Non-invasive acidic pretreatments using acetic acid (1–5 mM) and citric acid (0.02–0.1 g g⁻¹ TS) were investigated to enhance anaerobic digestion (AD) of waste-activated sludge (WAS). Both pretreatments improved short-term process stability, with pH (6.5–7.1) and alkalinity (1000–5000 mg CaCO₃ L⁻¹) remaining within optimal ranges during 10-day digestion. Acetic acid markedly enhanced solubilization and acidification, increasing volatile fatty acids to ~2500 mg L⁻¹ (+67% vs. control), whereas citric acid achieved ~2000 mg L⁻¹ (+37%). EPS analysis revealed pronounced redistribution of polysaccharides and proteins, with acetic acid inducing stronger disruption of the EPS matrix (SB-EPS polysaccharides up to 34.1 mg eq Glc mL⁻¹). Specific methane yield increased from 28.5 mL CH₄ g⁻¹ VS (control) to 101.7 mL CH₄ g⁻¹ VS with acetic acid (3.6-fold) and to 73.8 mL CH₄ g⁻¹ VS with citric acid (2.5-fold). Gompertz modeling confirmed higher maximum methane potential, ~68% higher maximum methane production rates, and reduced lag phases for both pretreatments. In contrast, pharmaceutical concentrations (31 compounds) were largely unaffected by acid pretreatment, with significant reductions observed only for selected biodegradable molecules.

Orange wine, a traditional Georgian winemaker’s product, has recently received outstanding global interest from both winemakers and wine lovers. Orange wines are made from white grape varieties through prolonged contact of the skin and seeds in the fermentation process, which is actually a technique for producing red wines. It is well known that wine polyphenols have certain biological activity and, therefore, can contribute to the health benefits of moderate (red) wine consumption. But, data on chemical composition and bioactivity of orange wines are scarce. Thus, we collected 24 Serbian orange wines present at a market in 2022. The analyses of seven phenolic acids, six flavonoids, two stilbenes, fifteen anthocyanin glucosides, galactosides and arabinosides using HPLC-UV/VIS techniques was applied to elucidate differences in samples’ polyphenolic profiles. α-Amylase, α-glucosidase and lipase in vitro inhibition activities were evaluated using spectrophotometry. The most abundant polyphenols in the examined samples were gallic acid (0–49.5 mg/L), caffeic acid (0–22.2 mg/L) and catechin (0–76.7 mg/L). Piceid was detected in some samples (0.1–0.3 mg/L), while only five samples had a sporadic, low content of several anthocyanins. Principal component analyses (PCA) showed grouping of most of the samples in the central part, while sample 19 (produced in a north-Serbian winery) was obviously distinguished, mostly due to its highest content of gallic acid and catechin. The discriminating power was lower than 1.0 for all polyphenols. The analyzed orange wines had considerable hypoglycemic potential: activity ranged from 0.2 to 5.9 and 0.1 to 433 mg acarbose eq/mL of wine for α-amylase and α-glucosidase, respectively. Lipase inhibition was also notable: 7–43 ng orlistat eq/mL of wine. Direct correlation between expressed activity and determined polyphenols was not found, but PCA revealed samples 10, 16, 18 and 24 as the wines with the most prominent digestive-enzymes-inhibition activity. The presented results are just a part of our intensive research on the bioactivity of orange wines. Overall, our results should elucidate the possibility of health benefits of moderate consumption of orange wines, but also to contribute, at least partially, to the increase in recognition of Serbian orange wines in the domestic and global market.

Orange wine is a wine obtained via the vinification of white grapes in a similar way to making red wine, so the fermenting juice spends time macerating in contact with the grape skins, affecting the color and structure of the final wine. Sulfur dioxide (SO₂) is the primary preservative used in wine. At wine pH, the most abundant forms are molecular SO₂, responsible for the antioxidant and antimicrobial effects, and bisulfite. This study was conducted to determine the levels of total SO₂ in orange wines marketed in Serbia and to assess the risk of SO₂ exposure through wines. Twenty-four orange wines were subjected to the volumetric analysis of total SO₂. Health risks were assessed taking into account wine consumption regarding the population average, for regular drinkers only and chronic heavy drinkers, according to the World Health Organization data, as well as the Serbian Food Consumption Survey. The content of total SO₂ varied from 10.8 to 79.4 mg/kg, and there were no products exceeding 200 mg/kg, which is the regulated level in Serbia. A risk assessment was conducted according to the position of the European Food Safety Authority that the available toxicity database was inadequate to derive a group acceptable daily intake (the previous temporary ADI was 70 mg SO₂ equivalents/kg bw per day) and that a margin of exposure (MOE) approach should be used instead. The MOE was calculated as the ratio of a lower confidence limit of the benchmark dose of 38 mg SO₂ equivalents/kg bw per day, which was based on prolonged visual evoked potential latency, and used to estimate the exposure of men, women and both sexes. The resulting MOEs, evaluated by applying an assessment factor of 80, indicated no risk concern in any of the exposure scenarios. Minimum MOE values were obtained for males in the consumers-only scenario (1061 and 357 for the mean and high (last quartile mean) exposure levels, respectively). Although encouraging, the findings of this study should be interpreted considering that SO₂ could be used in various food products and that only an aggregate exposure (accounting for all exposure sources) could fully reveal the associated health risks.

Background/Objectives: Vitis vinifera is a rich source of polyphenolic compounds that are known for their benefits on skin health, including antioxidant, anti-inflammatory, and photoprotective effects. Red wines have shown a positive impact on cardiovascular disease, diabetes, and cancer prevention; however, evidence regarding their effects on skin biology remains scarce. This study evaluated red wine concentrates obtained from Cabernet Sauvignon and Merlot varieties, selected based on their previously demonstrated biological activities, to identify the samples with the highest potential for skin health applications by assessing their inhibitory activity against skin-related enzymes (tyrosinase, elastase, and collagenase), along with their effects on HaCaT cells, including cytotoxic, antioxidant, anti-inflammatory, and wound healing activities. Methods: Enzyme inhibition studies were based on spectrophotometric methods; the MTT and CV assays were carried out to test the cytotoxicity, and the DCFH-DA assay was employed to evaluate the antioxidant activity of the wine concentrates; wound healing potential was examined by the cell scratch assay, and anti-inflammatory activity was investigated using ELISA and qPCR analyses. PCA of the samples and their biological activity was performed as well. Results: Examined red wine concentrates exhibited significant enzyme inhibitory activity and showed no cytotoxicity on HaCaT cells up to the concentration of 50 μg/mL; the samples stimulated cell migration, inhibited intracellular ROS production in AAPH-stressed keratinocytes, and selectively modulated TNF-α-induced inflammatory responses, reducing IL-8 secretion while enhancing certain cytokine transcripts, underscoring the complexity of their bioactive effects. Conclusions: Red wine concentrates showed significant potential as skin-beneficial agents, demonstrating strong antiaging, marked cellular antioxidant effects and wound healing activity when applied at non-cytotoxic concentrations. Multivariate analysis revealed distinct bioactivity profiles among the wine concentrates.