led.
lcetion B. Methods of Clarlf
received en M*t* A* early a. MM Sougle. (MM) by of pectinone extract* patent for the clarlfIc.tlon or a atareh-converting treatment with malt extract wor* ha. that thne. hut little e„ zyme; however, elnce Caldwell phase of pectin production. been done on this pectin ex- of concentrating (1917) deeorlbed a method u.e of .operating the liquid by tract, by freezing and aocompll.hed by .training; he a cream .operator or 9
of celcium preservation by the Addition of one ounce the water carbonate to seven or eight gallons of reported a extractions. Megoon and Caldwell (1918) pectinous extrects means of removing matter suspended in of commercial alum, by precipitation, by the addition Crawford (1924) ammonia water, or heat treatment. proteolytic enzyme to treated pectinous extracts with a it is doubtful convert proteins to soluble substances; treatment. Perrier whether much was accomplished by this present in pectinous extracts (1924) proved that starch is from either dried fresh in largest amounts in those made drying treatment used apples or dried pomace, since the soluble. Juices from renders starch almost completely than juices from fresh apples contained less starch
fresh pomace. California Fruit A British patent granted to the various workers, among Growers' Exchange (1929) and Bender (1929), and Hipa them Bell and viegand (1925), obtained by centrifuging (1929), have reported results with or without pectinous extracts or by filtration highly porous material pressure, with the aid of some the last named in- such as "Celite" or "Filter-A id";
vestigator used ground nut shells. pectin extrects with Bender (1929), treated apple clear liquor from the solid casein, separated the 10
enzyme, then with sediment, treated it with diastatio it. Baker and activated carton and finally filtered diestatic action had a detri- Xneeland (1935) ^nted that grade of pectin nental effect on viscosity and Jelly was least at a pR value solutions, but that hydrolysis received a German patent for the of 3.*: PiBtor (1935) by treatment with clarification of pectin solutions the tannin combine, with tannin, followed by filtration; added in a proportion about the starch in solution and is
twice that of the starch. the large amount of This literature review reveals on pectin and on research that has been conducted great industrial activity extraction methods. There is patent, by the large number of in this field as witnessed satis- no one has proposed e issued. However, as yet scale preparation of apple factory method for the small
pectin. 8
11
III. 2XPIKI-2NTAL
A. Hew Materiel Survey *resh Apple
Baldwin Grade C culls, All the fresh apples used were two to six months. Once kept In cold storage for from temperatures, they were used removed from the cold storage as aulckly as possible.
Pome ce
from cold-pressed The pomace used was the residue dried to a moisture content King and Baldwin apple-cider, at stored in covered wooden boxes of 6 to 8 per cent and was accomplished by rod. tempemture. The drying immediately after its removal spreading the wet pomace, layers on screens which from the cider press, in thin equipped with three electric were then placed in a dryer moving fen. In this manner heating units and a rapidly F. passed a temperature of 1B0° a swift current of air at and drying was accomplished continuously over the pomace,
in 48 to 60 hours. the dried pomece In cold Two .xtreotlona of pert of <>t were then -a*,. M#» |M». ..tor. to renew, eueare. at to 96 pound, of weter ware wel! hroKen up. edd.d At th. eoe* for twenty nlnute.. 80o r. end allowed to off extraction water we. poured end of thl. «*. the 12
the type used in cider through a heavy corded cloth of possible was pressed from pressing, and bs much more as cider press. A second the pomace in a hand operated were then made on the similar extraction and pressing amount of water as in the same pomace, adding the same readings were made on first extraction. Saccharometer and on the two combined; the first and second extractions water containing altogether 165 pounds of extraction were pressed from the soaked 2.45 per cent soluble solids returned to the pomace. The pressed pomace was then at room temperature. dryer, dried as before, and stored
Extract ion Methods B Determination of Optimum /or Raw Materials Used
pressed cold from It is well known that Juices and therefore ennot fruits contain little or no pectin, reason for this is that be used in Jelly-making. The fruit and is not pectin is held in the cell-walls of broken down. This released until the cell-structure is may be accomplished disintegration of the cell -membranes reason, only heat most readily by heat. For this this study of the extracted Juices were considered in fresh apples were extraction problem. Both pomace and temperatures of successively extracted three times at
240° F. for from 15 to 30 minutes 190° F. , 212° F. and 13
strength and the total yields of juice, their Jelly soluble solids con- or sugar supporting capacity, their determined for tent end the total yield of Jelly was and second each extraction separately, for the first to- extractions combined and for all three extractions to gether, for fresh apples, the ratio of fruit pomace extraction water varied from 3:4 to 3:2; for The extractions the ratios varied from 1:6 to 1:16. of effect of the addition of different concentrations noted. tartaric acid to the extraction water was also Chlorinated tap water was used in all extractions.
fresh apples were first sliced in a hand slicing thickness, machine adjusted to give slices 1/4 inch in one inch in and pom ce was broken into flakes less than end diameter. The desired amounts of the raw material
extraction water were then put together in the con- temperature), tainers used (depending on the extraction as possible, the desired temperature obtained as quickly temperature for and the heet regulated to maintein this for extractions the duration of the extraction period, slumlnum pans et the boiling point or below, 10 quart convenient; equipped with close fitting covers were found from ordinary gas in the former case heat was obtained temperature con- stove burners and in the latter from a 14
at 240 ¥. steam trolled water bath. For extraction the extrection pressure cookers were employed. V/hon pulp were poured period was completed, the juice end drain for a minute or into a cheesecloth, allowed to twisting the ends two and thoroughly squeezed out by minutes. The of the cloth in the hands for several desired quantity of pulp was returned to the pan, the made; in like water added, and the second extraction Examination of manner a third extract was obtained. the extracts was made ^mediately.
Strength and Yield of Extractions 1. Measurement of Jelly
use the Present qxiantitetive methods in general determining the pectin alcohol precipitation method for precipitates content of extracts. In all alcoholic of pectinous compounds there are present certain amounts At the present time that do not possess jelling power. Jellifying pectin we have no method which differentiates procedure is greatly and non-jellifying pectin. Such a analysis was made by needed. In these experiments no Instead, a chemical methods for pectin determination. was employed to method evolved by Myers and Dakor (1927) pectinous juices. The find the jelly strength of the is defined as being jelly strength of a pectinous extract 15
end is expressed in th« its sugar supporting capacity weight of juice to units of sugrr jelled by one unit strength. These investigators give a jelly of definite pectinous juice is a found that jelly strength of • relationship being in- function of its viscosity, this tae pectin. Since the dependent of the concentration of the amount of added yield of jelly is dependent upon sugar is dependent on the sugar and the amount of added solution, the relative relative viscosity of the pectin the jelly yield. viscosity of the solution determines genersl empirical formula for Baker (1934) has evolved a velue of a pectin ex- converting the relative viscosity strength: tract into terms of its jelly .195 lg y m .833 x viscosity where y - the relative of sugar jelled ana x . the unit weights by one unit weight of Juice
x - 195 In terras of x : lft y ^£
of the extracted juices, for measuring the viscosity devised by baker (MM) a simple "jellmeter" originally inches of capillary was used. It consists of several to a small glass tubing (.02 to .04 inches) sealed the time required for cylinder of several cc cecity; etched mark on the glass the juice to flow from one 16
time required cyllnaer to another below divided by the gives the relative for water at the same temperature the viscosity of the juice. In these determinations and the flow at jellaeter was held vertically in a clamp From the data so 76° r. was timed with a stop watch. extracted juice, the gathered the jelly strength of the and the theoretical yield of jelly per unit of juice, the extractions, total yield of jelly obtained from by Beker' formula. separate and combined, was computed I par unit of juice and The computation of jelly yield basis of a finished total jelly yield was made on the per cent, which Fellers jelly with a sugar content of 67 Borne of the extracted (1928) found most satisfactory. according to Baker's juices were used to make jellies constant in giving jellmeter ana formula, and were so experiment the satisfactory results that later in the and yields and jelly practice was largely discontinued, Readings of soluble strength values merely figured. were made on an Abbe solids content (lorgely sugar) refractometer at room temperature. 17
2. Fresh Apple Extractions
a. Effect of Variations in Time
In Figure I and Table I are shown the results of successive extractions of 15 and 30 minutes each at 312° F. using 3 pounus of sliced Baldwins and 3 pounds of water.
