APPLE JUICE EXTRACTION FOR .JEI.I.Y 2J3 



a variety were made and the average taken. Baldwin ai)i)k's were analyzed 

 at approximately the same degree of maturity for three successive years. 

 All these data are presented in Table 1.* 



The composition of the Baldwin apple varied somewhat from year to year 

 though these differences were not striking. In 1925 and 1927 there was a 

 small amount of residual starch even in the mature fruit. It is possible tiiat 

 ■this may be the cause of the cloudiness which is often associated with Bald- 

 win apple jelly. The pectin is reported as pectio acid, but this figure may 

 be converted readily to pectin (alcohol precipitate) by nmltiplying by a 

 ifactor found to vary from 1.5 to 2.3. Inasnmch as the factor is not constant 

 and depends upon the amount of hydrolysis or deesterification that the pectin 

 has undergone as well as upon impurities, the pectic acid values are prefer- 

 table to the alcohol precipitate. 



The ash of the several varieties showed but little variation. Pectin varied 

 Ifrom 0.29 per cent in the 1925 crop of Baldwins to 0.62 per cent in Red 

 Siberian Crab. Starch was usually present only as a trace in mature fruits. 

 Total sugars made up approximately 81 per cent of the soluble solids pres- 

 ent. The ratio of sucrose to reducing sugar proved extremely variable even 

 in the same varietj'. The insoluble solids averaged 2.5 per cent in Baldwins 

 and 2.7 per cent in other varieties. The mean aciditj- for Baldwins was 0.53 

 per cent as malic acid while other varieties varied considerably. The mean 

 pH of Baldwins was 3.46, the range for other varieties being from 3.18 for 

 Red Astrachan to 3.6 for Mcintosh. Shaw (14), Bigelow, Gore and How- 

 ard (4) and Alwood, Davidson and Moncure (1) reported analyses of a 

 large number of varieties of apples grown in different localities, at several 

 stages of maturity and during storage. For a more complete discussion of 

 the chemical composition of the apple, reference should be made to those 

 reports. 



STUDIES OF THE EXTRACTED JUICE 



Yield and Composition of Extracted Juice per Unit 



Weight of Apples 



Although analytical data were obtained on three successive extracts and 

 the residual pulp as well, only two extracts are usually considered here. 

 Ordinarily in jelly making, only two extractions are made. The third ex- 

 traction usually yields a juice which is too dilute to concentrate and use 

 economically for jelly. Fruit flavors and colors as w^ell as pectins were 

 injured readily or even destroyed completely by prolonged heating, and for 

 this reason it was considered inadvisable to mix the third extract with either 

 fthe first or second or both. 



Table 2 was summarized from 126 tests including Baldwin, Red Astra- 

 •chan, Red Siberian Crab, Wealthy, Mcintosh, King David, Winesap and 

 Rhode Island Greening varieties. Obviously the ratio of fruit to extraction 

 water greatly influenced the amount of juice obtained from a given extrac- 

 tion period. For example the mean yield increase of a 3:3 and 3.4 ratio 

 over a 3:2 was 33 and 91 per cent respectively. Hence the juice from the 

 i3:2 ratio of fruit to water was much more concentrated than the others and 

 required less evaporation to convert it into jelly. Since the pectin and acid 

 content of such a concentrated juice is relatively high, more sugar may be 

 utilized thus greatly increasing the jelly yield. In general, where the juice 

 was concentrated as in the 3:2 extract, the total amount of pectin obtained 



'The tables are presented in the appendix at the end of the bulletin. 



