Functional and gel properties of whey protein nanofibrils as influenced by partial substitution with cellulose nanocrystal and alginate

The influence of partial substitution of whey protein nanofibrils (WPNs) by alginate and cellulose nanocrystals (CNCs) on the properties of WPN solutions was investigated. Elemental and conductometry analyses indicated that CNC particles were sulphated. Partial substitution (17.5%) of WPNs with CNCs and alginate increased the consistency coefficient of WPN solutions by ≈ 1.3 and 4.6 fold, respectively. Alginate also increased the stability of a WPN foam by approximately 17 fold. WPN and WPN/CNC gels did not show syneresis, whereas the WPN/alginate gel had ≈27% syneresis. The fracture stress and strain of the WPN/alginate gel were nearly 9.9 and 3.3 fold higher than those of the WPN gel. Both CNC and alginate increased the porosity and pore size in the gel network. Infrared spectroscopy indicated that alginate crosslinked to WPNs through Ca2+ ions. CNC increased gel swelling under acidic conditions; alginate caused the gel to shrink.