It is seen that in the 15 minute period each of the three extractions produced a juice successively lower in jelly
strength, jelly yield per unit of juice ana soluble solids content, that the strength of the first two com- bined was slightly lower than that of the first, and
that the three together were much lower that the first and second extractions combined. However, jelly yield
is not dependent only on the jelly strength of an extracted
juice, but also on the total yield of juice. Considering
the relative value of the extractions on this basis, the
first and second extractions together produced a large
yield of juice of a fairly high jelly strength, which re-
sulted in the greatest total jelly yield, and entirely overbalanced the apparent advantage which the first extract
alone would possess if only jelly strength were considered.
Although the addition of the third extracted juice sub- stantially increased the total juice yield, it so weakened
its sugar supporting capacity that the result was to decrease the total jelly yield. The first 30 minute
of Apples and 3 Pounds Table I. Extractions of 3 Pounds *R ter for 15 minutes et 212° F.
Y^eld ?arts of Totfcl Jelly per Jelly 15 Minute Relative of Jelly Viscosity Juice strength* One Pert Yield Extraction Juice ounces ounces .5933 33.09 First 3.36 55.75 .3977 .3880 19.92 Second 2.58 51.35 .2600 end second First .5258 56.58 combined 3.08 107.61 .3523 .1540 5.58 Third 1.91 36.25 .1032 .5560 47.49 Three coublned 2.42 140.42 .2266
30 Minute Extra et ion .4807 .7174 37.30 First 3.94 52.00 .2746 9.52 Second 2.23 54.66 .1840
end second First .4816 41.70 combined £.91 86.60 .3227
by weight of sugar * Jolly strength is expressed as parts jelled by one unit weight of Juice. 18
exceeded the first 15 minute extraction at 312° F. greatly jelly strength and yield, extraction in relative viscosity, but the second was almost as and soluble solids content, the third of the successive poor in the same respects as Together or singly, they 15 minute extraction periods. two 15 minute extract, did not equal the combined first
in strength and yield.
of Temperature b. Effects of Variations
the extraction tem- Myers and Baker (1931) state -As pectin increases when the perature increases the yield of It is therefore extraction period remains constant. yield at any definite impossible to obtain as great a under optimum conditions temperature as may be obtained, As the temperature of the at a higher temperature. grade of the extraction .eriod increases, the Jelly the extraction oeriod resulting pectin decreases when obtained in this experiment remains constant.- The results statement of these investigators. are In agreement with the the results of two Table II and Figure II picture of apples with 3 pound, euocessive extractions of 3 pounds pounds of steam pressure of water for 15 minutes at 10 compared with the two 15 (340° F.) and at 190° F. , as fruit to water ratio and minute extractions using the same
a temperature of 212° F. CD O S3 S3 eq O -H r-i O ,0 C\J CD g P -w e- CO • o o o Cm w o o k\\\\\W CO co CO p ©o o -P o V////////IIIIIIIITTTri p CC 2 o» CO S3 H p to a u0 0 •H P o o Sh •H CO P p X O fH M ct) O p S3 o 3 o 0) o to S ft," o o p S3 C\J o o CO CO S3 p M CO X CO p § CO V///////////////////WW/ u •H uCD •H CO • aoin f jo ^iiSt4» ^fun 9uo jibSiis jo qinSiaM Aq s 1 CO o» to C*> C*» E> 0» H tO tOHO» OOiH • • • • • • • • • JO r-( r-i tO IN 0> CO r-t t- OS O W (O S* i-l O © -H 3 CO «# r-t r-t to © H ^9 >* o r-t P© c o u © p O a. u ro to tO 03 O CO t> « O to •O HlO CO «*• 5 co o tO CD O Cft O* ^* CD CO W P r-t tO <# CM O tO tO r-t OHM r-t © — O f-t P h •<# O £S © © S3 o -5 p • © *A *SO >» P to tO t> o r> O W t> cw* e> <© W W t> >» t> to o o C O P BJ o V. H OS «r .C © © p r-t p p tO to o» CO O O CO OD o o» o •H 00 tO CO • • • o s S « • • • • • P o CO w w CO CO r-t WWW r-frj O 03 O © P r-t © © «H P©OP(h « a o a oh © t-. p © » 1 P o © a WOO woo woo C p fttJ P © r-4 CB rH O ft r-t <3» O ! tn 3 a i oa tH W W r-t W W H p c "H fl © © w M -H © ft a so © © © O r-t •H © P •a s a C c p ' © p OR .O w o hOt, (-1 o r-t O P *-t « S K St, 9*< CO f« O 19 to be the least The temperature of 190° F. proved tried. The efficient of all extraction temperatures first and second soluble solids content of the combined that of the two, 15 extracts e*» only 54.1 per cent of jelly strength was minute, 212° F. extractions, and the the yield of juice was but 38 oer cent as high. Since yield was only approximately the same, the total jelly 35 per cent as great. strength ana soluble in res.ect to juice yield, jelly minute extracts at solids content, the first of the 15 taken at the 15 minute 2400 F. surpassed any of those however, produced a lower at 313° F. period; the second, capacity, that the two yield so weak in sugar supporting as much jelly as combined coulu produce but 83 per cent at 213° F. the first two 15 minute extracts c. Effects of Added Acid extraction water Tartaric acid was aaded to the first per cent of the combined in quantities equal to 0.2 or 0.4 and the same amounts weight of apples and extraction water, second extraction. added again to the water used in the at 213° W* using a The period employed was 15 minutes weight. Of all methods fruit to water ratio of 3 to 3 by can be judged by attempted, this was most efficient, as those obtained in the the comparison of the results with 20 acid. Figure III and same extraction without the aaded apparent between the Table III. Ho great difference was juices extracted with yield and strength of the combined which 0.4 per cent was used; 0.8 per cent acid and those in the 0.2 per cent extraction. a slight advantage lay with extractions occurred The greatest gain over the non-acid first 0.2 per cent in the first extracted juice; the first 0.4 per cent extract was 27.4 per cent, and the jelly strength than extract was 18.7 per cent higher in second 0.2 per cent extract the first non-acid juice. The 0.4 per cent extract was slightly weaker, and the second than the correspond- was approximately 30 per cent stronger jelly production of the ing non-acid extract. The total juices was 15 per cent combined 0.2 per cent acid extracted juices; the jelly yield greater than that of the non-acid was slightly less of the 0.4 per cent acid extractions A deeper than that of the 0.2 per cent extractions. pronounced apple flavor readish "apple* color and a more were distinctly noticeable than in the non-acid extractions the jellies made from in the acid extracted juices and in them. a o • H ra to end 1 acid •H Xi cts . +3 vt t i 4 CO O CO CO P -P c •a +j 1 li ad o (D CO , ///////////////////// M 1 O O N ex. an < X) xs XS -a •H tH •H M fn © fi ill ni Tartar! 3:4, CO CO d! ft ft 1 I I Secoi a d c-! evi ^« Combii o o o iT,es ad it coo a ce tun 3:3, 3:2, 3:4, 3:3, 3:3, 3:2 per -p id o (0 m to ^ 3 •* • p H tO O iimiiui, X E poora u xs O CO cO ra MOW Second p 'H . \\\\ X -P o ^ CO « t»D 0 ^ c -i © A M <0 CO O H= -P -p Pi o O o O -P O a) //'////////// f- 3:3 Ext Fruit uompari First i. - 1 - i =f t H 0) So • H 1 o CO to w o r-i I pnf jo m2i:©m ^jun auo j£q pexisf ja3ns jo - (0 0 I h ® U V« © p rH P CO 0 em m 00 O O CO CO H rH rH X CO O CD CO O OJ to to 0 © M U 03 >»"-. © O* H 02 CO 'O to CM tO tO o PH O tO CO tN to to to lO CS O U rH O • • • • • • • • •H O S3 © fl 3 © O 1-i S3 > «H tO CD O CO r-J SO co w to O •H « tO C» to tO CV] 0 0 tO © P O • • • • • • • • • © C • ai 0 to to CM CM tO to ^ to © 0 ^ H as © i © «r| rt •HO Q5 t» P. • u cm X © 1 rH © 0 P.W .iater Ratios d. Effects of Variations in Fruit to varied The 3:5, fruit to extraction water ratio, was at 212° F. for to 3:2 and 3:4, and extractions were made failure, for although 15 minutes. The 3:4 extraction was a strength was low, and the juice yield was high, its jelly of the yield the total jelly yield was but 66 per cent and time. The from the 3:3 ratio at the same temperature the sugar supporting 3:2 ratio was much more satisfactory; very high, but the values of the extracts were relatively jelly yield was juice yields were low, so