Studies on the Source-Origin of Activated Flavor in Milk

Abstract

Milk unduly exposed to radiation, either natural or artificial, will acquire a flavor defect called activated, sunshine, or burnt. This defect is to be differentiated from that referred to as oxidized fiavor. Homogenized milk is known to acquire the flavor more readily than unhomogenized milk. Excessive or improper exposure of milk to artificial radiation is a frequent cause for occurrence of the flavor. The ultimate prevention of the development of the flavor, however, necessitates further information concerning its origin and method of development. In the study presented here, milk or milk products, and other substances were exposed for prolonged periods to radiation so as to accentuate the intensity of the flavor, and permit its ready identification and isolation. Reviews of the literature on the activated flavor of milk have been included in previous reports (4, 8). I t was pointed out that the flavor originates with the protein fraction of milk, and it was indicated that the flavor which results from undue exposure to ultra-violet radiation is identical or very similar to the burnt or sunshine flavor caused by exposure of milk to sunlight. Radiation is known to cause destructive effects upon proteins in general and to produce disagreeable flavors and odors. Casein and lactalbumin have been shown to develop the typical activated flavor of milk. The present study is concerned with ascertaining the specific source of the flavor.