ANNUAL REPORT, 1945-46 47 



Experiments have been carried on during the past year with methods for in- 

 creasing the firmness of sliced Massachusetts-grown Mcintosh apples in order 

 to maintain their shape during canning, freezing, and baking. The use of cal- 

 cium as a firming agent is quite effective for this purpose. The amount of cal- 

 cium used (such as calcium chloride) and the time of the treatment will vary de- 

 pending upon such factors as the original firmness of the apples, the length of 

 time they have been in storage, the degree of firmness desired, etc. Concentra- 

 tions of from 0.03 to 1.50 percent calcium in the treating solution may be indi- 

 cated depending upon the processing method and the condition of the apples 

 These calcium treatment have been found to be just as effective with so-called, 

 "green Mcintosh" apples as with ordinary Mcintosh. 



Stability of Riboflavin in Processed Foods. (\V. B. Esselen, Jr., A. Filios ' 

 J. Crimmins, M. W. Paparella, and M. S. Gutowska.) An investigation of the 

 stability of riboflavin in a large number of commercially canned foods, packed 

 in glass or metal containers is being carried on. Many different kinds of baby 

 foods are included among the products considered. There appears to be consider- 

 able variation in the stability of riboflavin in different products, regardless of the 

 type of container in which they are packed. The loss of riboflavin during three 

 months' exposure to diffused daylight on a typical store shelf varied from 0.0 to 

 60.0 percent, depending upon the products. Such products as strained peas, 

 liver soup, chopped spinach, vegetables and liver, red kidney beans, chopped 

 prunes, strained and chopped beets, and chopped carrots showed only small 

 losses; while products such as strained green beans, custard pudding, tomato 

 juice, strained peaches, and strained tomato porridge showed greater losses. 

 These losses tended to increase during storage for 12 months. In some cases 

 losses, but not as great as those in samples exposed to the light, were found in 

 both glass and tin packed products stored in the dark and at different temper- 

 atures. 



To date the results show that in many glass-packed foods the loss of riboflavin 

 during storage on a store shelf under normal conditions would be small. The 

 results of the present investigation are in general agreement with an earlier 

 preliminary study made with glass and tin packed asparagus, peas, corn, and 

 green beans and show that riboflavin seems to be less stable in the more acid 

 products. 



Ascorbic Acids as Antioxidants. (C. R. Fellers, J. E. W. McConnell, J. J. 

 Powers, W. B. Esselen, Jr., L. R. Parkinson, and G. S. Congdon.) In 1940 this 

 department demonstrated that 1-ascorbic acid (vitamin C) was an effective 

 antioxidant in preventing surface darkening in home-canned fruits. As a result 

 of thi^ and later work carried on here and elsewhere, ascorbic acid is now recog- 

 nized as an important antioxidant in the food industries. Today it is being used 

 in such things as home-canned and frozen fruits, commercial frozen fruits, par- 

 ticularly peaches, apple juice, and certain beverages. 



During the past year a study has been made of the antioxidant properties of a 

 new ascorbic acid compound, 5, 6 diacetyl-1-ascorbic acid, which holds promise 

 of being adapted to use where a slower-acting antioxidant is indicated. The 

 rate of oxidation was found to be considerably slower than that of 1-ascorbic 

 acid or d-iso ascorbic acid during storage in a bottled buffered aqueous solution 

 at pH 4.0. On an equiv^alent weight basis the biological vitamin C activity of 

 5,6 diacetyl-1-ascorbic acid was comparable with that of 1-ascorbic acid as de- 

 termined by guinea pig bioassay. 



Further uses of ascorbic acid as antioxidants are being investigated. 



There is considerable interest at present in the fortification of such juices as 

 apple, cranberry, and grape with ascorbic acid to put them on a par with citrus 



