A CHEMICAL STUDY OF CRANBERRIES 



91 



Tahle 1. — Composition of Cranbehries while ripening on vines — 1926 



EARLY BLACK 



Date 



Aug. 31 



Sept. 2 



Sept. 9 



Sept. 15 



Sept. 23 



Sept. 29 

 Oct. 7 



Starch 



.14 

 .15 

 .14 

 .15 

 .12 



nearly eqiual jrain in dry matter. The acidity of the cranberry does not vary 

 niucli during the de\elopnient on tiie vines. There are reported to be at least 

 three acids in the cranberry, of which citric is estimated as constituting four- 

 fifths of the total, with malic about one-fifth, while benzoic acid has never 

 been found to reach 0.1 per cent of the fruit. So for convenience the acid 

 is measured as though it were all citric. 



The waxy substance was extracted by carbon tetrachloride and exists 

 principally in the skin of the fruit, rendering it nearly waterproof. The 

 figures make it appear that wax increases slightly while the fruit develops 

 and fiber and protein decrease a trifle. When measured in percentages of 

 air-dry matter these changes are much more pronounced and significant. 



Starch constituted such an insignificant percentage of the fresh berries 

 that it may have existed only in the seeds. The important fact is that no 

 significant amount of sugar could be formed from starch during storage of 

 the cranberries, and therefore the sugar in them must be formed while the 

 berry is attached to the vine. 



Recent studies by Hawkins (7) of the ripening of grapefruit have shown 

 a decrease in acid as the fruit matures on the tree, but a marked gain in 

 total sugar. 



Table 2. — Co.'mposition of cranberries while ripening on vines — 1927 



Variety 



Dry 



matter 



Total 

 acid 



Total 



sugar 



Wax Protein 



Early Black. 



Howes. 



1.34 

 LSO 



1.22 

 1.50 



1.43 



1^47 



Changes in Composition of Cranberries after Removal from the Vines 



Eight varieties of cranberries were received from Dr. H. J. Franklin on 

 October 20, 1927. There were about four quarts of each variety and the 

 packages were placed in an electric refrigerator maintained at temperatures 

 around 40° F. Samples of each variety were analyzed early in November for 

 dry matter, total acids and total sugar. Four of the varieties were analyzed 