that the total extraction. actually 10 per cent less than in the 3:3 and Figure III. The results are pictured in Table IV the extraction The ultimate test of any method for is the total amount of of a pectinous juice, however, the extracted juice will jelly of a definite grade which grams of the extracted produce, in this experiment 100 amount of sugar, depend- juices were added to the required of the juice and computed ent upon the relative viscosity The solution was put in a small by Baker* s (1934) formula. sugar concentration aluminum pan and boiled until the was then immediately reached 67 per cent. The jelly allowed to stand for poured into two-ounce glasses, and instances the resulting 34 hours, in all but one or two 0» CO m o o» CD tO O C- CO o> o o in h o O * • • • • * • • • to 43 © O SO 03 CD tO tO H to OJ CO 00 tO N in o t> -o to © cr> cj eu CO ft! O « "-"3 \d « tO tO H u a to 3 a o Ot-"* tO MflOo to t> OOrl <-» moo £ >> x> Q in 01 r-i in P to N t> C> to sa m o m • • • u • • • • • • t> t> rH © cc rlOO o o tO to p. m so in in to to O 60 «s © tO rH to to o t> mooco t> ^# OCJMCO woo • • • © • « * • • • OJ 5-. noso OJ to i-J CO M © © o a 3 P O CO OJ to OJ •H «H © eo to © CO to to tO tO tO CO £ ra © r-t +3 © c p P *-3 3 o o o -p at £5 © a M O h e o lH P f«4 &4 S3 CO w © W 22 that retained it. jelly was of a fairly firm consistency glaee. If the 100 gram shape on being removed from the total jelly which portion formed a goou jelly, tnen the batch of extract was could be obtained from the whole sugar which would calculated by figuring the amount of cent sugar in the be required to give a content of 67 x>er jelly made from the extract. yields of jelly obtained In Figure IV are pictured the of apples under the from the extracts of three pounds already described. In only various extraction conditions extraction for 15 minutes one instance, that of the 3:3 two extracts the jelly yield from the first at 2120 F. , was or second singly. combined less than either the first were obtained from the combined The three best jelly yields 313° F. extractions. The first and second 3:3, 15 minute, which 0.2 per cent tartaric best of those wa. the extract to containing 0.4 per cent acid was adued, the next the one non-acid extraction. Extract- tartaric acid, and third the gave the poorest results, ion at a temperature of 190° F. 312° F. the 240 F. and the 30 minute extraction at , fruit to water ratios were extraction, and the 3:4 and 3:3 yielded but little jelly- intermediate. Third extractions lower the total jelly yields. ing pectin and only served to to TJ -P 0) o a a> (0 -h Ih4J g •H ^ « O O Eh N rj> ~c3~ W a * T3 o o ?H •H •H p X! o P-H EH o pg i CV2 CM CO (0 • p (0 o •h W4- Fh S •H /i '//,'/////// H 33 3. Pomace Sxtractions optimum methods for In attempting to determine the apple pomace, obtaining pectinoue extracts from dried temperature as used in the same variations of time and employed, and the effects the fresh apple extractions were but the ratios of of aaued tartaric aoid were noted, 1:6 to 1:16 by pomace to extraction water varied from proportion of extraction weight. The reason for this large the pomace, being dried water to the raw Material is that than per cent, absorbs to a moisture content of less 8 greatly decreasing much waier during the first extraction, of scorching. In the the yield ana enhancing the danger pomace was added to 3 1:6 extractions one-half pound of one-third of a pounds of water; in the 1:12 extractions pounds of water, and in pound of pomace was used with 4 pound of pomace was ex- the 1:16 extraction one-quarter tracted in 4 pounds of water. in Time and Fruit to Water Hatio a. Effects of Variations apple extractions, no in the pomace, as in the fresh temperature proved of any third extraction at any time or jelly grade of the value, but served only to lower the jelly yield. In juice and greatly reduce the total strength values of the summarising the results, the jelly 34 different extracts proved of little oomvmrative worth, due to the large differences in Juice yields obtained by the various methods attempted. Thus, the Jelly strength of the combined first and second Juices extracted from a pomace to water ratio of 1:12 at 212® F. for 15 minutes was but 38.8 per cent as high as that of the two oorabined Juices extracted under the same conditions from a 1:6 pomace to water ratio (Figure V). But since the yield of Juice in the former case was 2.6 times a! great as in the latter (Table V) the ultimate total yield of Jelly was slightly greater (Table V and Figure VI). The true criterion for the value of an extraction method, especially in pomace extractions, is therefore, the total Jelly yield obtained. Total Jelly yields obtained under varying conditions are compared in Figure VI. Temperature b. Effects of Added Aoid and Variations in The combined first and second extracts in all cases yielded the largest amounts of Jelly. Of the different efficient, pomace to water ratio's attempted, the 1:13 was most The the 1:16 least efficient, and the 1:6 intermediate. of 30 minute period in all cases produced, a lower yield 15 Juice of a poorer Jelly grade than the corresponding minute period. The extraction made at 190° F. was a total pto o CO PfH -a £0 CO X CD CQ vi/ 1} c •H CD p CD S3 c a fH C"* •rH o •H a a o H 0 o o 8 o CO to CO p CD CM P CV3 «l CjOrH i-l V////////////////////// ///A S3 C\J 0) •> S3 u p tb O +3 03 \\\\\\\\\\\^ O CD CO CO >> CD rH P CD S3 o o to o -a to c •H 00 fH W//////////////77777. P,rH p to 6 fH o •H P>H CD fH g> &H CT -oo- ~C\T q.xun eujo psuef js3ns joi q.q9j8M. iCq ca rH i»»tJ © O CD ts tO iO CO CM i-t rH rH CD H lO W fflHH CC SO CM tS tS O © "I CM p > * p CM CM BO 0> C» CM (£> 10 CM cs o CO o> so co iO to o tO CO Ok tO CO H O tO CM t> o CO O tO CM CO H 2 WHO o CO ^ O to © p • • • « • • • • • • • to CD T=J © MO OO O O lO tO tO tO CM m O H O CO IS r-i CM co o e- o t> ^ C0 H © fl • • • • • • • • • • • * o co <# o» H CM to CO CO tO o CO o CO N CO to CO O to CO to *> 43 H 50 © OJ O ID tO CM CO O CM to o o to O *0 CM CM lO C -M lO H to o o • • • • • • • • • • • • H H M •3< in co to H CM H CM CM CO CM CO IB co oS 09 -P > «H H © tO CO CJ (J) to o +3 C 00 o- to to o to o co co to • • • • • * • oS o * • • • • H CO CM CO H SO CM CM H t> CM CO H • si 0 i •H «> to P c © CM O O CM CM O O CM CM O O CM o N © r-i*t> & r~i r-i -4* Ot H H CO H CM CM CM CM CM CM CM t > CO h CM CM H H H U P« « I © X © &3 H i P < P © P © -<3 -O <© © o •H ft «rt u o *© © "O © O O © «d *© H -H «rt h © © © p. o o o © 1 1 1 o o o • © © a. CSC'* p co e> I I i o o o a P t^* i i I O C C f o o CJ C o o o • «0 >o "O •© O O O I *M o O © © © © o XS "Q "O "O Xt o a a © e a c •H «H «H 1-t «H CO K CO CO o o o o o >3 JO O p fi u u u o o o x> failure, and the 312° F. 0.4 per cent aoia extraction produced juices giving the largest yield. One difference noted between fresh apple and pomace extractions was that the pomace at 240° F. yielded more juice of a higher nectin grade than under otherwise similar conditions at 2120 F. , whereas fresh apples at 240° F. yielded less juice of a lower grade than corresponding extractions at 212° F. A standing period of 10 minutes during which the pomace soaked in the extraction water at about 50° F. before the extraction temperature was attained proved of no Vflue whatever, the juice yields, soluble solids content and jelly grade being exactly the same as in the correspond- ing extraction without the standing period. The only difference between extractions of pressed and unpressed pomace was in the soluble solids content, the pressed pomace containing on an average 75 per cent less than the un- pressed poiaaee. 