ANNUAL REPORT, 1936 43 



was a greater accumulation of food material in the ceca than was the case in 

 the control group. Studies of intestinal flora showed no distinctive changes for 

 the whole milk, 1 percent, and 4 percent cocoa diets. The addition of 1 percent 

 cocoa to a straight milk diet had no significant effect on the fecal pH. 



Since the experiments in this study were conducted with laboratory animals 

 only, no direct application to human nutrition can be made. Assuming, how- 

 ever, that these results may have some application to human nutrition, we 

 may conclude that the cocoa in average commercial chocolate milk, which is a 

 trifle over 1 percent, does no harm nor does it enhance the nutritional value of 

 the milk. 



Vitamin G Content of Dairy Orange Beverages. (M. J. Mack, in co- 

 operation with C. R. Fellers, Horticultural Manufactures.) This project has 

 been completed during the past year and the results published in Food Research, 

 May-June 1936. The orange-flavored drinks, now being sold by many dairy- 

 men, were found to be relatively poor sources of Vitamin C. They contain on the 

 average only about 10 percent as much vitamin C as fresh orange juice, and 

 lose from 15 to 20 percent of their vitamin C during storage for 24 hours at 

 40° F. 



Sodium Alginate as a Stabilizer for Ice Cream. (M. J. Mack.) Since 

 the use of sodium alginate in ice cream is increasing, the product was compared 

 with gelatin, which is still the most widely used stabilizer for ice cream. Sodium 

 alginate, when properly incorporated in the mix, proved to be a satisfactory 

 stabilizer, producing mixes of relatively uniform viscosity which whipped readily 

 to the desired overrun during the freezing process. The finished ice cream was 

 smooth in texture and exhibited desirable melting characteristics. 



The use of sodium alginate as a stabilizer in ice cream is described in Con- 

 tribution 255 of the Massachusetts Agricultural Experiment Station which 

 appeared in the November 1936 issues of the Ice Cream Trade Journal and 

 Ice Cream Review. 



The Effect of Added Iodine on the Properties of Milk. (J. H. Frandsen, 

 W. S. Mueller, and Myer Glickstein.) Much work has been done on mineral 

 deficiencies in the human body, and the study of iodine in its various forms 

 has occupied the time of many investigators. The use of iodized milk is some- 

 times advocated in cases of iodine deficiency. If milk is to be iodized, it is of 

 course essential that there be no harmful effects on the properties of the milk. 



So far as work on the physical and chemical properties of milk has progressed, 

 there is no substantial indication that the heat and alcohol stability of the milk 

 are affected unless abnormally large amounts of tincture of iodine are added. 

 No differences in the creaming ability and viscosity were noted, and the whip- 

 ping ability of the cream from iodized milk seemed to be improved. Further 

 studies are in progress. 



Special attention has also been given to the effect of added iodine on the en- 

 zymes in milk. The work is still in progress, and the following results are ten- 

 tative only. The iodine had a paralyzing effect on the activities of the digestive 

 enzymes, both those added to milk and those normally found in milk. The 

 action of pepsin and trypsin was hindered by iodine up through 48 hours of 

 incubation; but after 72 hours, the paralyzing effect of iodine was not noticed. 

 Iodine retarded the activity of steapsin even after 72 hours of incubation. In 

 toluene-preserved samples, iodine at the rate of 50 p. p.m. had a slight activating 

 power on rennin, but beyond that concentration, iodine was toxic to rennin. 

 In non-preserved samples, there was a decline in the activity of rennin with 



