Effect of pH-responsive pectin-Carboxymethyl cellulose sodium composite polysaccharide-Camellia oleifera oil hydrogel beads on in vitro intestinal lipid digestion.

Camellia oleifera oil, a traditional Asian edible oil, exhibits gastroprotective and anti-inflammatory effects. Its abundant long-chain fatty acids (oleic and linoleic acids) inhibit pro-inflammatory cytokine release and reduce intestinal oxidative stress, benefiting colon health. However, digestion of Camellia oleifera oil in the stomach and small intestine may promote its absorption in the upper gastrointestinal tract, thereby reducing its potential benefits for colon health. Therefore, in this study, an oil-in-water (O/W) emulsion system was formulated consisting of an aqueous phase containing pectin and sodium carboxymethylcellulose (CMCNa) and an oily phase consisting of Camellia oleifera oil at a concentration of 5-25 % (w/w). The combination of pectin, which has strong emulsifying properties, and sodium carboxymethylcellulose, which has low emulsifying ability alone, enhances the densification of the network and thus improves stability. The hydrogel beads were designed to retain and protect the camellia oil under upper gastrointestinal tract (GIT) conditions, followed by release in the colon. The emulsion was most stable at a complex polysaccharide pH of 3.5 and a water-to-oil ratio (w/w) of 35:15. The oil-in-water emulsion was dropped into ferric chloride solution to form stable hydrogel beads by ionic cross-linking with 99 % ± 0.36 % encapsulation efficiency and 39 % ± 0.65 % loading capacity. The results of in vitro digestion modeling showed that these hydrogel beads remained intact in gastric fluid (pH 1.2) and gradually released Camellia oleifera oil into the intestinal fluid (pH 6.8) with a controlled release rate of 13.80 %. These results highlight the potential for targeted delivery and functional food development.