Fabrication of phenolic loaded spray-dried nanoliposomes stabilized by chitosan and whey protein: Digestive stability, transepithelial transport and bioactivity retention of phenolics.

Low bioavailability of phenolic compounds (phenolics) results in low in vivo bioactivity, thus their co-encapsulation could enhance potential health benefits. In this study, reconstitutable nanoliposomes loaded with phenolics varying in solubility were fabricated using spray drying after stabilized by chitosan (CH) or whey protein (WP). The physicochemical properties, biocompatibility, digestive fate, and bioactivity retention of phenolics in different forms were investigated. The surface charge of nanoliposomes (NL) shifted from -18.7 mV to positive due to conjugation with cationic CH (53.1 mV) and WP (14 mV) after spray drying while it was -26.6 mV for only spray-dried phenolics (SDP). Encapsulation efficiency of the tested phenolics ranged between 64.7 % and 95.1 %. Simulated gastrointestinal digestion/Caco-2 cell model was used to estimate the digestive fate of the phenolics yielding up to 3-fold higher bioaccessibility for encapsulated phenolics compared to their native form, combined or individually. However, the cellular uptake or transepithelial transport of phenolics did not differ significantly among formulations, except trans-resveratrol in WP-NL. On the contrary, the suppressive effect of phenolics on fatty acid induced hepatocellular lipid accumulation was strongly dependent on the encapsulation method, no activity was retained by SDP. These findings suggested that reconstitutable nanoliposomes can improve the absorption of phenolics by facilitating their bioaccessibility and thermal and/or processing stability during spray drying.