30 MASS. EXPERIMENT STATION BULLETIN 374 



V. EFFECT OF ADDED IODINE ON THE ENZYMES OF 

 MILK AND ON OTHER ENZYMES 



By Myer Glickstein, W. S. Mueller, and J. H. Frandsen 

 Department of Dairy Industry 



It is recognized that the heating of milk, as in pasteurization, tends to 

 destroy its biological properties (enzymes and vitamins) as well as the 

 bacteria present. From time to time methods have been advocated in 

 which chemical treatment is substituted for pasteurization in the effort to 

 control milk-borne bacteria without injuring these biological properties. 

 Buddeization, which employs hydrogen peroxide, is an example. It was 

 suggested by Goldthwaiti that iodine added to milk would control the 

 bacteria and at the same time enhance the nutritive properties of the milk. 

 The study here reported was undertaken to determine the effects of added 

 iodine, both organic and inorganic, on some enzymes that occur naturally 

 in milk and on certain enzymes of the intestinal tracts of man and animals. 



The possible importance of natural milk enzymes may be suggested 

 by the following citations from the literature: Lane-Claypon (1) sug- 

 gested that the enzymes are beneficial in infant feeding; Cohen and Ruelle 

 (2) recorded observations showing the beneficial effects of unheated milk 

 for children and suggested that certain enzymes of the milk may be re- 

 sponsible for the effects; Waksman and Davidson (3) advanced the opin- 

 ion that the enzymes may act as therapeutic agents in the treatment of 

 certain diseases. 



It is possible that the addition of iodine and related compounds to milk 

 may have detrimental effects on the enzymes of the digestive tracts of 

 consumers. Clifford (4) reported that the digestion of fish protein by 

 trypsin was delayed by halogen salts of lithium, sodium, and ammonium; 

 Steppuhn and Timofejewa (5) reported that, at pH 3.8, iodine decreased 

 the activity of pepsin; Waksman and Davidson (3) stated that lipase and 

 ptyalin were injured by iodine; according to Haldane (6), all enzyme 

 activity is retarded by iodine; Gerber (7) found that the caseification of 

 milk by enzymes was delayed in the presence of increasing amounts of 

 iodine, and that iodine inhibited the digestion of starch by both vegetable 

 and animal enzymes. 



EXPERIMENT.-XL 



All milk samples were obtained daily from the fresh milk supply from 

 the college farm. The raw milk samples were taken in clean bottles and 

 immediately iodized and shaken thoroughly. The pasteurized samples 

 were taken immediately after the completion of the process in the college 

 plant and were promptly iodized. There has been some controversy as 

 to the form of iodine, organic or inorganic, that is best utilized by the 

 body when taken internally. Accordingly it was decided to employ both 

 forms of iodine in the present studies. The organic iodine used was a 

 patented product secured from the Iodine Products Company of New 

 York, and the inorganic icKline was tincture of iodine made to conform 

 to U. S. P. standard. 



'Minutes of a conference on nutrition. Massachaisetts State College, December 4, 193S. 



