Stability and Digestion Properties of Curcumin-loaded Emulsion Gels Fabricated by Oat β-Glucan and Proanthocyanidins

In this paper, the curcumin-loaded O/W emulsion gels with an oil phase fraction of 80% were fabricated using oat β-glucan (BG) and proanthocyanidins (PA) complexes to improve the stability and bioaccessibility of curcumin. The microstructure and formation mechanism of BG and PA self-assembly complexes were analyzed. Additionally, the microstructure, rheological properties, stability, and in vitro digestive properties of curcumin-loaded emulsion gels fabricated with different mass ratios of BG/PA (BG/PA=1:0~1:1.0) were explored. The results showed that BG-PA could self-assemble to form colloidal complexes through hydrogen bonding and hydrophobic interactions. Meanwhile, colloidal complexes that were approximately spherical in shape could be formed when the mass ratio of BG to PA was 1:0.5. The curcumin-loaded emulsion gels could not be obtained with merely 2% BG (BG/PA=1:0), but the BG-PA complexes could form a stable emulsion gel. In particular, curcumin-loaded emulsion gels fabricated by BG-PA complexes with BG/PA=1:0.1~1:0.5 had small particle sizes (15 μm) and good centrifugal stability (instability index<0.3). Additionally, when emulsions were exposed to high temperatures (55 ℃) and UV light, BG-PA based emulsion gels effectively slowed down the degradation of curcumin in a dose-dependent manner. The results of simulated gastrointestinal digestion showed that the bioaccessibility of curcumin in the BG-PA based emulsion gels was higher compared with the emulsion fabricated by 2% BG alone (P<0.05). The research results can serve as a technical reference for the application of plant-based polysaccharide and polyphenol complex systems in gelled food and cosmetic emulsions loaded with bioactive ingredients.