0. Clarification 1. General Discussion Fectinous juices extracted by heat from apple pomace, and more particularly from fresh apples, contain in colloidal suspension a large amount of very finely divided material, besiues the nectin, which is not removed when 26 the juices are strained through cheesecloth or through & felt or flannel filter. This suspended material, mostly starch and oroteins, causes a heavy turbidity or oloudi- ness in the extract which becomes more ronounced when the extract is concentrated. Such a cloudy juice is unattractive and cannot be used in jellies without one causing a scummy surface and loss of clarity. After or two months storage of the extracts, especially at down room temperatures, the suspended material settles gelatinous and becomes a muddy, thick, and sometimes even sediment on the bottom of the container. In this ex- periment great difficulty was experienced in measuring and the the viscosity of the concentrated extracts, irregular. results obtained in these measurements were often which an extract It was observed in certain instances in Juices showed a viscosity much above the average for that extracted and concentrated under similar conditions, alone, but also the viscosity might not be due to oectin This observation partly to the suspended starchy materials. the matter, for may have been the correct explanation of concentrated juices when jellies were made of some of these found that their of unreasonably high viscosity, it was indications of relative viscosity values were not true of sugar their jelly strength, ana that the amounts 27 necessary to add according to Bf.ker 1 s (1934) formula were not jellied, being in all cases excessive. For these reasons attempts isere made by various methods to clarify the pectin extracts. 2. Clarification Methods a. Filtration Filtration through cheesecloth and through felt and flannel bags being unsuccessful, an attempt was made at clarification by passing the extract into a filter flask through "Filter-Oel" held in a Buchner funnel by a circular piece of canton flannel covering the funnel bottom. Suction was provided by an aspirator attached heavy to a sink faucet and connected to the flask with a rubber hose. By this method, some of the turbidity was removed, but the juices still remained clouay, and a them more or less heavy layer of sediment settled from after about two weeks storage. b. Yeast Fermentation Half-liter amounts of unconcentrated fresh apple content extract of known viscosity and soluble solids liter were placed in Erlenmeyer flasks of about one different capacity, inoculated with pure cultures of four 28 strains of yeast, the top* of the flasks plugged with cotton, and the whole incubated at room temperature for from 5 to 7 days, or until fermentation had ceased. The fermented extracts were then filtered through »Filter-Cel" and in a Buchner funnel, and tested again for viscosity soluble solids content. The Juices treated with yeast in this manner possessed sparkle a dull, translucent sort of clarity, but lacked thin and brilliance, and after several weeks storage a relative layer of seaiment settled from them. The average viscosity value before the yeast fermentation, 3.53, had This fallen to 3.23 when the fermentation had ceased. difference is equivalent to a loss in Jelly strength of seems to the extract of .0466, a negligible amount which The soluble indicate that yeast does not destroy pectin. solids content fell from an average of 5 per cent to saccharimeter. 0 per cent as determined with a Brix Clarification by yeast fermentation was entirely cultures unsatisfactory. In eight attempts, using pure single extract of four different strains of yeasts, not a filtration alone. was clarified more successfully than by 29 c. Enzyme Treatment Since the cause of the cloudiness was believed to be largely colloidal starch, it was decided to attempt the conversion of the starch into more soluble sugars by enzyme action. Starch is converted by the enzyme diastase into maltose. For this purpose Medicinal diastase of malt, U.S. P. was purchased, and two preparations intended expressly for purposes of fruit juice clarification in commercial practice were furnished by their manufacturers, "Protozyme Px" by Jacques Wolf & Go. , and "Clarex" by the Tekaiaine Laboratory, Inc. Specifications for the use of Protozyme Px were followed closely, and its action compared with that of the other two preparations under the sauie conditions. Later, variations were introduced into the methods by using all three. According to Baylies (1935) and \;aldschmidt (1929), the end products of enzyme uction do not depend upon the concentration of the enzyme present. However, the rate of the reaction does depend partly on the concentration and also on the temperature at which the reaction takes place. The greater the concentration of the enzyme, and the higher the temperature at which the conversion occurs, up to a certain degree, the quicker the reaction. Tem- peratures above 60° C. readily destroy diastase. The 30 producers of Protozyme Fx recommended as the optimum conditions for the use of their preparation a concentration of 0.1 per cent on a weight basis, and a temperature of 120° F. They state that conversion will occur at this temperature in 40 to 75 minutes, depending on the amount of starch present in the solution, or at a temperature as low as 74° F. , the reaction being slower at the lower temperatures. If the juice is to be filtered after treatment, it is not necessary to extract the enzyme from the substrate carrying the enzyme usually bran or a similar substance. However, it will go into solution more quickly if it is first leached for 15 to 30 minutes in about four times its weight of the juice. This oroceedure was followed in all treatments in this ex ieri- ment. The enzyme was destroyed at the end of each conversion period by heating quickly above 160° F. The end point of the reaction should be indicated by the 'characteristic reddish-brown color" appearing when the sample is treated with a dilute iodine solution. This oolor reaction was indistinguishable in the treat- ment of the apple pectin extracts, however, perhaps because of their natural reddish-brown color. Extracts of fresh apples, pomace and pressed pomace were treated (both unconcentrated and after concentration 31 with all three enzyme to 1/5 of their original weight) minutes, preparations for periods varying from 35 to 110 90° F. The extract to and at temperatures of 120° F and aluminum pan and raised to be treated was poured into an it in a temperature- the desired temperature by immersing enzyme was then controlled water bath. The leached same temperature for added and the whole held at the period, at the end of the duration of the conversion temperature and twice which it was heated to boiling Buchner funnel. filtered through Filter-Cel in a measurements were taken at Soluble solids and viscosity treatment, and immediately after 76o F. before the enzyme the final filtration. clarification of pectin- The results obtained in the medicinal Diastase Merck, ous extracts by treatment with "Protozyme Px,« and with with the Jacques Wolf product were equally very satis- the famine product «Glarex,» apple was observed that fresh factory, in general, it for conversion than extracts required a longer time clarification is more complete ,omace extracts, and that on the unconcentrated and more easily accomplished after concentration. extracts than on the extracts extracts which were treated Thus, unconcentrated pomace brilliant 12QOF. filtered to a clear, for 50 minutes at the formed on the bottom of liquid, and no sediment had , 32 container after three weeks storage at room temperature. original Extracts which were concentrated to 1/5 of their enzya*» weight and then treated for 50 minutes with extract before equal to 0.1 p»Z cent of the weight of the slight concentration were slightly cloudy, and showed a of 75 sediment after three weeks storage. A period to accomplish minutes at the same temperature was required period for the as complete conversion as the 50 minute fresh apple unconcentrated extraot. For unconcent rated less than 70 extracts, any period of enzyme treatment fresh apple minutes at 120° F. and for concentrated at 120° F. failed extracts any period less than 90 minutes from which no sediment to give a perfectly clear juice Another factor in settled during three weeks storage. concentration is the favor of enzyme treatment before pectin extract as difficulty of filtering a concentrated slowly, almost drop such a viscous liquid filters very high vacuum be drawn on by drop when cold, even though a flows faster, but boiling the filter flask. When hot it resultant loss of liquid or foaming up in the flask and filtration continues and the is very lively to occur as vacuum in the flask increases. impossible or impractical Under conditions where it is temperature of 120° F. to maintain an exactly regulated accomplished at conversion may be just as satisfactorily 33 temperatures of from 80° F. to 90° F. by allowing a longer time for the completion of the reaction. The enzyme treatment at 90° F. and subeeouent filtration resulted in a well clarified juice when a 90 minute period was allowed for the reaction in unconcentrated pomace extracts, and when a 110 minute period wae In allowed for unconcentrated fresh apple extracts. 