Abstract:
Objective: This study systematically investigated the efficient extraction process of purple yam anthocyanins, a gelatin/carrageenan composite-hydrogel delivery system was constructed, and the stability and biosafety in gastrointestinal digestion environments were elucidated. Methods: Anthocyanins were extracted using acidic ethanol method. The apparent viscosity, gel strength, and encapsulation efficiency of gelatin-carrageenan composite-hydrogels (ratio 8:2, w/w) at different concentrations were characterized by a rheometer and texture analyzer. The digestion models in vitro were used to evaluate the stability and swelling properties of anthocyanins in gastric fluid (pH3.0, 2 h) and intestinal fluid (pH6.8, 6 h), and the effect of the hydrogel on IEC-6 cell proliferation was assessed using the CCK-8 assay. Results: Acidic ethanol-assisted extraction achieved an anthocyanin yield of 57.20 mg/g, which was significantly higher than that of the conventional maceration method (
P<0.05). The 0.5% composite hydrogel, composed of a gelatin–gellan gum wall material at a mass ratio of 8:2 and encapsulating anthocyanins, exhibited the most favorable performance. The gel strength, apparent viscosity, and encapsulation efficiency were 21.4 g, 0.09 Pa·s, and 90.81%, respectively. The anthocyanin hydrogel formed a stable three-dimensional network structure across a wide range of angular frequencies, effectively ensuring anthocyanin encapsulation. Storage stability tests showed that anthocyanin degradation was significantly lower at 4 ℃ than at 37 ℃, and the hydrogel exhibited good stability at high temperatures. SEM images revealed that the anthocyanin composite-hydrogel formed a typical three-dimensional porous network structure, with pore sizes primarily ranging from 50 to 200 μm.
In vitro digestion experiments further confirmed that the hydrogel effectively delayed anthocyanin degradation and promoted its sustained release in the small intestine. The CCK-8 assay demonstrated that the composite-hydrogel exhibited minimal cytotoxicity (
P>0.05), confirming its high biosafety. Conclusion: The gelatin/carrageenan composite hydrogel significantly enhances the gastrointestinal stability and targeted delivery efficiency of purple potato anthocyanins, providing a theoretical basis for its application in functional food development. Future studies should verify its bioavailability enhancement effect through
in vivo experiments.