STARCH. 35 



but not sufficient to preserve it. before being worked up into the fin- 

 ished product. When this procedure is followed the use of some 

 form of preservative is necessary. Canned fruits, on the other hand, 

 are put up as fast as they are supplied to the factory, and hence need 

 no artificial preservation. 



Salicylic acid and benzoic acid or the sodium salts of these two acids 

 are the preservatives most commonly employed with fruit products, 

 and were found to be present in more than half of the jellies and jams 

 examined, while the percentage of canned fruits found to be artificiall}^ 

 preserved was comparativelv small. 



STARCH. 



The presence of starch in fruit products may be attributed to one of 

 two sources: It may have been added as such to jellies, and possibly 

 jams and marmalades, in order to give them the proper consistency^ 

 when converted by heat and moisture into paste, or it may have 

 been normally present in the fruit used as a basis for the product. 

 The ordinary means of detection afford no basis for determining 

 to which source the starch found in jellies is due. With jams and 

 marmalades from which portions of the fruit are still obtainable a 

 microscopic examination will reveal whether the starch is normalh' 

 present, as a larger part of the starch remains within the cell walls 

 after the fruit has passed through the various stages of preparation. 

 With jellies, however, if the amount of starch added has been small 

 and the product has been thoroughly heated subsequent to its addition, 

 or if the fruit from which the jelly was made contained starch, the 

 starch, in the iinished product, will be present in a soluble form. 

 Only when an excessive amount has been added or when the boiling 

 has not been sufficient to bring all the starch into solution can the 

 addition be detected with certainty. Many jellies, of course, are made 

 up pureh' artilicially or with the use of only small amounts of fruit. 

 In such cases the polarization and the per cent of dextrin present will 

 reveal the character of the goods, and any appreciable amount of 

 starch in such products ma}' be considered as having been added. 



Considerable amounts of starch are normally present in the apple, 

 and probably some similar fruits, but the content gradually diminishes 

 during ripening, and finally disappears in the thoroughly matured 

 fruits. With the small fruits, on the other hand, starch is seldom 

 found to be present in more than traces, even when these fruits are 

 too green for use. As a result, pure apple jellies may contain con- 

 siderable amounts of starch, while the pure jellies from the small fruits 

 show no starch reaction. Not all pure apple jellies, however, contain 

 starch, as the product ma}' have been made subsequent to the complete 



