Vitis vinifera L., commonly known as grapes, is one of the most widely cultivated crops worldwide, with over 80% used for wine production. However, the winemaking process generates substantial residues, including grape pomace (GP), wine lees, and wastewater, which can pose significant environmental and economic challenges. Among these, GP stands out not only as a waste product but also as a rich source of polyphenols—bioactive compounds with recognized antioxidant and anti-inflammatory properties. Recent advancements have expanded the application of GP-derived extracts, particularly in the health and food industries, due to their potent bioactive properties. This review provides a comprehensive overview of the valorization of GP, focusing on its phenolic composition and therapeutic potential. It evokes innovative, environmentally friendly extraction techniques and integrated methods for the chemical analysis of these valuable compounds. Additionally, the health benefits of GP polyphenols are explored, with recent experimental findings examining their metabolism and highlighting the key role of gut microbiota in these processes. These insights contribute to a deeper understanding of the biological activity of GP extracts and underscore their growing significance as a high-added-value product. By illustrating how winemaking by-products can be transformed into natural therapeutic agents, this review emphasizes the importance of sustainable development and eco-friendly waste management practices, significantly contributing to the advancement of a circular economy.

Global warming is directly linked to a lower concentration in organic acids in grape berries, leading to higher pHs in wine. Because of this lack of acidity, many important factors are impacted, as wine acidity and pH play a crucial role in various equilibriums. Indeed, the lower acidity and the higher pH modify the parameters of wine, such as free and molecular sulfur dioxide availability, colour and sensory aspects. Therefore, it is an ongoing challenge for winemakers to deal with wine acidification and thus preserve wine physico-chemical properties and prevent early spoilage due to microbiological instability induced by high pH. Different acidification methods are allowed by the OIV, chemical acidification being one the most common, followed by physical acidification and microbiological acidification. This review examines these three methods of acidification. The first part details chemical acidification and gives a complete description of various organic acids used in winemaking, and their different properties and regulations; the second part focuses on physical acidification, such as cation exchange resins and electrodialysis; and the last part briefly reviews the novelty of microbiological acidification in wine.

Nowadays, grape berries mature earlier due to climate change. Higher sugar contents are observed, whereas lower ones in organic acids, leading to increased pH values. Those biochemical changes have direct consequences on the balance and quality of wines made from such grapes. Chemical acidification, commonly used to compensate for the lack of acidity in musts or wines, includes tartaric, malic, lactic, and citric acids. Fumaric acid (FA), naturally present in the grape berries at low concentrations and already authorized in the member states of the OIV to inhibit malolactic fermentation in wines, seems to be a promising alternative to those acids to lower the pH. However, the evolution of FA levels added at bottling and its impact on wine quality during its conservation have not yet been studied. Therefore, the aim of the present study was to develop and validate a simple method using liquid chromatography coupled with a diode array detector, which can be used routinely for the determination of the added fumaric acid in wines. The proposed and validated method uses a ProntoSIL C-18 analytical column and an isocratic elution with water acidified at 0.1% formic acid. The run time, including column cleaning with acetonitrile and re-equilibration, was 40 minutes.

In this study, the reactivity of procyanidins and anthocyanins in young and aged Prokupac wines toward salivary proteins is investigated via SDS-PAGE and UHPLC-QTOF-MS to determine the differences between the phenolic compounds of red wine in relation to the aging process of wine. SDS-PAGE analysis revealed that procyanidins, flavanol-anthocyanin polymers, and ellagitannins in aged wine have strong affinities for salivary proteins, leading to the formation of insoluble complexes. By contrast, young wine contained predominantly procyanidins with high salivary protein affinity, as well as monomeric flavan-3-ols and anthocyanins, which mainly form soluble aggregates, while polymeric phenolics were less represented. Electrophoretic patterns further showed that seed-derived procyanidins mainly formed insoluble complexes with salivary proteins, whereas skin-derived anthocyanins tended to form soluble ones. The total content of all phenolic compounds quantified by UHPLC-QTOF-MS was 2.5 times higher in young wine than in aged wine, primarily due to the significantly greater abundance of malvidine-3-O-glucoside in young wine (eightfold higher level in young wine). Targeted UHPLC-QTOF-MS analysis of selected phenolics confirmed the electrophoretic results and showed a higher binding affinity of procyanidins in aged wine compared to young wine, as well as a higher percentage of procyanidin binding compared to anthocyanins, independent of the age of the wine. Sensory evaluation showed that aged wine had higher tannin quality scores, whereas young wine exhibited greater acidity and astringency, with bitterness being comparable between them. These results highlight the influence of wine aging on the interaction between phenolic compounds and salivary proteins and emphasize the dominant role of procyanidins in protein binding and the potential synergistic contribution of anthocyanins to mouthfeel perception.