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TECHNICAL BULLETIN 15 



Chart 1. Relative Amounts of Total Soluble Solids, Pectin and Acid Recovered in 

 each of Three Sucessive Extracts and in the Residual Pulp. Random Tests. 

 Temperature of Extraction 100° C. Ratio of Sliced Apple to Water 3:2. 

 No Added Acid. 



Black — first extract 



Doable crosslines — second extract 



Single crosslines — third extract 

 White — residual pulp 



SOLUBLE SOLIDS PECTIN MALIC ACID 



*Boiled 15 minutes and allowed to stand 10 minutes. 



Thus Chart 1, constructed from individual tests, pictures the relative per- 

 centages of soluble solids, pectin and malic acid obtained in successive ex- 

 tracts under a constant set of conditions, i. e., temperature of extraction, 

 ratio of apple to extraction water and acidity, while only the extraction 

 period was varied. In this manner it was possible to determine the influence 

 of these several factors upon yield and composition of the juice obtained 

 from each successive extraction. 



The limits in percentage for soluble solids recovered in the first, second, 

 third extracts and remaining in the pulp were respectively 33.0 — 66.8, 17.0 — 

 31.6, 4.4—19.7, and 3.3—22.9. For pectin, these limits were 21.5—64.0, 10.8— 

 33.2, 6.0—22.2, and 7.9 — 43.9; and for acid calculated to malic they were 

 34.9—82.3, 6.1—43.1, 4.5—26.2, and 2.0—31.2. 



The relative lack of variation of solids or pectin in the second and third 

 extracts regardless of the treatment is particularly emphasized in Charts 

 1-5. In fact one of the outstanding results of this investigation was that 

 juice could be extracted successfully from apples by almost any method, 

 though with unlike results. It is fortunate indeed tiiat this is true, because 

 every conceivable method of juice extraction is practiced in the home and 

 factory. The wide limits within which a degree of success may be attained in 

 preparing apple jellies, for example, makes total failure difficult, though 

 improvement in yield and quality always can be secured by the use of 

 correct methods. 



