Structural and colloidal properties of whey protein aggregates produced by indirect tubular heating and direct steam injection

This research aimed to compare the structural and colloidal properties of whey protein aggregates (WPA) produced by indirect tubular heating and direct steam injection methods. The results illustrated that WPA produced from direct steam injection had better colloidal stability and functionality compared to those produced by indirect heating. WPA obtained from direct steam injection had smaller sizes and higher surface hydrophobicity, although they had a similar surface negative charge. More importantly, WPA from direct steam injection had much better colloidal stability. Especially for the sample produced by the direct steam injection containing a higher concentration of 30 %, which remained stable during 20 days’ storage. In comparison, precipitation was noticed after ten days for the sample with a lower concentration of 10 %, indicating the functionality and colloidal stability of WPA were also affected by the protein concentration. Those results demonstrated that the functionality of WPA can be tailored by selecting appropriate materials and manufacturing techniques.