Grape pomace (GP) is a major by-product from the wine industry, known for its bioactive compounds and their impact upon gastrointestinal (GI) health. However, bioaccessibility is often poor due to their degradation during digestion. This work aimed to encapsulate bioactive GP extract (GPE) into chitosan (CS) and alginate (Alg) nanoparticles (NPs) to mitigate degradation in the GI tract. Alg and CS NPs were optimized using a rotatable central composite design and NPs were characterized for their size, polydispersity, zeta potential and total phenolics (TP) association efficiency. The best formulations showed sizes ranging 523–853 nm, polydispersity indexes of 0.11–0.36, zeta potential of −15.0–14.9 mV and TP association efficiencies of 68 and 65%. FTIR confirmed that there was no formation of new chemical groups after association of the polymers with GPE. Both formulations improved the bioaccessibility of different phenolics following in vitro GI digestion, leading to increased antioxidant and antimicrobial activities.

Moreover, the permeability of bioactive compounds through a Caco-2/HT29-MTX co-culture was reduced, suggesting a higher residence time in the intestine. Cy5.5 was used for tracking the CS NPs, which did not affect the metabolic activity of Caco-2 and HT29-MTX cells. Confocal microscopy images confirmed the adsorption of NPs to the cellular layer and suggested a reduction of the tight junction protein occludin when cells were incubated with Cy5.5-CS in solution. This study suggests that encapsulation of GPE can offer protection against along the GI tract and improve its biological activity with significant impact for oral delivery applications, including functional foods.

葡萄渣（GP）是葡萄酒行业的主要副产品，以其生物活性化合物及其对胃肠（GI）健康的影响而闻名。然而，由于其在消化过程中的降解，生物可及性通常很差。这项工作旨在将生物活性GP提取物（GPE）封装到壳聚糖（CS）和藻酸盐（Alg）纳米颗粒（NPs）中，以减轻胃肠道中的降解。使用可旋转的中央复合材料设计优化了Alg和CS NP，并对NP的大小，多分散性，ζ电位和总酚（TP）缔合效率进行了表征。最佳配方的粒径范围为523–853 nm，多分散指数为0.11–0.36，ζ电位为-15.0–14.9 mV，TP缔合效率为68和65％。FTIR证实，聚合物与GPE缔合后没有形成新的化学基团。两种配方均改善了以下酚类化合物的生物利用度体外胃肠消化，导致抗氧化和抗菌活性增强。

此外，通过Caco-2 / HT29-MTX共培养的生物活性化合物的渗透性降低，表明在肠道中的停留时间更长。Cy5.5用于追踪CS NP，这不影响Caco-2和HT29-MTX细胞的代谢活性。共聚焦显微镜图像证实了NPs在细胞层上的吸附，并表明当将细胞与Cy5.5-CS一起在溶液中孵育时紧密连接蛋白occludin的减少。这项研究表明，GPE的封装可以提供针对胃肠道的保护作用，并改善其生物学活性，对口服给药应用（包括功能性食品）产生重大影响。