80 MASS. EXPERIMENT STATION BULLETIN 378 



the other hand, 5 percent of the total intake as canned dog food fails to 

 prevent this condition. 



Citrus By-products. (A. Sedky, C. R. Fellers, and W. H. Fitzpatrick.) 

 A new method of making marmalade has been developed in which the 

 orange peel is cooked separately. Retention of as much as 80 percent 

 of the ascorbic acid as well as better flavor and color is made possible by 

 use of this procedure. The time required for the preparation of marma- 

 lade may be greatly reduced if concentrated orange juice is used. 



Experimental packs of both canned grapefruit sections and juice show 

 that dextrose may successfully replace sucrose as a sweetening agent. 

 In bottled grapefruit juice, the loss of ascorbic acid was proportional to 

 the amount of oxygen present in the juice and container headspace. Thus, 

 deaeration of fruit juices and vacuumization of the filled container are 

 desirable in order to conserve the maximum amount of ascorbic acid in 

 the bottled juice. Flavor is likewise improved. 



Red Squill Research. (Cooperative with U. S. Fish and Wildlife Serv- 

 ice.) (A. S. Levine and J. A. Lubitz.) Three papers are in press bringing 

 up to date the publication of most of the red squill investigations. These 

 include reports on the toxicity of squill to various animals, the factors 

 affecting toxicity of red squill baits, and the relative values of several 

 volatile oils and imitation food essences as rat lures. 



Investigation has been completed to determine the optimum percentage 

 of red squill powder to be used in baits. The more toxic the squill, the 

 smaller the quantity required per bait. Thus, the more toxic squills are 

 the most efficient and therefore more economical although the initial cost 

 may be high at face value. 



In a comparison of type of baits, the rats ate corn meal-squill baits in 

 marked preference to poisoned baits made with meat or fish. 



Preservative Values of Organic Acids. (A. S. Levine.) Investigations 

 are being conducted to improve the preservation of soda fountain syrups 

 and fruit juices. The present practice of adding citric acid and sodium 

 benzoate is not entirely satisfactory. The substitution of acetic acid 

 (vinegar) for part of the citric acid may lead to better keeping qualities 

 without the need of sodium benzoate. Other organic acids are l)eing 

 studied and compared for their effect on the growth of yeast and molds. 



The availability of sodium glycollate medium for the cultivation of 

 anaerobes has made it possible to study the antiseptic effect of organic acids 

 on anaerobic bacteria by the same technique previously employed and 

 reported in similar studies with aerobic microorganisms. These results 

 are needed to develop the theoretical considerations of this project. 



Marine Products Research. (C. R. Fellers.) Efforts to can either 

 blue, sand, or rock crabs have always failed. As a result of many yt-ar^ 

 of study, a successful method for the canning of Atlantic crab meat has 

 now been perfected. The method consists essentially in stabilizing the 

 copper present in the hemocyanin of the crab's blood and flesh by means 

 of a protective brine dip containing small amounts of aluminum salts at 

 adjusted pH values. 



The canned meat of the blue crab contains about 18 percent of high- 

 quality protein; it is low in fat and high in ash. Particularly notable is 