120° F. and some oases in which the reactions, both at continue for shorter periods at 90° F. , were allowed to of the complete conversion, as judged by the clarity others, clarification filtered juice, ws s accomplished; in turbidity and sediment was imperfect, varying degrees of constituted remaining. The periods noted in Table VII for the different the shortest reaction times allowed temperatures, in which there were no failures. to clarify Difficulty was encountered in attempts extracted juices. extracts of pressed pomace, and acid pomace extracts The clarified unconcentrated tressed had been concen- were fairly clear, but when the same developed within several trated after clarification they discoloration. It was days an opaque greenish-black imperfect filtration, believed that this might be due to retained the dis- but after refiltering the extract extracted juices coloration. The unconcentrated acid as the juices extracted were not as completely clarified of VII. Time Required for Enzyme Clarification Teble and 90° F Pectin Extracts Treated at 120° 7 . at Extraction Tine at Tine 120 F. 80 F. minutes minutes Concentrated Pomace 75 90 Uneoncentrated Pomace 50 Concentrated Fresh Apple 90 110 Uneoncentrated ifresh Apple 70 34 without acid, but remained rather cloudy. This cloudiness was moie pronounced when the extracts were concentrated after clarification. Within 34 hours after concentration of heavy, and bottling, approximately a quarter of an inch a the white, partly crystalline sediment had settled to the bottom of the half-pint ^ars used as containers, and extractions supernatant liquid remained cloudy. Ho acid found were successfully clarified. Ho explanation was for either of these difficulties. Viscosity measurements were made on all extracts filtration, before enzyme treatment and after the final the action and in no case was the viscosity lowered by The average gain of any of the three preparations used. enzyme treatment was in soluble solids content during and 1.1 0.75 per cent in the unconcentrated extracts, Some of the per cent in the concentrated extracts. while clarified extracts were stored unconcentrated, All retained others were first concentrated 1 to 5. concentration. The their brilliance and olarity after temperatures of the results of the various times and extracts are conversion periods used on the different given in Table VI II. +2 o g P >» p c © •* H O P 3 3 o a >> © G a 3 3 *h o rl E > o rH 8J «H © © rH © o *3 SI O © © © a VI ' 1 *y © 3 13 rH © rH © p O CO © p O © >>P O © p O +3 © p rH S3 rH © rH 3 p p o © o P © t»»P i>> © >> © O © -a £2 ,3 >» rH i J >» > IS-tH U <*J 3 "H (H •H »H © «H 3 M at 3 3 © C © P P P rH © © © M © P P P p Eh c; 3 3 3 CO « © © N o o O P p c 3 P c H o o O 5 2 K O o to 6 35 D. Preservation which the In order to determine the deterioration each extract Deetinous juices might suffer during storage, by thermal was bottled in half-pint Jars and preserved Pre- treatment or by the addition of souium benzoate. those which servation of the extracts, particularly of be simple had been concentrated, *as discovered to a acidity, the matter. This was probably due to their slightly above unconoentrated Juices having an average 0 pK between 3.5 and 4.0. 4.0, and the concentrated juices a %, p.equired Thermal Treatment which remained Of the unclarified extracts, those half-pint jars unconoentrated were filled into clean which were immediately after extraction, and those concentration, concentrated 1 to 5 immediately after immediately processed either in all cases the jars were pasteurised at 170 F. for at 312° F. for 10 minutes or controlled water bath, or 10 minutes in a temperature further application of sealed and stored without the were heated to approximately heat. The clarified extracts filtration, filled into the jars 200O F . after the final same treatments as immediately and then given one of the the unclarified juices. 36 or In none of the juices which were pasteurized preserved was there any sign of fermentation or iaola 40° or at growth jifter four months storage either at fi which were room temperature. The concentrated extracts kept filled hot and sealed without heat treatment all of without spoilage, but among the 'twenty-three jars eleven unconcentrated extract preserved in the same way, first three weeks showed £ surface mold growth within the between the storage. There was no apparent difference and that of keeping quality of fresh apple extracts and unclarified pomace extracts, or between clarified extracts. 3, Benzoate I reservation benzoate in The maximum concentration of sodium cent by weight. In foods allowable by law is 0.1 per the pectin extracts by the attempts at preservation of of .05 per cent and the use of benzoate, concentrations benzoate was added to the warm .1 per oent were used. The thoroughly stirred concentrated and unconcentrated juices, juices immediately bottled, into complete solution, and the temperature both con- aithin ten days storage at room containing .05 per centrated and unconcentrated extracts of mold growth on their cent benzoate had a thin pellicle , 37 surfaces. The viscosity of these extracts had not been reduced, k sodium benzoate content of 0.1 per cent did prevent mold growth in the concentrated extracts, and the in about half of the unconcent rated extracts for three seeks during which the juices were in storage. values However, after the first ten days, the viscosity unconcentrated of all these extracts, both concentrated and seriously had been reduced by approximately one-half, preservation impairing their jelly strength. In genersl, unsatisfactory by the addition of sodium benzoate was and is not recommended. E. Storage Life 1. General Discussion literature There is no material in the voluminous of storage under on pectin which pertains to the effects It has been the various conditions on jellying pectin. attempted the experience of some, however, who have as a jelly preservation of pectinous extracts, either that the pectin under- stock or as a pectin concentrate, of storage a goes auring longer or shorter periods it loses jelly deterioration in quality; that is, that its sugar supporting strength, or in other words, that 3a capacity is decreased. It was therefore undertaken as a part of the problem of pectin extraction and pre- servation, to determine as far as possible the extent of this deterioration, and to discover under which storage conditions it le least serious. In this experiment pectinous juices of known viscosity were stored, clarified and unclarified, concentrated and unconoent rated, at a temperature of 40° F. and at room, temperature, 76° F. At the end of one, two and strength, three /nonths storage they were examined for jelly using Baker* s (1934) jellmeter and formula. The viscosity measurements of the unclarified concentrated extracts were in several instances obviously inaccurate the and not truly indicative of the jell strength of after extract; in these cases the viscosity was greater extract was one or two months storage than when the extracts, first made. When jellies were made of these jell sugar was added according to their indicated always ex- strength, and w&s in no case jelled, being discussion on cessive. As already explained in the these inaccuracies the clarification of pectinous extracts, starchy were probably due to a coagulation of the filtration substances which were not removed by extract which immediately after extraction, fehen an storage was filtered showed » gain in viscosity during 39 through Filter-Gel in a Buchner funnel, and again measured in the jellmeter, its viscosity measurement was close to the average determined for other juices extracted and stored under similar conditions. When the filtered extract was made into jelly, the viscosity measurement was found to be the true indication of the jell strength of the juice, for in all cases the amount of sugar required by Baker's (1934) formula was jelled, So similar difficulty was experienced in viscosity measurements on clarified extracts. 