Studies on the Activated Flavor of Milk

Abstract

Summary These studies indicate that heating milk to temperatures above 150° to 160° F. and cooling enhances the activated flavor of the subsequently unduly irradiated milk. When irradiation and homogenization are both used in processing milk better results are secured if irradiation precedes homogenization. Altering the “salt balance” of the milk by addition of various substances failed to increase or decrease the flavor intensity of the subsequently irradiated milk. Nitrogen and Avenex inhibited development of the flavor. It was found possible to remove the activated flavor from milk by oxidation. This was best accomplished by adding to the irradiated milk two to three parts per million of copper and then bubbling air through the milk at 140−145° F. The typical activated odor was produced by irradiation of aqueous solutions of egg white or of gelatin giving additional evidence that the protein fraction of milk is probably the parent substance of the flavor. The studies indicate that the activated flavor of milk unduly exposed to ultra-violet radiation is identical or practically identical with the burnt flavor which develops in milk exposed to sunlight. Evidence is given that if milk bottles can be devised which will eliminate all wave lengths of light less than 4600 A they will be effective in inhibiting development of the activated flavor caused by exposure of milk to sunlight.