Whey proteins solubility as function of temperature and pH

An integrated study was conducted on the effects of temperature and pH on the solubility of whey proteins. The solubility was determined experimentally in the range of 40-60°C for temperature and 3.5-7.8 for pH. The results showed that, both temperature and pH influenced in the protein solubility, and these properties had great interaction. Besides, for whey proteins, the solubility values were minimum at the pH value of 4.5, which is the isoelectric point of whey proteins, for all temperature values. It was also observed that at pH 4.5, the solubility decreased as the temperature increased, which indicated that the protein denaturation occurred. This behavior was also noticed in the neutrality (pH=6.8).