Lycium barbarum leaf polysaccharide Pickering emulsion for curcumin delivery: Interactions between curcumin and polysaccharides at the oil-water interface

The use of polysaccharide Pickering emulsions for delivering bioactive compounds has attracted significant attention recently. However, the destabilizing effects of bioactive compounds on these emulsions remain largely unexplored, limiting the development of high-performance delivery systems. This study investigates how curcumin loading affects the stability and delivery performance of Lycium barbarum leaf polysaccharide Pickering emulsions. Curcumin loading significantly destabilizes these emulsions, reducing stability indices of mineral-containing emulsions from 92.3 %–94.8 % (unloaded) to 31.7 %–90.7 % (loaded), and demineralized emulsions from 96.4 %–97.6 % (unloaded) to 0 % (loaded). Mechanistic studies reveal that curcumin interacts with polysaccharides at the oil-water interface through hydrogen bonds and hydrophobic interactions, forming large (556.42–652.38 nm), highly wettable (contact angle θ o/w of 49.3°-63.8°) composite particles that disrupt the emulsion network. Simulated digestion studies show that demineralized emulsions have higher free fatty acid release rates (71.6 %–74.9 %) and lower curcumin bioaccessibility (33.5 %–34.2 %), compared to mineral-containing emulsions with rates of 44.2 %–62.5 % and bioaccessibility of 36.8 %–41.3 %. This research provides critical insights for improving food emulsion applications.