The fruiting bodies of shiitake mushrooms (Lentinula edodes) are highly susceptible to postharvest quality deterioration due to their loose tissue, high moisture, and active metabolism. Low-dose ultraviolet-C (UV-C) irradiation, a green, safe, low-cost, and efficient physical treatment especially suitable for high-moisture and metabolically active produce, offers a promising solution to this problem for the postharvest preservation of shiitake mushrooms. In this study, the effects of different doses of UV-C irradiation (2.5, 5.0, and 7.5 kJ·m⁻²) on the postharvest quality of shiitake mushrooms were systematically compared by measuring weight loss, respiration intensity, cap opening percentage, firmness, color (L*, a*, b*), electrolyte leakage, MDA content, antioxidant enzyme activities (SOD, CAT, POD, PAL), chitin content, chitinase activity, and the expression of LeCHI and LeCDA genes. The results showed that UV-C irradiation at 5 kJ m⁻² significantly delayed the increase in weight loss (by approximately 32% at day 15 compared to control) and reduced respiration rate (by 25–35% during days 3–9) and cap opening rate (27.3% vs. 48.0% in control at day 15) while maintaining higher firmness and better color retention over the control group. Furthermore, this treatment effectively inhibited electrolyte leakage and malondialdehyde accumulation, enhanced the activities of SOD, POD, CAT, and PAL, maintained chitin content, and downregulated the expression of chitinase and cell wall degradation-related genes. Thus, 5 kJ m⁻² UV-C irradiation is effective in maintaining postharvest quality and extending the storage time of shiitake mushrooms.

Rapid population growth has placed increasing pressure on global food systems. As a result, developing healthier and more sustainable food products has become an important research priority. In this context, edible fungi-based fermentation of cereal and legume substrates has attracted growing attention because it can enhance flavor, nutritional value, and bioactive potential through biotransformation. However, the dynamic quality changes of black bean during fungal solid-state fermentation (SSF) and its subsequent application in steamed bread remain insufficiently understood. This study investigated the effect of solid-state fermentation (SSF) using Ganoderma oregonense at different durations (12, 19, 26, 33, and 40 d) on the bioenhancement of nutritional and antioxidant activities in black bean. FTIR results showed that SSF of G. oregonense released active components mainly by destroying its dietary fiber structure. At 40 days of G. oregonense fermentation, the total dietary fiber content of black bean declined from 17.09 to 12.98 g/100 g, and the content of reducing sugars increased 5.20 times. G. oregonense is outstanding in optimizing protein and free amino acids, and the total amount of protein, γ-aminobutyric acid, essential amino acids, and free amino acids were enhanced by 24.07%, 35.25%, 68%, and 56.74%, respectively. In addition, the fermentation time had a significant effect (p < 0.05) on the antioxidant capacity of black bean, with a significant increase in the content of VE, total phenols, and total flavonoids, as well as the production of new antioxidant components. Steamed bread prepared using G. oregonense solidly fermented black bean flour (FBBF) shows better antioxidant activity and sensory acceptability than wheat steamed bread. The results suggest that FBBF has potential as a functional ingredient for value-added food applications.