Diffusion kinetics of vitamin B6 released from bicontinuous and phase-inverted gelatin-agarose co-gels using blending-law modelling

Abstract

In this study, gelatin and agarose were used as the phase-separated biopolymer system and vitamin B6 served as the diffusant. FTIR analysis confirmed the absence of any chemical interactions between gelatin, agarose, and vitamin B6 under the experimental conditions of this investigation. XRD analysis validated that vitamin B6 was homogenously dissolved in the composite low-solid system. Polarised light microscopy provided insights into the mixture topology and tangible evidence of the formation of bicontinuous and phase-inverted gelatin-agarose composite gels. Small-deformation dynamic oscillation was performed to establish theoretical blending law modelling, which predicted the phase volume and effective concentration of individual components (gelatin and agarose) in their respective domains. Then, a diffusion study was conducted and a novel blending law for diffusion was proposed to estimate the theoretical diffusion coefficient of vitamin B6 in the composite gel by utilizing the effective concentration of each polymer in their phase. Outcomes were compared positively to the observed diffusion coefficient from UV–vis analysis. Results demonstrate that blending-law diffusion theory can be utilised to ascertain the molecular transport of hydrophilic vitamins released from aqueous biopolymer composites.