Steviol glycosides improve the textural properties of whey protein gel

Steviol glycosides (SGs) have been used as non-nutritive sweeteners widely in various food matrixes. In this experiment, SGs including natural SGs and a synthetic glucosyl steviol glycoside were found to be capable to modulate heat-induced gelation of whey protein isolate (WPI), improved the gel properties such as rheological, water holding capacity, textural, thermal stability and microstructural properties. Within the SGs concentration up to 1.0 wt%, enhancement on the textural properties of WPI was concentration-dependent. With 1 wt% of assayed SGs, the storage modulus, loss modulus, gel strength of SG-WPI gel were up to 11.2-fold, 4.6-fold, 5.2-fold of that of the gels free of SGs, respectively. The frequency sweep indicated that the SGs could also attenuate the frequency dependence of WPI gel in a concentration-dependent manner. The ability of the SGs to improve the gelation properties of WPI followed the same sequence of their surface activity and interaction energy: Rubusoside similar to Monoglucosyl rebaudioside A > Stevioside > Rebaudioside A.