Enhancing the antifungal and antioxidant activity of Agaricus bisporus extract using gamma radiation: implications for shelf-life extension of fresh-cut apples

Abstract

Fresh-cut fruits are highly perishable due to enzymatic browning and microbial spoilage following tissue disruption. This study investigated whether γ-irradiation of the edible mushroom Agaricus bisporus enhances its antioxidant and antifungal properties and whether the treated extract can be applied as a natural preservative for fresh-cut apples. Ethanolic extracts of A. bisporus were irradiated at 0-8.0 kGy and evaluated against six apple-spoiling fungi (Penicillium expansum, P. chrysogenum, Botrytis cinerea, Fusarium oxysporum, Aspergillus flavus, and A. niger). Among the tested solvents, ethanol yielded the most potent extract, showing a 14-mm inhibition zone against P. chrysogenum. Irradiation at 6.0 kGy significantly increased total phenolic content (3.25 mg GAE g⁻¹) and DPPH scavenging activity (46.3% at 100 µg mL⁻¹) (p < 0.05). The 6.0 kGy extract inhibited fungal enzymes-protease (40%), cellulase (35%), and lipase (45%)-and caused hyphal deformation, as observed by SEM. Sorbitol protection assays indicated cell-wall targeting. GC-MS profiling revealed irradiation-induced modifications in the fatty acid and sterol compositions. When applied at 10% (w/v) to fresh-cut apples stored at 4 °C for 10 days, the irradiated extract reduced browning, retained firmness, and decreased fungal and bacterial counts by 1.3 and 1.6 log CFU g⁻¹, respectively. Overall, mild γ-irradiation (6.0 kGy) enhanced the bioactivity and preservative potential of A. bisporus extract, supporting its application as a natural, clean-label agent for fresh-cut produce preservation.