Grape pomace (GP), a major byproduct obtained from the winemaking process, is characterized by a high amount of phenolic compounds and secondary plant metabolites, with potential beneficial effects on human health. Therefore, GP is a source of bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory activity. As people are paying more attention to sustainability, in this work, we evaluate two different extractions (aqueous and hydroalcoholic) of GP bioactive compounds. In vitro simulated gastrointestinal digestion of the GP extracts was performed to improve the bioavailability and bioaccessibility of polyphenols. The antioxidant activity (ABTS and DPPH assays) and the phenolic characterization of the extracts by UHPLC-DAD were evaluated. The antimicrobial effects of GP antioxidants in combination with a probiotic (Lactiplantibacillus plantarum) on the growth of pathogenic microorganisms (Escherichia coli, Bacillus megaterium, and Listeria monocytogenes) were evaluated. As a result, an increase of antioxidant activity of aqueous GP extracts during the gastrointestinal digestion, and a contextual decrease of hydroalcoholic extracts, were detected. The main compounds assessed by UHPLC-DAD were anthocyanins, phenolic acids, flavonoids, and stilbenes. Despite lower antioxidant activity, due to the presence of antimicrobial active compounds, the aqueous extracts inhibited the growth of pathogens.

Grape pomace (GP)—the major by-product of winemaking processes—still contains bioactive molecules with known beneficial properties for human health, such as an antiradical scavenging activity or an antiproliferative activity of tumors. In vitro studies have demonstrated that GP polyphenols specifically influence colon cancer cell proliferation. In addition to previously published work, we tested the phenolic compounds of Aglianico GP following an in vitro simulated gastrointestinal digestion on colorectal cancer cell lines at different degrees of differentiation. Our experiments, using HT29 and SW480 cells, confirmed the anti-proliferative effect of GP gastrointestinal digested extract and provided intriguing insights on the way it influences the cancer cell features (i.e., viability, proliferation, and apoptosis). We observed that Aglianico GP extract showed a great ability to affect cell proliferation and apoptosis. Interestingly, both HT29 and SW480 cells produced a significant increase in Bax, and a significant increase in the Bax/Bcl-2 ratio and caspase-3. The gastrointestinal digested GP extract was previously characterized both for antioxidant activity and phenolic composition. As a result, the TPC and the antioxidant activity reached high values in the Aglianico GP digested extract, and the main compounds assessed by UHPLC-DAD were anthocyanins, phenolic acids, and flavonoids. This work shed light on the use of digested GP extract as a dietary ingredient, a very sustainable source of nutritional compounds with potential health benefits for colon cancer cell proliferation.

Stilbenes are a family of phenolic secondary metabolites that are known for their important roles in plant protection and human health. Numerous studies show that vine shoots, one of the most abundant winery wastes, could be used as a source of bioactive compounds such as stilbenes. The predominant stilbenoids in vine shoots are trans-resveratrol (Rsv) and ε-viniferin (Vf), whose content varies depending on numerous intrinsic and extrinsic factors. The present work investigates the influence of pre-treatment and variety on stilbene concentration in vine shoots. Vine shoots of the Primitivo and Negroamaro varieties were submitted to four different trials before stilbene extraction (untreated, dried at 50 °C for 24 h, dried at 70 °C for 15 min, and dried at 80 °C for 10 min). The results showed that the heat pre-treatments had a slight impact on the total phenol and stilbene content. In contrast, the variety variable had a stronger impact on stilbene concentration, ranging from 2700 to 6400 mg kg⁻¹ DW for untreated vine shoots of 23 Italian varieties. In all vine shoots, the most abundant stilbene compound was Rsv and the highest content was found in vine shoots of the Nero di Troia (5298.1 mg kg⁻¹ DW) and Negroamaro (5249.4 mg kg⁻¹ DW) varieties.

Ageing wine in barrels is an historical practice used to improve the aromatic complexity of wine, but due to the high cost and the long ageing period, alternative approaches have been developed, such as the use of wood chips and ultrasound treatment. The present paper reports the results of an investigation performed on wine (cv. Primitivo). Three treatments were investigated: a) control wine untreated; b) wine with toasted vine-shoot chips (10 g/L); c) wine with toasted vine-shoot chips (10 g/L) and treated by ultrasound. Wines were analysed after 7, 14, 21, and 28 days. The application of ultrasound combined with vine-shoot chips promoted tannin evolution, thereby accelerating the ageing process of wine. The chips addition decreased the total anthocyanins content and increased the stilbenes (trans-resveratrol and trans-piceid) and wood-related aromas (i.e., furfural, 5-methylfurfural) concentration. Finally, wines added with chips were richer in woody, vanilla, oak, and chocolate notes and more preferred by the tasters.

An ultrasound (US) treatment was applied during the vinification of three different red grape cultivars with the aim of assessing the impact on the volatile profile of the wines. A robust solid phase micro extraction coupled with gas chromatography mass-spectrometry (SPME-GC-MS) method was developed in order to fix the best parameters for optimizing the volatile organic compound (VOC) recovery. A 15% NaCl solution was added to the samples to increase the salting-out effect, the time/temperature were appropriately selected, and the matrix effect was evaluated by comparing synthetic and real matrices. In addition, external calibration curves were used to quantify the single volatile compounds. The analyses of the wine samples at 7 and 14 months of aging revealed that US exerted the highest effect on Aglianico, which had the highest amount of total VOC. US Nero di Troia showed similar results after 14 months of aging, while Primitivo was not affected by the treatment. Nevertheless, from discriminant analysis, a clear separation was observed between the control and ultrasound-treated wines for all three cultivars, with ethyl decanoate, ethyl isopentyl succinate, and butyric acid having the highest discriminant coefficients. In conclusion, the obtained results indicated that the effect of US treatment on the VOC profile of the wine considered in the experimentation is cultivar-dependent.