An improved method for measurement of the syneresis of curd formed by rennet action on milk

Abstract

SummaryIn this method, the curd, formed in a beaker, was retained after cutting by means of a wire grid placed on top of it. This enabled the whey to be poured off easily at timed intervals for measurement of its volume. The method gave results reproducible within 1·5%. Increasing the amount of rennet added to the milk increased the rate of syneresis of the curd slightly. Adding CaCl2 to the milk, raising the temperature and decreasing the pH, all increased the rate of syneresis. Addition of fat, as cream, to skim-milk decreased the rate of syneresis proportionally. The rate of syneresis was decreased if the milk was concentrated by ultrafiltration and increased if the milk was diluted with permeate. In all instances the early stages of syneresis followed first-order kinetics, the rate depending on the amount of whey remaining within the curd. The later stages of syneresis appeared to depend on hydrophobic forces. Probably, the increasing aggregation of the casein within the curd caused the whey to be squeezed out.