2. Storage Life of Unclarified Extracts During two months storage of the unclarified the extracts, loss of jelly strength was greatest in unconcentrated pomace extract; in all cases the extracts than those stored at 40° F. lost less jelly strength jell kept at room temperature. Thus, the average extracts strength value of the unconcentrated pomace cent after two kept at 76° F. showed a loss of 64 per F. lost months, while the same extracts kept at 40° original strength an average of 37 per cent of their pomace extracts during the same period. The concentrated original during two months lost 4 per cent of their per cent at 40° F. strength at 76° F. , but only 2 strength lost The difference between the original jelly 40 at these two temperatures was plainly evident but less pronounced in the fresh apple extracts. The figures are shown in Table IX. An indication of the rate of deterioration during storage of the jellying pectin can also be obtained from the figures of Table IX. The concentrated extracts, both poaaoe and fresh apple, show a greater average decline during the second months than during the first; the difference is greater in the extracts kept at 76 F. than in those stored at 40° F. On the other hand, the unconcent rated extracts, both fresh apple and pomace, showed kept at both cold storage and room temperatures, the first the greatest decline in Jelly strength during twice as month, the average loss being approximately concentrated great as during the second month. Only the months, fresh a -pie extracts were stored for three month was less and their average loss during the third be judged from than during the second, as far as may seem that the results of this experiment, it would is a deterioration of unclarified ^ctinous extracts the greatest more or less serious matter; furthermore, extracts deterioration during storage of concentrated unconeentrated occurred during the second month, while the first extracts show the greatest loss during month. « ' P CJ C (0 © -rl >» O- lO O fi rH (J> » G • • lO o o o C. J t» © © £ E3 » CO © -H >» *4< tO to rH O <*> 00 to 93 r> o o O * • rH » a • • • • • • CM rH •o to to o- rH u c (4 » tO to © aj ©co rH jS U O P c -3 m CO to t> to CO CJ» o «0 © CM 06 rH p U r-i O © © «H rH-* to Cv to O 00 CO o ° rH to to f> rH rH CM as • 33 • • • • • © to • • f-i rH o EO w •* ts © oo CM ~. _J LO hK© >» P. 03 e tiJO ts lO rH CM to to CO as U e « LO CO « CM S3 O © t-i DO cj p O h >> 83 fl to o rH CM CO CO rH CM c ja 3* Storage Life of Clarified Extracts In this discussion only the extracts clarified other by enzyme treatment are considered, since all extracts methods failed. Although none of the clarified viscosity remained in storage longer than one month, the good measurements at the end of that time gave a on the storage indication of the effects of clarification the completely life of pectinous extracts. Not only which the attempts clarified juices, but also those upon less unsuccessful were at clarification were more or cloudy and after stored. Some of these were equally as deep as any storage contained a layer of sediment as cloudy than the unclarifled extract. Others were less totally clear, unclarified extracts, but still were not -completely" remaining rather turbid and opaque. A turbidity and no clarified juice is one which has no and almoet transparent, sediment, but is absolutely clear the light. one that "sparkles" when held to clarified extract, in general, it was found that least during the retained jell strengih better, at the unclarified. flret month in storage, than dia made no difference Apparently the storage temperature jell strength. In several in the loss or retention of juices clarified in instances, as shown in Table X, cj cm p r-l A o o 00 CO a « p o o to to o o CM CM • © fi « ii • • # o •«-< c a o o H r-l © P 3 i .GOOto P ZO P oo CO CO eo io OJ cm OJ o» cm cm IS t> CO CO ri s 'I cm cm > © P Vt (C a 23 <5 ^5 o o cm cm cm sm cm cm itj m mm © c» © o» r- o o CM CM CM CM CM .M hh id m rH o o to o a) O tO O to o P o -5 >t3 •a P © p © © © © © © o P o P rH P r-i P p K © « « cx © Pi © © E E c. u -p -p < *> < p ~P © a «> a m H © C3 o © o © © XI ® o © to « o © o 6. O 0) © o c s o © C © E2 B c o o o ^ o >• c o o o Pi to 43 40° F. and at 70° F. the same manner and stored at at the end of the having the same initial viscosity, the loss of jelly month showed exactly the same loss, did, however, to a strength of the various extracts degree of complete- certain extent coincide with the the more complete ness of clarification accomplished, deterioration suffered the clarification the less the The completeness of by the extract, and vice versa. however, for, clarification was not the only factor, the average unconeen- as in the unclarified extracts, greater percentage of its trated pomace extract lost a of the others. There original jelly strength than any life of the extracts w no difference in the storage with the different clarified under the same condition, the determining factor diastase preparations used; brand of diastase used, seemed to be not the particular clarification accomplished. but the completeness of the loss in jelly strength Table XI shows the average pomace storage by extracts of suffered curing one month different with enzyme under the and fresh apples treated the varying degrees of conditions which resulted in all treatments a concen- clarification described. In of the per cent of the weight tration of enzyme of 0.1 and the extracts were unconcentratsd extract was used, oeriod as described in the filtered after the conversion m «o o o oJN Oi O £0 C- S3 O « • • • CM «* tO to 80 O <0 N CO lO • • * r-t H r-4 m c- to o» I 0 c •H © +» O 0 fi ©megi-l © © i-( >, co tJ t> © © >» cc o « O HHHo >» © M I* -4 S) r-4 © > :o > -© © © M +2 C ^3 © © © P. C t, CO 3 u E=4 < O 43 discussion on clurif icatioa. The figures of Table XI, when compared with those of Table IX, which shows the loss of jell strength curing storage of unclarified extracts, clearly indicate the advantages of clarification of a T»ectinou8 extract before storage. Whether the minute deterioration suffered by completely clarified extracts curing the first raonth in storage indicates an ultimate smaller total jelly strength loss than in the unclarified extracts, or merely a slower rate of deterioration, is ooen to conjecture. Whichever is the case, the advantage is still with the clarified extracts. When clarification was not complete, however, no advantage was gained; on the contary, the initial loss of jelly strength inexplicably suroassed that of the unclarified extracts. 