Several chemical analytical methods were applied to characterize the chemical structure of polysaccharides extracted from discarded apples and pomegranate peels using hydrodynamic cavitation methods in a circular economy perspective. In particular, the purity of the polysaccharides and the degrees of acetylation and methylation were evaluated by proton Nuclear Magnetic Resonance (¹H-NMR) analysis; simple sugars and galacturonic acid were analyzed simultaneously by High-Performance Anion Exchange Chromatography—Pulsed Amperometric Detector (HPAEC-PAD); the molecular weight of the extracted polysaccharides was determined by High-Performance Size Exclusion Chromatography-Refractive Index Detector (HPSEC-RID). The results showed a negligible presence of co-precipitated proteins/tannins, easily removed by dialysis, as well as other co-precipitated molecules such as monosaccharides and organic acids. Polysaccharides from apples consisted mainly of pectic material with a prevalence of homogalacturonans. Polysaccharides from pomegranate peels showed greater compositional variability with significant amounts of arabinose and galactose, a lower content of pectin, and the presence of rhamnogalacturonans I. Both polysaccharides were highly methylated and differed in the degree of acetylation, which could lead to different properties. Polysaccharides from apples presented two main molecular weights (>805 kDa and 348–805 kDa, respectively), while those from pomegranate peel showed a major fraction at 348 kDa and minor fractions < 23 kDa. In conclusion, the research tools proposed by this study have allowed defining the macrostructure of polysaccharides in a quick and efficient way to valorize these food by-products.

While a recent characterization of non-Saccharomyces thermally inactivated yeasts (TIYs) in a wine-like solution highlighted the release of oenologically relevant compounds and different oxygen consumption rates and antioxidant activity, here the impact of TIYs derived from Saccharomycodes ludwigii (SL), Metschnikowia pulcherrima (MP), Torulaspora delbrueckii (TD), and Saccharomyces cerevisiae (SC), as the reference strain, was evaluated in white wine. Wine treatment with TIYs resulted in an increase in polysaccharide concentration compared to the untreated wine, with SL-TIY exhibiting the highest release. Additionally, all TIYs, particularly SL-TIY, improved protein stability by reducing heat-induced haze formation. The addition of TIYs also demonstrated an effect on color parameters through phenolic compound adsorption, preventing potential browning phenomena. All TIYs significantly impacted the wine’s volatile profile. Overall, it was shown that an improvement in wine quality and stability may be obtained by using TIYs in the winemaking process.

Despite the widespread use of yeast derivatives (YDs) in winemaking, comparative studies on the impact of different inactivation technologies remain limited, especially when applied to non-conventional yeast species. To address this, the present study evaluated the impact of Saccharomycodes ludwigii (SL#64) derivatives, a non-conventional species characterized by a high cell wall polysaccharide content, produced via Thermal Inactivation (TI), High-Pressure Processing (HPP), and Partial Lysis combined with HPP (PL + HPP), on the polysaccharide content, colloidal stability, and sensory profiles of Garnacha Blanca and Tempranillo Blanco wines. A commercial Saccharomyces cerevisiae derivative was used as a reference yeast derivative. Polysaccharide concentration and colloidal stability were monitored at 2 and 15 days post-addition. All YDs significantly increased polysaccharide levels (3–21%), primarily within the first 48 h. HPP-treated SL#64-YDs proved the most effective in enhancing protein stability, reducing heat-induced turbidity by 21% after 15 days. SDS-PAGE analysis suggested that YD-derived polysaccharides acted as protective colloids, partially maintaining pathogenesis-related (PR) proteins in solution. In contrast, no significant improvement in tartaric stability was observed across treatments. Overall sensory evaluation, including quality, balance, aroma intensity, and Flash Profile characterization, revealed that YD treatments more clearly modified the sensory profile of the aromatically neutral Garnacha Blanca wines, whereas the greater aromatic complexity of the Tempranillo Blanco matrix partially masked these effects, although prolonged contact with TI and HPP reduced aroma intensity and perceived quality. These results suggest that HPP-derived yeast derivatives could be especially suitable for short contact applications, representing a promising non-thermal strategy for tailoring functional YDs to specific wine matrices.

Although phytosanitary treatments are necessary to protect grapes from parasitic diseases, consumers are increasingly concerned about the use of synthetic phytosanitary products and their possible residues in wine. Pre-harvest phytosanitary treatments are often inevitable, and consequently downtime is required to avoid possible residues on the grapes. Instead, natural phytosanitary products, such as essential oil (EO)-based products, can be applied close to the harvest without specific restrictions, with results that are not only technically convenient but also more attractive for the consumers. Because of the high antimicrobial activity of EO products, in the present study we evaluated the effect of different residual amounts of two new EO-based phytosanitary products on the alcoholic fermentation and the chemical composition of the final fermented products. In particular, two EO-based new formulations, exploitable in organic viticulture management, were evaluated. Increasing concentrations of each formulation were tested during laboratory scale fermentations and in comparison with synthetic and natural commercial phytosanitary products. Growth and fermentation kinetics of a commercial yeast strain of Saccharomyces cerevisiae and the chemical and sensory profiles of the final products were evaluated. Both new formulations showed no significant impact on the growth and fermentation kinetic of S. cerevisiae at any of the concentrations tested. In all trials, alcoholic fermentation was completed in 15 days. Instead, a different chemical composition of the final products was observed. Therefore, these new products might represent an interesting alternative tool to the conventional phytosanitary treatments, being applicable close to the harvest without negative impacts on the kinetics of alcoholic fermentation and also being more acceptable to wine consumers.