Comparison of Physicochemical Properties of White Hypsizygus marmoreu Protein Extracted by Two Methods

The white Hypsizygus marmoreu has good flavor and nutrition, and is rich in protein. To fully develop the white Hypsizygus marmoreu protein resources, protein was extracted by traditional alkali method and ultrasonic assisted method. The protein’s physicochemical properties such as oil absorption, water holding, solubility, foamability, emulsification were analyzed. The results showed that ultrasound-assisted extraction increased the extraction rate of protein to 31.4%, which was 8% higher than the traditional alkaline method. Thermal experiments showed that the maximum weight loss rate of protein extracted by ultrasound was 311.4 ℃, and that of protein extracted by traditional alkali was 334.8 ℃. Fourier transform infrared analysis showed that the α-spiral structure decreased while the irregular curly structure increased for the protein extracted by traditional alkali method. Compared with the soybean protein isolate (SPI), at non neutral pH or the salt ion concentration of 0.5 mol/L, there was no significant difference for the emulsifying ability and stability between white Hypsizygus marmoreu protein and SPI. At the same pH, there was no significant difference in water retention and emulsification stability between the two extraction processes. At the same NaCl concentration, no significant difference was observed between the solubility, foam stability and emulsification stability. Within 25~65 ℃, the oil absorption and foaming stability of white Hypsizygus marmoreu protein showed no significant difference between that of SPI. In this range, the solubility and foamability of white Hypsizygus marmoreu protein increased firstly and then decreased with the change of temperature.