58 EXPERIMENT STATION BULLETIN 354 



In studying the carotene content of the four varieties preserved by 

 freezing, it was found that vakies for the fresh berries covered a wide 

 range, all varieties being low. It was further noted that the changes over 

 a four-month storage period were not consistent. Taylor, starting with 430 

 mg. per 100 gins, fresh weight, contained only .214 mg. at the end of four 

 months ; Chief changed from .405 tug. to .285 mg. ; Indian Summer from 

 .284 uig. to .266 mg. ; Viking made no appreciable change from its original 

 value of .330 mg. 



In palatability studies over the season, the Taylor and Viking va- 

 rieties were generally preferred. The Indian Summer berry at one pick- 

 ing rated very high but at a subsequent picking was rated very low. This 

 berry w'as also very hard to handle for preserving. Palatability tests on 

 the frozen products indicated that these berries were not desirable in the 

 frozen, unsweetened condition. None of the preserved varieties remained 

 in good shape or retained good color after storage. 



III. The Effect of Canning and Quick-freezing on the Vitamin 

 Content of Blueberries 



Eighty quarts of low-bush bluelierries were obtained from a commer- 

 cial grower on August 3, arriving at the laboratory 20 hours after picking. 



When the berries reached the laboratory, 10 quarts were used imme- 

 diately for "fresh" analyses, and another 10 quarts were placed in the re- 

 frigerator to be analyzed 16 hours later, thus approximating the time the 

 berries would reach retail city trade. The remainder were either canned 

 or frozen and placed in storage for future analyses. 



In canning, the usual home procedure was followed. In freezing, the 

 same temperatures as employed with strawberries and raspberries were 

 used. Samples were canned and frozen approximately 30 hours after 

 picking. 



Blueberries lost approximately three-fourths of their ascorbic-acid 

 content between the twentieth ("fresh") and thirty-sixth hour after pick- 

 ing. The "fresh" analyses averaged 16 mg. per 100 gins, fresh weight and 

 16 hours later the average fell to 4.6 mg. 



At the end of two months storage there was no difference noted be- 

 tween the canned or frozen samples, one being 5.3, the other 5.4 mg. per 

 100 gms. of preserved product. The actual ascorbic acid content of the 

 stored samples was approximately the same as that of the samples held un- 

 der refrigeration for 36 hours after picking. 



Due to difficulties with the storage equipment, whereby the tempera- 

 tures was not maintained, data secured on the frozen product after the two- 

 month storage period are not representative of desirable storage conditions. 

 Two months later under the varying storage temperatures the frozen sam- 

 ples contained only .8 mg. ascorbic acid per 100 gms., and hence no fur- 

 ther analyses were made on the frozen berries. After six months of storage 

 the canned samples contained approximately .4 mg. of ascorbic acid per 

 100 gms. of preserved product. 



Due to the facts as noted above, blueberries will not make a marked 

 contribution to the supply of ascorbic acid in the diet. As for palatability 

 canned blueberries did not retain their flavor during storage. Frozen 