44 J?. DISCU8SI0S Of THE P08SI8II.ITII8 OF HOME ?RE?ARATIOH AND UTILIZATION OF AFPLK PECTIH EXTRACTS The extraction, clarification, and preservation of apple lectin extracts by the methods found most advan- tageous in the work done on this research problem is a fairly simple prooeedure, one which requires no great technical skill or training. The most difficult part of the preparation of the extracts is likely to be the clarification, because it requires the use of special materials and equipeient, namely, an enzyme preparation, Filter-Cel, and a filter pump. For the housewife who desires to prepare relatively small amounts of pectin, sufficient only for her own general use, it might be more practical to omit the enzyme treatment and store the extracts uaclarified, although such an extract will lose jelly strength during storage, and because preparation of its cloudiness cannot later be used in the owner of good quality products, fmt to the orchard operator for and to the farm factory or cider-mill valuable use whom the extraction of oectin provides a of the for olnerwise waste products, an investment is equioment and material required for clarification inferior essential. Without olarifioation his pectin is and oannot compare with commercial extracts and con- 45 centrates now on the market; clarified, it is their equal. There are endless ways in which pectin extracts and concentrates can be utilized to advantage in the home; probably their most general use is in jam and Jelly making. Pectin concentrates are used in the production of synthetic sugar-acid-pectin jellies artifically colored and flavored, but their more general home use is in bolstering the jelly strength of juices extracted from fruits of low nectin content. Pectinous concentrates can also be used to increase the jelly yield of an extracted Juice and reduce the cost of the nroauct; the more nectin present the larger the amount of sugar that will be Jelled, and therefore the greater the yield. Furthmore, with a large amount of sugar present a small evaporation of water will be required to bring the sugar concen- tration to the ue8ired amount, thereby reducing the cooling time and Improving the color ana flavor. However, the addition of too much extra pectin and sugar will mask the flavor of the finished jelly. Jams, conserves or marmalades of a naturally weak or watery consistency can be thickened by the addition of small amounts of pectin. 41 The amount of pectin necessary to add to any easily juice to be used for jellies can be most made determined by viscosity aeasurements of the juice is cheap with Baker's (1934) jellmeter. the jellmeter convenience, and easy to use, ana, for the sake of amounts of with each is included a chart showing the yiela of jelly sugar necessary to add to, and the final obtainea from a unit weight of juices of varying concentrate, viscosities. Si this manner, a. pectin any juice regardless of its viscosity, can be adaed to the desired until the viscosity of the juice reaches level. sugar Jelly formation depends not only on the acidity, a and pectin concentration but also on the jellation. The pH pH below 4.0 being required for the home without of juices could not be determined in equipment, and if the use of expensive, sr-eclalized can be deter- added acid is needed, the proper amount but if mined only by trial. Tartaric acid is oheap, unavailable, lemon juice may be used. products jelly, however, is only one of the many In the home in which pectin can be profitably used. in making manufacture of candies, pectin may be used coated pieces. jelly centers and bases for dipoed or without When properly made such candies keep fresh 4? becoming sticky, are tender and firm, and of clear and sparkling color. Any kind of liquid sauce or fruit juice cocktail is benefitted by the addition of pectin. Sauces for puddings or ice cream dishes become thicker and heavier, conveying the impression of richness, when they contain pectin. Fruit juice oocktails receive added body and an improved physicel appearance on the addition of pectin. A small concentration of pectin in beverages which contain solid material in suSTension, such as tomato juice cocktails or chocolate flovored liquids, acts as a protective colloid and, aocording to Baker, has a definite stabilizing effect, increasing the resistance of the product to separation into layers of solid and liquid. Peotin is believed to improve the texture, moisture holding capacity, and yield of baked food products, definitely slowing the staling process. Too much pectin in such products would decrease the total solids content, and, instead of slowing, would probably accelerate the rate of staling. The texture and time of set of meringues end frosting could probably be improved by the use of pectin. As a stabilizer pectin has a definite- ly esttblished place in the commercial manufacture of ices and sherbets, improving their texture and body. adapted to home Since ices and sherbets are best classified as production of any of those products method for home utilization of •Ice Ore**" , another the already generous pectinous concentrates is MM to list. dissolving Difficulty is often experienced in pectin having * tendency dried pectin -reparations, the gelatinous mass. Ho such diffi- to clump together in a use of liquid concentrates; culty is encountered in the suffices. The limiting factor a thorough mixing always concentrates is the flavor in the use of apple pectin or Jams this is imparted by its addition. In Jellies but in some of its not noticeable or objectionable, products, ices and other uses, such as in baked food apple pectin concentrate sherbets, and beverages, the off-flavor if used in too large Bay cause n decided products the desired con- amounts. However, in such *ould not affect centration is very low and probably degree. flavor to a very noticeable waste product can be The fact that an otherwise production of utilized in the easy and inexpensive and the variety of opportun- apple pectin concentrates, the home would seem to ities for its utilisation in undertaking for the make its preparation a profitable owner, and the farm housewife, the farm and orchard factory or cider-mill owner. 49 V. SUMMARY AND CONCLUSIONS 1. Determine tioix wes made of the optimum conditions for the extraction of pectinous juices from cull end grade C Baldwin apples, and from apple ponece from Baldwin and King apples. The extraction conditions considered varied as to fruit to water ratio, time and temperature of extraction, and the addition of organic acids. 2. Determinations of pectin were not made by analytical methods; instead measurements were taken of relative viscosity, of which, according to Myers and Baker (19E7) jelly strength and dependent jelly yield ere functions. The method proved very successful, the viscosity being in all cases a relatively accurate indication of the jelly strength or suger supporting capacity of the pectinous extracts. 3. In fresh apple extractions e fruit to water ratio of 3:3 and two 15 minute extractions at 212° F. , v/ith the addition of 0.2 per cent by weight of tartaric acid produced a combination of large juice yield end high jell strength, which resulted in the greatest total jelly yield. 4. The addition of 0.4 per cent of tartaric acid to the extraction water was slightly less efficient under 50 otherwise similar extraction conditions than s concentration of 0.£ per cent acid. The non-acid extraction under conditions the same as employed in the acid extractions was less favorable for Jelly yield than either of the acid extractions. 5. Three extraction periods, two periods of 30 minutes each, fruit to water ratios of 3:2 and 3:4 and extraction temperatures of 240 F. and 190° F. were all far less efficient than the acid extraction. The last mentioned resulted in a total jelly yield approximately 30 per cent less than the 0.2 per cent acid extraction. 6. In pomace extractions the same variations as in fresh apples were employed, hut the pomace to water ratios were 1:6, 1:12 and 1:16. Two 0.4 per cent acid extractions of one part pongee in 12 parts water, for 15 minutes at 212° F. produced a juice having the largest jelly yield. The yield obtained from the same pomace to water ratio twice extracted at 240° F. for 15 minutes without the addition of acid was only 10 per cent smaller. 