Tóm tắt

Grape pomace (GP) is a major by-product from the wine industry, known for its bioactive compounds and their rnimpact upon gastrointestinal (GI) health. However, bioaccessibility is often poor due to their degradation during rndigestion. This work aimed to encapsulate bioactive GP extract (GPE) into chitosan (CS) and alginate (Alg) rnnanoparticles (NPs) to mitigate degradation in the GI tract. Alg and CS NPs were optimized using a rotatable rncentral composite design and NPs were characterized for their size, polydispersity, zeta potential and total rnphenolics (TP) association efficiency. The best formulations showed sizes ranging 523–853 nm, polydispersity rnindexes of 0.11–0.36, zeta potential of −15.0–14.9 mV and TP association efficiencies of 68 and 65%. FTIR rnconfirmed that there was no formation of new chemical groups after association of the polymers with GPE. Both rnformulations improved the bioaccessibility of different phenolics following in vitro GI digestion, leading to in-creased antioxidant and antimicrobial activities. rnMoreover, the permeability of bioactive compounds through a Caco-2/HT29-MTX co-culture was reduced, rnsuggesting a higher residence time in the intestine. Cy5.5 was used for tracking the CS NPs, which did not affect rnthe metabolic activity of Caco-2 and HT29-MTX cells. Confocal microscopy images confirmed the adsorption of rnNPs to the cellular layer and suggested a reduction of the tight junction protein occludin when cells were rnincubated with Cy5.5-CS in solution. This study suggests that encapsulation of GPE can offer protection against rnalong the GI tract and improve its biological activity with significant impact for oral delivery applications, rnincluding functional foods.