Mechanistic insights into inulin-fatty acid conjugates as β-carotene carriers for enhancing stability

To mitigate the low stability of β-carotene (βC), this study developed amphiphilic inulin (INU)-fatty acid (FA) conjugates by hydrophobically modifying INU with stearic acid, oleic acid (OA), linoleic acid, and linolenic acid, which were subsequently employed for βC encapsulation.

Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance verified successful synthesis, with critical micelle concentrations ranging from 0.014 to 0.035 mg mL^-1. Among all the βC-INU-FA micelles, βC-INU-OA showed the strongest stability and homogeneity, with its encapsulation efficiency and loading capacity for βC reaching 62.26% and 0.251 mg mg^-1, respectively. It also showed good stability at 4 and 25 °C. Co-assembly molecular dynamics (MD) simulations confirmed that INU-OA could encapsulate βC molecules by the strong van der Waals force provided by OA, resulting in stronger stability compared with unmodified INU. This superior performance of INU-OA was attributed to its cis-double-bond-induced bent conformation, which promoted a porous structure and enhanced hydrophobic interactions with βC, as evidenced by scanning electron microscopy and MD simulations.

This study combines macroscopic and microscopic analyses to demonstrate the potential of INU-OA-βC micelles as a promising βC delivery system, providing new insights for amphiphilic polysaccharide-based carrier design. © 2026 Society of Chemical Industry.