Enhancing the valorization of fruit processing by-products is pivotal for advancing the industry. Black mulberry wine residues, a by-product, contains some bioactive compounds, yet its antioxidant and anticancer potentials remain unverified. In this study, ultrasound-assisted enzymatic extraction was optimized by response surface methodology to obtain the flavonoids extracts from black mulberry wine residues, whose antioxidant capacity and anti-cancer activity in vitro was investigated. The results showed that under the optimal extraction conditions (enzyme ratio at pectinase:cellulose = 2:1, mixed enzyme concentration 0.31 mg/mL, enzymatic hydrolysis temperature 55.35 °C, enzymatic hydrolysis time 79.03 min, and ultrasonic time 22.71 min), the extracts from black mulberry wine residues (BMWR-E) reached 5.672 mg/g. At a concentration of 1.2 mg/mL, BMWR-E exhibited strong DPPH and hydroxyl radical scavenging activities. At a concentration of 2.5 mg/mL, BMWR-E showed a strong superoxide anion radical scavenging capacity, with no significant distinction compared to the positive control group (Vitamin C) (p > 0.05). Cell viability assay results showed that BMWR-E was non-toxic to normal BRL-3A cells when applied at concentrations of 0.1–0.3 mg/mL for an incubation period of 24 h, but BMWR-E exhibited the ability to inhibit the proliferation of HepG2 cells. At concentrations of 0.2 mg/mL and above, BMWR-E could induce late apoptosis of HepG2 cells by increasing the protein expression levels of Bax, caspase-3, and caspase-12, reducing the protein expression levels of Bcl-2, inducing cell cycle arrest at G0/G1 phase, thereby inhibiting the proliferation of HepG2 cells. The bioactive properties make BMWR-E possess potential in developing new antioxidants and anti-cancer agents, which would significantly enhance the economic worth of agricultural by-products in product processing. This research can improve the utilization rate of agricultural product processing by-products and protect the environment.

Chinese bayberry residue (CBR) is a by-product of processing, which can be used as an auxiliary material during the processing of quinoa rice wine. In this study, the effects of CBR on the chemical profile, bioactive function, taste traits, and flavor of Chinese quinoa rice wine (CQRW) were investigated. The results showed that adding CBR increased the total phenolics, the total flavonoids, and antioxidant capacity. Malic acid content was the highest in Chinese rice wine (CRW), while the total content of components detected in HPLC-MS/MS was the highest in 10%CBR + CQRW. The CQRW exhibited the highest amino acid content, followed by 20%CBR + CQRW. E-tongue analysis results showed that 10%CBR + CQRW, 20%CBR + CQRW, and CQRW had the closest taste traits. Moreover, GC-MS analysis identified 72 aroma compounds in 10%CBR + CQRW sample, more than other samples. In summary, adding 10% CBR significantly improved the quality of CQRW.

Three yeast strains isolated from fig fruits (Candida humilis DBXD1, Torulaspora delbrueckii S14, and Saccharomyces cerevisiae S2–7) were evaluated for their potential to enhance the aromatic complexity of fig wines. Enzyme activity assays demonstrated that C. humilis DBXD1 exhibited maximum β-glucosidase activity (2.94 ± 0.13 U/mg prot) and T. delbrueckii S14 showed the highest esterase activity (0.94 ± 0.06 U/mg prot). Sequential inoculation of these non-Saccharomyces strains with S. cerevisiae S2–7 increased contents of key aroma compounds in fig wines, including ethyl acetate, isoamyl acetate, hexyl acetate, butanoic acid esters, isoamyl alcohol, nonanal, 2-nonanone, and α-terpineol. Metabolic pathway analysis identified valine, leucine and isoleucine degradation, glycine and serine metabolism, and the glucose-alanine cycle as the primary differential pathways contributing to flavor enhancement. These findings demonstrated that sequential inoculation with indigenous high enzyme-producing yeasts provides a practical foundation for industrial production of fig wines with distinctive aromatic characteristics.