Diastase in Milk

Abstract

Béchamp in 1883 was the first to recognize the presence of diastase in human milk; at the same time in cow's milk he found no trace of this enzyme. 1 Bouchut 2 and Moro 3 , 4 , 5 confirmed the findings of Béchamp.

During the last decade a number of investigators have attempted to establish a quantitative diastase test as a means of detecting whether or not a milk had been pasteurized. Namely, diastase would be entirely or partly inactivated during pasteurization, the extent of its destruction depending on the temperature and the duration of heating. The methods used by these workers, while claiming to yield quantitative results, are quite crude in comparison to the qualitative methods of Béchamp and Bouchut. The more recent workers find diastase in the milk of practically all the mammals 6 examined and are able to determine diastatic activity in the presence of lead 7 , 8 , 9 and even mercury salts. 10 The latter fact is characteristic of the unreliability of these methods.

We approached the problem with analytical procedures, which in the instance of blood and urine proved to be adequate for the determination of very low as well as of high diastase values.

The method is in brief as follows: a 1.5% starch paste is prepared of pure commercial corn- or rice-starch (but not of soluble starch); 10 cc. of this starch paste and 4 cc. of a 1% NaCl solution are measured into a test tube, the mixture is warmed to 40°, and then 2 cc. of diluted milk are added. The extent of the dilution (usually 1:10 to 1:40) depends on a preliminary test, which is based upon the amyloclastic activity of the milk.