Molecular transport of vitamin B6 from whey protein and agarose composite gels using diffusion blending law modelling

In this investigation, whey protein and agarose were employed as the phase-separated biopolymer system, with vitamin B6 acting as the diffusant. Fourier-transform infrared (FTIR) spectroscopy affirmed the absence of chemical interactions among all constituents within the experimental parameters. X-ray diffraction (XRD) analysis corroborated the uniform dissolution of vitamin B6 within the composite low-solid mixtures. Confocal scanning laser microscopy elucidated the topology of the matrix, providing tangible evidence of the phase-separated whey protein-agarose networks. Small-deformation dynamic oscillation in-shear was employed to establish a rheological blending law model, predicting the phase volume and effective concentration of the individual components (whey protein and agarose) within their respective domains. Subsequently, a diffusion study was conducted, advocating a novel blending law for molecular transport to estimate the theoretical diffusion coefficient of vitamin B6 in the composite gel by leveraging the effective concentration of each polymer within its phase. The outcomes were positively compared to the observed diffusion coefficient of the vitamin from the composite gel using UV–vis spectroscopy. These results underscore the viability of the blending-law diffusion theory in elucidating the molecular transport of hydrophilic vitamins released from aqueous biopolymer composite gels.