70 MASS. EXPERIMENT STATION BULLETIN 339 



Hort. Sci. Proc. 33: 627-633. 1936). At the present time a second season's 

 work on spinach is under way. Raw spinach loses considerable amounts of 

 vitamin C in cooking and in the processes incidental to freezing and canning. 

 Thus, fresh spinach containing 400 units per ounce is reduced to 250 after cook- 

 ing and to approximately 100-150 units in the cooked frozen spinach. The 

 vitamin A of spinach is well retained after freezing or canning. 



Blueberries. (Oreana Merriam and C. R. Fellers.) A paper has just been 

 published (Food Research 1: 501-512. 1936) on chemical and nutritive studies 

 on blueberries. Both Vaccinium corymbosum and V. pennsylvanicum were 

 used, as well as several cultivated varieties. No marked differences in com- 

 position or content of vitamins A and C were found. Freezing the fruit had 

 no effect on these vitamins. Some of the canned blueberries showed good re- 

 tention of vitamin C. Blueberries are fair antiscorbutics. The average vita- 

 min C content is from 1 to 2 units per gram. The vitamin A content is low, 

 e.g., 0.2 international unit per gram. 



When blueberries were fed to normal young men no increase in urinary acidity 

 or lowering of the blood alkali reserve occurred. Only traces of benzoic acid 

 could be obtained from blueberries. 



Work is in progress on methods for the manufacture of blueberry cordial and 

 other products. 



Tomatoes and Tomato Juice as Antiscorbutics. (W. A. Maclinn, C. 

 R. Fellers, and R. E. Buck.) In cooperation with the Department of Oleri- 

 culture, 98 distinct varieties and strains of tomatoes were grown on the campus 

 plots. Six fruits of each variety were examined for ascorbic acid content 

 (vitamin C) by the chemical method. Earlier work had shown that results 

 obtained by the 2, 6-dichlorophenolindophenol dye titration method agreed 

 well with the results obtained by the standard guinea pig bioassay. Marked 

 variations, from 75 to 250 units per ounce, were observed. Richest of all 

 tomato strains tested, were new Waltham Field Station crosses and selections. 

 Marglobe and Stone varieties were good carriers of vitamin C, but Rutgers 

 and Pritchard were relatively poor. No losses in vitamin C occurred during 

 storage so long as the fruits remained sound and firm. Similarly, degree of 

 maturity had no effect, as partly green tomatoes contained as much vitamin 

 C as fully ripe fruits. 



Tomatoes lose 50 percent or more of their original vitamin C in the process 

 of manufacture into juice. The factors responsible for this loss are being 

 studied experimentally. Some of the results of this investigation are in press 

 in Amer. Soc. Hort. Sci. Proc. 1936. 



Home Canning Research. (C. R. Fellers, W. A. Maclinn, and A. S. 

 Levine.) The results of these investations insofar as pressure- vacuum relation- 

 ships in the jar are concerned have been prepared for publication. However, 

 many data on oven-canning have been collected and will be made public in 

 bulletin form during the year. On the whole, oven canning is a dangerous 

 and unsafe method of food preservation. 



Another year's experience with cooperators throughout the State has dem- 

 onstrated the utility and soundness of the new method of processing glass 

 jars with the lids firmly clamped down. Less liquid is lost during processing 

 and the appearance of contents of the jars is greatly improved. There is also 

 a saving of time and less danger of getting burned while clamping down the 

 wire bails while the jars are still very hot. Breakage of jars is not increased 

 by the use of this method. It can be fully recommended for use by home 



