Enhanced bioaccessibility of curcumin in Pickering emulsions stabilized by solid lipid particles

Abstract

To investigate curcumin release behavior of Pickering emulsions (PEs) with controlled crystal polymorphism, solid lipid particles (SLPs) were fabricated using Tween 40 (T40-SLPs) or sodium caseinate (SC-SLPs) at 4 °C or 25 °C. T40-SLPs were characterized as β crystal (100%) at 25 °C, and co-crystallization of Tween 40 (2 % by weight (wt.%) vs. 4 wt%) induced formation of β crystals (24.86% vs. 52.88%) at 4 °C. SC-SLPs solely contained α crystals at 4 °C, and addition of sodium caseinate (2 wt% vs. 4 wt%) reduced content of β crystals (7.55% vs. 2.82%) at 25 °C. The indigestibility of β crystals differentiated interfacial digestive behavior of SLPs. PEs stabilized by SC-SLPs underwent more aggregation and released more curcumin upon exposure to pepsin and mucin. High content of β crystals in SC-SLPs enhanced curcumin bioaccessibility in simulated intestinal digestion, whereas high SC concentrations induced undigested SC self-assembled with β crystals, reducing the curcumin bioaccessibility. PEs stabilized by T40-SLPs showed better-targeted delivery, with higher FFA release and curcumin bioaccessibility during in vitro intestinal digestion. Co-crystallization of T40 enriched β crystals in T40-SLPs but reduced the release and bioaccessibility of curcumin. Hence, surface modification of fat crystals and crystal structure determines bioaccessibility of curcumin in PEs stabilized by SLPs.