Enhanced in vitro bioavailability of resveratrol-loaded emulsion stabilized by β-lactoglobulin-catechin with excellent antioxidant activity

The study aimed to fabricate beta-Lactoglobulin-catechin (beta-La-Ca) conjugates as a natural designed antioxidant emulsifier to improve the physicochemical stability of resveratrol emulsion delivery system. Fourier transform infrared (FT-IR) and fluorescence spectroscopy analysis confirmed the formation of conjugates using free radical grafting. The antioxidant ability of emulsion was evaluated by DPPH scavenging activities and ORAC experiments. The emulsion stabilized by beta-La-Ca conjugates exhibited strong antioxidant activity with ORAC value of 2541.39 +/- 29.58 mu mol TE/g, which was significantly higher than that by beta-Lactoglobulin alone with 387.96 +/- 23.45 mu mol TE/g or their mixture with 948.23 +/- 32.77 mu mol TE/g. During the whole simulated gastrointestinal digestion, emulsion stabilized by beta-La-Ca conjugates exhibited excellent oxidative stability that the lipid was mainly digested in the small intestine. This behavior attributed to the greater stability of resveratrol to chemical transformation leading to a higher overall bioavailability in vivo. These results suggested that the beta-La-Ca conjugates could be used to fabricate the emulsion-based delivery system to improve the oxidative stability and bioavailability of chemically labile hydrophobic bioactive compounds.