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Research on thermal characteristics of whey powder, milk replacer and lactose

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Paper number  131622139,  2013 Kansas City, Missouri, July 21 - July 24, 2013. (doi: @2013
Authors:   Lin Zhao, Hongying Wang, Dandan Kong, Rui Gao, Jie Yang
Keywords:   Thermal characteristics Whey powder milk replacer lactose feed processing

Abstract. In order to study the stability of feed ingredients during conditioning, the heat-sensitive material of sucking pig feed was chosen for this research. The specific heat of six kinds of whey powder, a milk replacer and lactose from 25℃ to 100℃ was measured by using differential scanning calorimeter (DSC). And the thermal conductivity and thermal diffusivity of the eight kinds of samples from 30℃ to 80℃ was measured by a KD2 Pro thermal properties analyzer.

The result was that the specific heat of eight materials increased with increasing temperature. The cubic regression model about the specific heat on temperature of each sample was got though the SPSS. The R2 of the regression equations were above 0.970 except the milk replacer’s 0.875. The fitting effects were good. Moisture content significantly affected the specific heat of whey powder, and the composition of whey powder affected the shape of regression model. The thermal conductivity of most different materials at the same temperature had no significant difference, while the thermal conductivity of different moisture had significant difference mostly. The thermal diffusivity of different materials at the same temperature had significant difference. Moisture and whey protein content significantly affected the thermal diffusivity. The microstructure of the eight materials at different temperature was observed by a scanning electron microscope (SEM). It had been found that the particles of whey powder and milk replacer were conglomerated at high temperature, which explained why the thermal conductivity of the materials was positively correlated with temperature.

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