University of Massachusetts Amherst ScholarWorks@UMass Amherst Masters Theses 1911 - February 2014 1939 Studies on the canning of apples in syrup. Andrew A. McCornack University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/theses McCornack, Andrew A., "Studies on the canning of apples in syrup." (1939). Masters Theses 1911 - February 2014. 2770. Retrieved from https://scholarworks.umass.edu/theses/2770 This thesis is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Masters Theses 1911 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. - A.vVv . McCORNACK -1939 STUDIES OM THE CANNING OF APPLES IS 3YHUP J “Vs t. Andrew A. McComaek Thesis submitted for the degree of Master of Science MASSACHUSETTS STATE COLLEGE, AMHERST May 24, 1939 Table of Contents Page Introduction 1 Review of Literature 2 Experimental Studies 6 It Details of Manufacture 6 A. Deaeration of the Apple g B. Percentage of Syrup for Canning Apple Slices 13 C. Method of Sealing Cans 14 D. Heat Penetration Studies 14 Type of Can 15 II. Consideration of Varieties 16 A. Apple Waste Data IS B. Weight Data IS III. Special Uses of Apples 19 A. Use in Fruit Salad 19 B. Apple Rings and Dices 20 IV. Use of Additional Substances 21 A* Addition of Acids 21 B. Addition of Honey 22 0. Use of Dextrose 23 V. Retention of Vitamin C 23 1839 - g MOV Summary 2k Conclusion 26 Bibliography 27 INTRODUCTION Apples (Pyrus malus) have long been appreciated as a food popularized by an attractive appearance and a delicious flavor. In spite of the economic Importance of apples, relatively little has been done on their canning for dessert purposes. This is due to the fact that the canning of apples presents difficulties not easily overcome. Then too, the flavor of canned apples, while pleasing, does not have the ap >eal of many other canned fruits. The better grades of fresh apples are stored under the best known conditions for their long preservation so that they can be marketed over a period of several months. The lower grades, though unsuitable for fresh use are made into high grade ap le products. It is from these lower grades that a canned product would be manufactured. In recent years many apple by products have been developed. Cider is bottled, and consumed at all seasons of the year. Many types of fermented apple Juices are now on the market. New uses of apples are in breakfast foods and in medical work. This study was made to find a method of canning apples in syrup. The product resulting therefrom could be success¬ fully sold commercially as a dessert product. Canned apples as a dessert product can be defined as peeled and cored rings, slices, cubes or other shaped -2 pieces In syrup. The finished product Is fir®, yet tender and will retain Its shape. A canning procedure was developed using one variety of apple. All Kew England varieties which were available were canned with different degrees of success by this method. Technical procedures such as the sugar syrup con¬ centration , heat treatment and use of additional substances for Improving the flavor were studied. REVIEW OF LITERATURE There are a number of reports on the subject of canning apples as apple sauce and solid pack apples for pies, but none apply direotly to the problem of canning apples in syrup as a dessert product. Campbell (1937) has written a rather complete abstract of the various methods which are now employed in the canning of apples. The factor that makes apples difficult to can Is the quantity of air in their porous tissues. The oxygen reacts with the tin and iron in the presence of the fruit acid, to cause ‘•pinhollng* and swelling of the can. The tin plate is usually acted upon most vigorously at the water or syrup line. To successfully can apples most of the oxygen, if not the other gases, must be expelled before -3- the lid Is sealed, Caapbell (1937), fhe air In the apple Is composed of approximately 15*6 percent carbon dioxide, 12.6 percent oxygen and 71*& percent nitrogen. This ratio varies during storage. As storage continues the volume of carbon dioxide increases, Morris (1933). Caapbell (1937) reports that 500 grams of apples at o 212 F. gave off SO cubic centimeters of gas in 15 minutes. During the first five minutes 6S cubic centimeters of this gas were given off. On analysis It contained* 15*6 percent carbon dioxide 22.7 percent oxygen 79*3 percent nitrogen Steaming the apples without soaking them reduces the oxygen content of the fruit materially, Morris (1933)* The methods given by Caapbell (1937) for canning apples are as follows: 1. Vacuum method; The apples are prepared and placed in special retort baskets which are plated to prevent dis¬ coloration of the fruit by contact with the Iron. A lid is placed over the apoles to keep them submerged. The basket Is lowered into a retort containing water at 120°F. The retort la then closed, and the air is removed by a vacuum for 10 minutes. When the vacuum Is released the water fills the spaces left by the air. The apples are In¬ filled Into cans, hot water is added and the containers are sealed and processed. 