Effect of pH and Heat-Induced on the Yak Β-Lactoglobulin Denaturation and Aggregation

The effect of pH and heating temperature on yak (β-Lactoglobulin) β-Lg denaturation/aggregation was investigated. Temperature and pH significantly influenced the rate and content of yak β-Lg denaturation/aggregation and the protein formation in solution. The content of native β-Lg monomer decreased with increase in temperature at all pH range. β-Lg was heated above 80°C the content of native β-Lg monomer at pH 4.5-5.5 was reduced markedly than higher pH range from 6.5 to 8.5. Meanwhile the formations and content of yak β-Lg solution were complication at pH from 6.5 to 8.5 after heated 80°C and 90°C. The trend of hydrodynamic diameter and particle size was similar. The particle size in yak β-Lg solution increased markedly form (52 and 75 nm) pH 8.5 to (345 and 489 nm) pH 4.5 when β-Lg was heated at 80°C and 90°C, respectively. pH and heating temperature are important parameters that can influence the heat-induced denaturation/aggregation and the characteristic of yak β-Lg and yak whey proteins. And these researches provide some basis date and results to better understanding the mechanism of yak β-Lg denaturation, disulphide-linked aggregation and precipitation.