Liposomes loading grape seed extract: A nanotechnological solution to reduce wine-making waste and obtain health-promoting products

Liposomes with grape marc seed extract were developed as a promising solution to reuse the wine industry's waste and develop nanotechnological products with high added value for human health. Thus, a hydroalcoholic extract rich in phenolic compounds, such as flavan-3-ols and proanthocyanidins, was obtained from seeds isolated from the bagasse of the cultivar Merlot. This extract was nanoincorporated in liposomal vesicles, which reached a size of 238.6 nm, polydispersity index of 0.252, the zeta potential of -14.66 mV, pH 5.71, and catechin content of 0.75%. The liposomes remained stable for 30 days under refrigeration. Corona protein formation was not found when vesicles were added to the culture media, due to the fact that they did not change the physico-chemical properties in the culture media. The liposomes were viable in human fibroblasts (HFF-1). They were also capable of neutralizing the basal production of reactive oxygen species (ROS), which are produced during the normal cell metabolism and cell culture procedures, not being cytotoxic to the cells, demonstrating antioxidant potential. The analytical method for the quantification of catechins was shown to be linear (r= 0.9994), precise (RSD < 4.0), and specific to determine the catechin without the interference of the constituents from liposomes. It has been proved that the incorporation of polyphenols contained in grape seeds, resulting from vinification residues, in liposomal vesicles are effective, as they improve the stability and bioavailability of these compounds and can be used as a promising technological solution to obtain beneficial products, such as new food ingredients and sustainable packaging, taking advantage of the wine industry's waste.