2. Hot water method; The prepared fruit is submerged in water at 120°F*. for about 30 minutes. The heat drives off the major part of the gases and the oxidase enzyme consumes the residual oxygen; water then filling the spaces. 3. Steaming; (a) Prepared fruit is steamed on racks or a continuous steam blancher for about six minutes at approximately 180°F. This wilts the apples which are then filled into cans. Without sealing, the cans are placed for a short time In a retort under live steam. This removes the gases, (b) Sliced apples are placed in a retort under a vacuum of 2# to 29 inches of mercury. The vacuum is then cut off and steam is applied until the pressure reaches normal. The steam is allowed to escape and the apples are filled into cans hot or after chilling. The pieces are firm and retain all of their original flavor and aroma. This process is patented by Eugene G. Crab under United States patent number 1,557»35&* Jacobi (1926} states that E. 0. Crab1 s method of packing apples eliminates swells and perforations entirely and the fruit retains all of its original flavor and aroma. In addition the pieces retain their shape, are firm and not ragged. Morris (1933) describes the following method for 5- canning apples: If a solid pack is desired, the prepared apples are steamed until they begin to soften. In this state they are filled Immediately into cans covered with hot syrup or water, sealed and processed. Soaking apples in a two percent brine solution will expel the air through the respiration of still living tissues. This soaking of apples in brine or a five percent solution of cane sugar prevents the apple slices from turning brown. Cold water slows down the oxidation process. Prolonged brine soaking reduces the tendency of apples to become excessively soft in subsequent steaming but may cause a loss of flavor and result in a rather Insipid and salt tasting pack. Clark (1923) found that salt in canned apples tends * to Increase *pinholing*. Canned apples are easily sterilized according to Cruess (192*0 because of their high acidity, but owing to the fact that the fruit is packed tightly in the cans, heat penetration is not very rapid, nevertheless a cook of & to 10 minutes at 212°F. in an agitating continuous sterilizer Is sufficient to preserve the product. Smith and Fellers (1034) report that experimental study of 21 varieties of Massachusetts grown apples shows wide variation in vitamin C content among varieties. Seasonal or other variations, except storage, caused little change in the vitamin C content of any one variety. -6- In four to six months of storage at 36 F. Baldwin apples lost about 20 percent of their vitamin C content; in 8 to 10 months the loss was nearly percent. Fellers, Cleveland and Clague (1933). Delicious apples stored at 32°F. were found by Batchelder (193**) to evidence no loss of vitamin C over a period of six months storage. Storage at 45°F. for three months resulted in a loss of about one-sixth of the original vitamin C content. At the end of six months storage this lose had Increased to one-fourth of the original vitamin content. Todhuntar (1936) reports that a storage temperature of above 3^°F. permits changes In the apple and a resulting lowered ascorbic acid content, Delicious apples stored at 45°F. for 12 months will retain some ascorbic acid; but the loss during storage amounts to over 50 percent. Apples after peeling have only one-half to three-fourths the ascorbic acid content of the same weight of unpeeled apples. EXPERIMENTAL STUDIES To facilitate the solving of this problem it seemed best to choose one variety of apple as a standard on which to do most of the preliminary experimental wor&. Northern Spy, a good flavored, fir*, oooklng apple, was chosen as the variety to use In developing a Method of successfully canning apples ae a dessert product. The review of llteratue contains several Methods for canning apples as sauce and solid pack products. Those Methods that seeaed plausible for producing a fIra sliced dessert apple were tried with varying degrees of success.