AGRICULTURAL RESEARCH UN NEW HAMPSHIRE 57 



Frozen samples allowed to thaw for 12 hours hi the refrigerator al- 

 ways contained less ascorbic acid than the frozen samples analyzed 

 immediately. 



In all studies concerned with holding, whether fresh or frozen, the 

 samples that started with the lower ascorbic acid content held the quantity 

 originally present more tenaciously than the samples with the higher 

 original values. 



II. The Effect of Quick-freezing on the Vitamin Content of Red 

 Raspberries 



Studies, similar to those of strawberries with the exception of sugar 

 additions, were conducted on red raspberries. Ascorbic acid determina- 

 tions were run on all samples and carotene determinations were also made 

 on varieties used in freezing studies. 



The methods for moisture and ascorbic acid were the same as for 

 strawberries. Carotene was determined by the Moore-Ely method. All 

 analytical samples were taken from the blending of a representative sample 

 (approximately one pint) in a dry Waring blendor. 



Sixteen varieties were studied for varietal differences in ascorbic acid 

 content of the fresh berries, samples being analyzed from one to four times 

 during the season. Considerable varietal difference was noted but no pro- 

 nounced seasonal variation within varieties. Two varieties, Bristol and 

 Oles-Black, contained practically no ascorbic acid. Boysenberry, Marion. 

 Sodus, and one experimental cross, P-94, contained between 10 and 14 

 ing. Tacoma, Ruddy, Sunrise, Marcy, Chief, Indian Summer. Taylor. 

 Viking, and the experimental cross, P-78, contained between 18 and 26 

 nig., while only one variety, an experimental cross, G-13618, contained as 

 much as 34 mg. per 100 gram of fresh weight. 



A study of the eff"ect of holding was conducted on Chief. Indian Sum- 

 mer, Taylor, and Viking. There was a slight progressive loss after 12 and 

 24 hours at room temperature, but refrigeration for the same periods caused 

 no marked, changes. 



Four varieties — Chief, Indian Summer, Taylor, and Viking — were 

 frozen quickly and held in cold storage for four months under the same 

 conditions as the whole frozen strawberries. All varieties showed changes 

 in their ascorbic-acid content. Two samples of Taylors, one frozen July 

 26, the other July 28 did not lose proportionate mounts. The first sample 

 started with 22 uig. per 100 gms. of fresh berries and at the end of four 

 months contained 20 mg. The later sample started with 25.5 nig. and at the 

 end of the same period contained 19 mg. The amounts for the other three 

 varieties covering the same storage period are as follows : Chief, 23 nig. to 

 12 nig. ; Indian Summer, 21 mg. to 17 nig. ; Mking. 24 mg. to 18 mg. As 

 can be noted, none of these varieties contained a large amount of ascorbic 

 acid when fresh and did not change much in storage. This small change 

 shows the same tendency as was noted in strawberries, i.e., samples with 

 low original ascorbic-acid cotnent hold a large proportion of that quality 

 very tenaciously. 



At the end of the storage periods, 12-hour thawing in the refrigerator 

 produced no marked changes from the analytical results found with the 

 quick-thawed. 



