151. The reactions and properties of annatto as a cheese colour, with particular reference to the chemistry of cheese discoloration

Abstract

The properties of commercial annatto solutions have been examined from the point of view of the cheese-making process. (1) The effect of initial colour strength, p H of the medium and distribution during manufacture are recorded. (2) Methods are described for the extraction of the annatto colour from milk products. (3) The effects of old annatto solutions, metallic impurities (copper and iron) and sulphydryl are shown. (4) It is suggested that the mechanism underlying the development of “bleached” and “pink” discoloration in cheese is an oxidation process, and the effect of oxidation on annatto solutions has been studied in some detail. (5) Suggested standards for annatto extracts for use as cheese colours are appended.