Effect of Chlorine Dioxide Fumigation on Quality and Browning of Broad Beans

To study the effect of chlorine dioxide fumigation on the preservation of postharvest broad beans, broad beans were fumigated with different concentrations of ClO₂ (0, 15, 30 and 60 μL/L), stored at room temperature and evaluated for color difference, firmness, mass loss percentage, browning index and decay index after 0, 2, 4, 6 and 8 days. The results showed that compared to the control group, ClO₂, at all concentrations tested, could inhibit the increase in mass loss percentage, browning index and decay index, and delay the decline in firmness, especially at a concentration of 30 μL/L. Furthermore, 30 μL/L ClO₂ fumigation significantly reduced the respiratory intensity, inhibited chlorophyll degradation and malondialdehyde accumulation in broad beans during the 8-day storage period, suppressed the increase in superoxide anion generation rate and the accumulation of hydrogen peroxide, and maintained higher activities of superoxide dismutase (SOD) and catalase (CAT), suggesting that ClO₂ fumigation could alleviate oxidative damage to the cell membrane. In addition, ClO₂ treatment repressed the activities of polyphenol oxidase (PPO) and peroxidase (POD), maintained the activity of phenylalanine aminolyase (PAL) and the content of total phenols, and delayed the occurrence of browning. Moreover, ClO₂ treatment increased the contents of vitamin C, soluble protein and starch, and inhibited the increase of the reducing sugar content in broad beans (P < 0.05), thus maintaining better quality of broad beans. In conclusion, 30 μL/L ClO₂ fumigation effectively maintained the edible value of broad beans and improved the storage quality while enhancing the antioxidant capacity.