Heat-induced whey protein isolate gels improved by cellulose nanocrystals: Gelling properties and microstructure.

• Cellulose nanocrystals (CNC) strengthened heat-induced whey protein isolate gels. • CNC have good compatibility with protein matrixes at low concentrations. • Protein matrixes and CNC were combined by non-covalent interactions. • Active filling and enhanced cross-linking resulted in a stronger gel network. • CNC induced the formation of a stronger gel by concentrating protein matrixes. Cellulose nanocrystals (CNC) were successfully prepared from wheat bran, and their effects on the gelling properties and microstructure of heat-induced whey protein isolate (WPI) gels were investigated. The results showed that the water holding capacity, gel strength, viscoelasticity, and thermal stability of the composite gels were improved by increasing the CNC concentration from 0 to 1.0 % (w/v). The incorporation of CNC restricted water mobility and facilitated conformation conversion of the secondary structure from α-helix to β-sheet. CNC has good compatibility with the protein matrixes at relatively low concentrations. At higher CNC concentrations, the agglomerated CNC can serve as an active dehydrating agent to absorb moisture in the protein matrixes, which promotes unfolding and cross-linking of the protein molecules. Moreover, the active filling effects of CNC contributed to the formation of a compact and homogeneous gel structure. Therefore, naturally sourced CNC is suggested as a potential gel modifier in food industry. [ABSTRACT FROM AUTHOR]