THE EXTRACTION OF APPLE JUICES IN THE 

 MANUFACTURE OF JELLY 



By Carl R. Fellers 

 Research Professor of Horticultural Manufactures 



INTRODUCTION 



In the manufacture of apple jellies, pectin concentrate, extract, or syrup, 

 it is customary to extract the juice from the fruit with water by the use of 

 heat. Whether the operation be carried on in the home or in the commercial 

 manufacturing plant, the principles involved remain the same. In the past 

 very little attention has been given to the study of extraction methods not 

 only of apples, but of all the common juice or jelly-yielding fruits. 



It is the purpose of this bulletin to present data bearing upon this problem. 

 It is not proposed to discuss cold pressed juices such as cider, because the 

 cold press is a distinctly different problem. In the latter case, very little 

 pectin is obtained in the juice, whereas in the heat extracted juice, consider- 

 able pectin is found. True, cider jelly without the addition of pectin may 

 be manufactured from cold pressed apple juice, but only by concentration 

 to one-sixth to one-eighth of its original volume. This is necessary liecause 

 of the small amount of jellifying pectin and sugar which is present in cold 

 pressed apple juice. Heat disintegrates the pectin-ricJi cell walls of fruits 

 and thus releases the pectin into solution. To a lesser degree freezing (5) 

 accomplishes the same purpose. 



Directions for juice extraction are far from standardized in that various 

 ratios of fruit to water, and diverse periods of extraction at various temper- 

 atures are reconunended. In some cases the fruit is sliced, in others pulped 

 and yet again the use of added acid to aid in the extraction is advocated. 

 Often the directions call for one extraction only, sometimes two, and occa- 

 sionally three. How is the commercial plant or the farm factory operator 

 or even the housewife to know which methods are best? The literature 

 bearing on this subject is appalling in its diversity of methods and lack of 

 orderly scientific approach. 



PLAN OF STUDY 



In order to determine the yield of juice as well as the relative amounts of 

 the three recognized jelly essentials, namely sugar, pectin, and acid, whicii 

 were extracted from apples by the use of various methods of heat extrac- 

 tion, a series of laboratory tests were conducted during 1926 and 1927 on 

 Baldwin, Red Astrachan, Rhode Island Greening, Winesap, Mcintosh, 

 Wealthy, King David and Red Siberian Crab varieties. Under standardized 

 conditions, given weights of apples were successively extracted three times at 

 <each of the following temperatures, viz. 8S^C. (190°F.), 100°C. (212° F.), 

 and 109 °C. (228° F.), respectively for 15, 30 and 60 minutes. A 15-minute 

 extraction followed by a standing period of 10 minutes, was also employed. 

 Sliced apples were compared with chopped or pulped fruit. Similarly, the 

 effect upon the extractives of various concentrations of acid added to the 

 apples was considered. The ratios of apple to extraction water, by weight, 

 were varied in this study from 3:2 to 3:4. 



