Protein aggregation occurs in biological systems and industrial processes, affecting protein solubility and functional properties. In this study, whey protein isolate (WPI) obtained from bovine milk was used as a model to study the dependence of aggregation on pre-heating temperature and on protein and calcium concentrations. WPI solutions (0.1-5.0%, w/v) were heated at 25-85°C for 30min prior to cooling and calcium addition. Tryptophan shifted to a more hydrophilic environment as WPI concentrations and pre-heating temperatures increased. Pre-heated WPI solutions yielded soluble particles, which aggregated to form porous gel-like particles by addition of calcium chloride. WPI microgel particles could be prepared by using a cold gelation method and preheated the protein above 65°C. The particle size was monodisperse with sizes of about 190nm and 255nm, respectively in solutions pre-heated to 75 or 85°C and containing 5m. m calcium.
Ni, Y., Wen, L., Wang, L., Dang, Y., Zhou, P., & Liang, L. (2015). Effect of temperature, calcium and protein concentration on aggregation of whey protein isolate: Formation of gel-like micro-particles. International Dairy Journal, 51, 8–15. https://doi.org/10.1016/j.idairyj.2015.07.003