Studies on the Determination of Thermo-induced Viscosity Change Characteristics for Skimmed Milk Powder-Water Mixture System
In this paper the method for determination of the viscosity change of skimmed milk powder-water mixture system as temperature in a three-stage testing program of heating-temperature maintaining-cooling using a rapid viscosity analyzer.The denaturation degree of the milk powder induced by heat treatment during production and processing was evaluated by examining whether the peaks were present or not and viscosity of peaks in the curve,as well as the final viscosity at the end of operation.This article investigated the effects of the proportion of milk powder in the skimmed milk powder-water mixture system,the high or low holding temperature in the temperature program,and the length of holding time on the measurement results.The results indicated that the experimental conditions significantly affected the viscosity curve with temperature.In order to make the protein in the milk powder fully being gelled in the water,and ensure that the strength and viscosity of the gel were within a certain range,the most appropriate experimental conditions were as below:the proportion of milk powder was 44.5%(m/m),the holding temperature was 90℃,and the holding time was 5 minutes.Under this optimal condition,two batches of skimmed milk powder with two peaks and one peak in the viscosity curve were selected respectively.The thermotropic gel properties of the milk powder-water mixture system were measured every hour on the same day and every other day for seven consecutive days.The experimental results had good repeatability,and the relative standard deviation of each peak and the final viscosity were all less than 5%.
skimmed milk powderrapid viscosity analyzerthermo-induced viscosity changetemperature program
万方数据
维普
