An investigation of factors affecting the composition of milk and of methods for the analysis of milk components : a thesis presented to Massey University in partial fulfilment of the requirements of the degree of Doctor of Philosophy, Massey University, Palmerston North, New Zealand

Abstract

Low solids-not-fat (S.N.F.) levels in the liquid Milk industry prompted an enquiry into the problem of meeting the minimum legal requirements for S.N.F. (8.5%) and into Methods for determining the S.N.F. content and the protein content of the milk. The methods, for determining the S.N.F., which were investigated were based mainly on the hydrometric or density technique which gives an indirect but rapid indication of the composition, whilst the amido black technique was examined with a view to assessing its suitability as a routine method for the protein determination. There is a growing awareness of the nutritional advantages of milk protein and of other nutritives in the solids-not-fat content of milk. Waite et al. have stated "In recent years the solids-not-fat content of milk has come to be regarded as of equal, or of greater importance, than the fat percentage. This change is the result of an increased awareness of the nutritive value of milk protein and other non-fatty constituents, in particular calcium and vitamins." Hansson in the same year wrote "The growing competition between fats of animal and plant origin has also led to the conclusion that the non-fat components of the milk will be emphasized more correctly in the future." Furthermore, it is considered that there is an urgent need to maintain milk composition up to the legal requirements when it is delivered to the consumer.