7. A third extraction served only to seriously reduce the total jelly yield, except in the 15 minute 212° F. 51 extraction of a pomace to wrter ratio of 1:6; the yield from the three combined extracts in this case was only 3 per cent less than that obtained from the first two combined. 8. From two extractions of a ratio of 1:12 a jelly yield was obtained only 2 per cent greater than from two extractions of a 1:6 ratio under otherwise similar conditions. The 190° extraction, the 1:16 pomece to water ratio and the 30 minute extraction all were less than 50 per cent as efficient as the acid extraction. 9. Methods of clarification of apple pectin extracts were attempted. The use of diastase preparations was found very satisfactory in removing cloudiness due to starchy materiel in suspension. Medicinal diastase, U.S. P. end two commercial preparations, "Protozyme PX" and "Clarase" succeeded equally in clarifying under similar conditions. not reduce the 10. Although fermentation by yeasts did viscosity of the pectin extracts, as e means of clari- fication it was unsuccessful, pasteurizing 11. Processing at 212° F. for 10 minutes or b11 st 176* F. for 10 minutes were successful in instances in effecting sterilization of the extracts 53 bottled in half pint jars. Of the extracts which were filled hot, sealed find stored without further theaaraal treatment, the concentrated kept unspoiled, but about 75 per cent of the unconcentrated showed a surface mold growth within three weeks. 12. Preservation with sodium benzoate was e failure. Addition of 0.05 per cent sodium benzoate failed to prevent surface mold growth after ten days. A con- centration of 0.1 per cent sodium benzoate prevented mold growth in all concentrated extracts and in helf of the unconcentrated extracts, but after ten days' storage the viscosity in every case was reduced by about helf. 13. Viscosity of unclarified pectin extracts decreased during two months' storage, the averege loss in con- centrated extracts end unconcentrated fresh apple extracts being approximately 5 per cent when kept at o room temperature and 3 per cent when stored at 40 F. Unconcentrated pomace extracts, however, lost an average of 63 per cent of their original viscosity at a storage temperature of 76° F. and 37 per cent at 40° F. 14. Concentrated extracts suffered the largest part of their total loss in viscosity during the second 53 month In storage , while the unconcentrated suffered the greatest decrease during the first month. 15. Concentrated and unconcentreted extracts completely clarified with any of the three diastase preparations used, lost less than 1 per cent of their original viscosity during one month in storage. SxtraotS which were not successfully clarified, however, suffered a greater loss during the first month in storage than the unclarified extracts. 16. The storage temperature mpde but slight difference in loss of viscosity of clarified extracts. Several instances were noted in which extracts having the same Initial viscosity suffered identically similar losses during the same periods of storage at 76° JP. and at 40° F. 17. The possibilities of home preparation and utilization of apple pectin extracts were briefly discussed. It was concluded that, owing to the ease of preporetion of pectinous extracts end the variety of ways in which they may be used, their preparation would be practical end profitable for the orchard owner, the farm factory or cider-mill operator and even for the housewife. 5^ VI. BIBLIOGRAPHY Ahmann, C. F. and Hooker, H. D. , 1925. The Estimation of Pectin and a Study of the Constitution of Pectin. Missouri Agr. Exp. Sta. Research Bull. 77. Baker, G. L. , 1934. Improved Methods of Jelly Man- ufacture. Canner. 80, 6, 19-21, 24. Baker, G. L. , 1934. The Treatment of Apple Pomaoe for Pectio Extraction. The Fruit Products Journal, 1934. 14; 110. Baker, G. L. , 1935. Pectin in Nature and Industry. The Scientific Monthly, 1935. 40, 48-54. Baker, G. L. and Kneeland, R. F. , 1935. Pectin Content of Raw Materials - Optimum Conditions of Extraction Determined by Viscosity. The Fruit Products Journal. 14, 204-5; 210; 220. Baylies, W. H. , 1925. The Mature of Enzyme Action. Longmann, Green ana Oo. , London. Second edition. 1-43. Barker, B. T. P., 1918. Tectous Extracts. British latent So. 125,330. Bell, J. C. and Siegand, E. H. , 1925. Extraction and Lariflcation of Pectlnous Fruit Juices. Oregon Agr. Exp. Sta. Giro. 63. Bender, f, A., 1929. Pectin. Canadian Patent No. 286,300. (to Douglas Packing Co., Ltd.) Beylik, F. G. , 1922. Pectous Material from Plant Substances. U. S. Patent No. 1,393,660. Caldwell, J. S. , 1917. A New Method for the Preparation of Pectin, tfash. Agr. Exp. Sta. Bull. 298. California Fruit Grower's Exchange, 1929. Pectin Preparation. British Patent No. 355,130. California Fruit Grower's Exchange, 1930. Pectin. French Patent No. 699,852. Campbell, C. H., 1922. Jelly. J. Ind. Eng. Chem. 12, 558. &5 of Commercial Camobell, C. H. , 1925. Some Phases Jellymaking. Canning Age. 1935, 347. from Protein and Crawford, S. L. , 1924. Pectin Freed Starch. U. S. Patent No. 1,507,338. Jelly Investi- Cruees, V. and MoMair, J. B. , 1916. gations. J. Ind. Eng. Chem. 8, 417. Pectin Darling, E. R. and MaoKillen, H. F. , 1931. Solutions from Apple Pomace. U. 3. Patent NO. 1,799,140. Davidson, 0., 1925, Pectous Extracts from Fruits and Vegetables. U. S. Patent Ho. 1,538,077. 1923. Denton, M. C, Johnstin, K. and Yeatman, F. homemade Apple and Citrus Pectin Extracts ana their Use in Jellyraaking. U. S. Dept. Agr. Circ. 254. atent Deutches Pektinges, 1928. Pectin. German 1 No. 565,242. Pectin. U. S. Doel, T. W. and Maes, L. A. F. , 1921. Patent No. 1,385,525. Pectin. British Douglas, R. , 1915. Jams and Jellies; Patent No. 6,497. of Apple Juices Fellers, C. R. , 1928. The Extraction in the Manufacture of Jelly. Mass. Agr. txp. Bta. , Tech. Bull. 15. of Jellymaking. Goldthsaite, N. E. , 1909. Principles J. Ind. Eng. Chem. 1, 333. of Jellymaking. Goldthw^ite, N. E. , 1910. Principles J. Inc. Eng. Chem. 2, 457. of taking Fruit Goldthwaite, a. E. , 1925. Principles Bull. 3y». Jellies. Colorado Agr. Exp. Sta. , Preparation Griggs, M. A. and Johnstin, R. , 1926. Pectin. J. Ind. and Colloidal i roperties of Eng. Chem. 18, 623-25. Pectin. Hunt, C. K., 1918. ISethod for Preparing Science, 48, pp. 201-202. 56 Patent No. Leo, H. T. , 1921. Fruit Jelly. British 188,387. New and Magoon, C A. and Caldwell, J. S. , 1918. Improved kethod for Obtaining lectin from Fruits and Vegetables. Science, 47, 592-94. Mehlitz, a., 1926. Decomposition of Pectin. Konserven-Ind. (2) 13, 1-3. ^ithoff, H. C, 1934. Pectin-containing Products. U. S. Patent No. 1,976,741. (to Standard Oil Go. of Calif.) Patent No. 1,398,339. Monti, E. , 1922. Pectin. U. 8. Fruit Jellies, . Baker, G. L. , 1927. Myers, I B. and V. The Role of Pectin, 1. The Viscosity and Jellying Properties of Pectin Solutions. L»el. Agr. Exp. Sta. Bull. 149. Jellies. Myers, P. B. and Baker, G. L. , 1929. Fruit VI. The Role of Pectin. 2. The Extraction of Pectin from Pectic Materials. Del. Agr. Exp. Sta. Bull. 160. Jellies. Myers, P. B. and Baker, G. L. , 1931. Fruit VII. The Role of Pectin. 3. The Effect of Temoerature upon the Extraction of Pectin. Del. Agr. Exp. Sta. Bull. 168. pectin. U. S. Patent Nanji, &- R. , 1927. Extracting No. 1,634,879. and Paine, H. 8., 1922. The Use of Pectin in Jam Jellies. JUB. Food Jour. 17, 11-13. Pectinerie du Eervor, 1927. Pectin. French Patent No. 645,993. Presence of Starch in Perrier, S. , 1924. The Normal Pectic Juices Used in Jam taking. Ann. fals. 17, 208-211. Solutions. German Patent Piator, L. , 1935. Pectin No. 608,036. ) . 57 Ripe, R. , 1929. Removing Starch from lectin Solutions. Jerman Patent No. 547,806. (to Pomoain- !;»erke G.K.B.H. Rooker, I. A., 1927. Hew Usee for Pectin. Fruit roaucts J. and A». Vinegar Ind. 7, 11-13. Schw&rtauer, Honigwerke und Zuckerraff inerie, A.-G., 1927. Pectin. Eritish Patent No. 281, 513. Waldechmidt-Leitz, E., 1929. Enzyme Action and irooertiee. John SSiley and £;one, Inc., H. Y. 1-6; 198-209. ifllBon, 0. P., 1925. The Manufacture of Pectin. Ind. Eng. Chem. 17, 1065-1067.