Abstract: In this study, we investigated the effects of the structural and functional properties of sheep milk whey and casein proteins under different thermal sterilization conditions. The common industrial sterilization conditions of 65 °C, 30 min, 80 °C, 30 s, 95 °C, 5 min and 135 °C, 4 s were selected to treat goat milk, and goat milk whey and casein proteins were isolated. Circular dichroism spectrometer, Fourier transform infrared spectrometer, fluorescence spectrophotometer, confocal laser microscope and atomic force microscope were used to analyze the changes of protein structure and properties. The results showed that the structural changes of whey and casein proteins treated at 65 ℃, 30 min and 80 ℃, 30 s were small, and the increase of protein unfolding and surface hydrophobicity (p ＜ 0.05) led to better foaming and emulsification properties of whey and casein proteins. The treatments at 95 °C, 5 min and 135 °C, 4 s resulted in a significant decrease in the α-helical structure content of the proteins, a significant increase in the content of the irregularly curled structure, a severe denaturation of the proteins, and a decrease in solubility and surface hydrophobicity (p < 0.05), which adversely affected the functional properties of goat's milk proteins as well as goat's milk stability. Based on the above studies, this paper reveals the changes of goat milk whey and casein proteins under different sterilization temperature conditions, which provides a reference for optimizing the quality and stability of goat milk products and helps to develop more functional goat milk products.

Key words: goat's milk, whey protein, casein, structural properties, functional features