Agricultural Research lx New Hampshire 17 



oxidizing material. This latter sample acts as a blank solution, and any 

 flourescence value found is subtracted from that of the other sample in 

 order to arrive at the true thiamine content of the substance being 

 analyzed. 



Thus, current investigational work is concerned with pure solutions 

 of thiamine and ^^'ith similar solutions to which have been added certain 

 of the other water-soluble vitamins. This fundamental approach ^\■as 

 deemed necessary in order to ascertain the effect of the blocking agent 

 used. The results indicate that this procedure is indeed satisfactory for 

 the assay of such pure solutions. Since different fluorescent readings 

 were obtained when different lots of stock solutions were used, how- 

 ever, it appears to be a necessity that standard thiamine solutions are em- 

 ployed for purposes of calibration each time unknown solutions are 

 assayed for thiamine. 



Since the procedure being studied appears satisfactory for pure vi- 

 tamin solutions, it is intended next to examine its applicability to various 

 foods and biological fluids. 



Factors Affecting the Nutritive Value of 

 Nev^^ Hampshire-Grown Fruits and Vegetables 



(Also a Home Economic Project) 



The Effects of Quick-Freezing on the 

 Vitamin Content of Strawberries 



In 1943, it was noted that the Catskill variety of berries, while not 

 containing the highest amount of ascorbic acid of the several varieties 

 studied, retained the largest amount of ascorbic acid after freezing and 

 storage. Hence, this was the variety chosen for further study. 



Field samples were taken for immediate analysis at the time of pick- 

 ing, and the remainder were stored until such time as they would normal- 

 ly reach retail trade. At this time a sampling was made of the entire lot 

 for immediate analysis, and other samples Mere removed to studv the 

 effect of holding at room and refrigerator temperatures, thus simulating 

 the actual practice in retail stores. Aliquots were analyzed after 12- and 

 24-hour periods. The remainder were prepared for preservation by 

 washing and hulling, an aliquot being removed for analysis at this step. 

 Three methods of preservation by freezing were used: (1) in 50 per cent 

 sugar syrup, (2 ) whole dry pack, and (3) blanched prior to freezing 

 whole dry pack. An aliquot of the blanched berries, and aliquots of all 

 frozen packs were analyzed after 12 hours of quick freezing and at Yz, 3, 

 6, and 9 months of storage. 



In 1944, the fresh Catskill sample contained 90.5 per cent moisture 

 and 49 7Jig. ascorbic acid per 100 grams (fresh weight); whereas, in 1943, 

 the Catskill samples, harvested at three different times, ranged from 88.6 

 per cent to 90 per cent moisture and 64 to 78 vig. ascorbic acid. There 

 appeared to be no loss in ascorbic acid content from the time the berries 

 were harvested (field sample) until they were washed and hulled prepara- 

 tory to preserving. The only loss in samples held to simulate retail prac- 



