Modulating the 3D printability of vitamin D3-nanoemulsion-based dairy gels: Influence of emulsifier on gel structure, printing behaviour and vitamin D3 retention

Abstract

This study investigates the effect of two protein emulsifiers (whey protein isolate-WPI and sodium caseinate-NaCas) at two concentrations (0.5 & 1% w/w) on the rheology, gel structure, thermal stability, 3D printability, vitamin D3 (cholecalciferol) encapsulation and retention to formulate vitamin D3-nanoemulsion-based dairy gels. Results demonstrated that the vitamin D3-nanoemulsion-based dairy gels stabilized with protein emulsifiers (NaCas and WPI) exhibited superior viscoelasticity and 3D printability as compared to control. FTIR spectra, SEM, and XRD patterns revealed enhanced inter and intra molecular crosslinking promoted by the emulsifiers that led to a robust gel. NaCas further strengthened the protein-protein interactions as compared to WPI, hence vitamin D3-nanoemulsion-based dairy gel stabilized with 1% NaCas exhibited the highest storage modulus (G') (19,580 Pa), maximum thermal degradation temperature (376 °C), and recorded the highest encapsulation efficiency (94.1%) and retention (377.2 IU/g) of vitamin D3 (cholecalciferol) attributed to the lowest droplet size (124.85 nm) and PDI (0.24), highest zeta potential (-44.85 mV) and stability (TSI = 0.2) of nanoemulsion.