Effects of hydrogen sulfide on the surface whitening and physiological responses of fresh-cut carrots

BACKGROUND: The effect of hydrogen sulfide (H2S) on the inhibition of the surface whitening of fresh-cut carrots was investigated. Whitening index; H2O2 and malondialdehyde (MDA) contents; activities of catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD); and antioxidant capacities were evaluated. RESULTS: H2S treatment significantly inhibited the surface whitening of fresh-cut carrots (P < 0.05), reduced the accumulation of H2O2 and MDA, and enhanced antioxidant enzymes (CAT, APX and GR) activities and antioxidant capacities (P < 0.05). The PAL, PPO and POD activities of fresh-cut carrots were inhibited by treatment with H2S (P < 0.05). Furthermore, correlation analysis revealed that whitening index was significantly positively correlated with H2O2 content, lipid peroxidation, PPO and POD activities. CONCLUSION: H2S inhibited the surface whitening of fresh-cut carrots by reducing H2O2 accumulation and lipid peroxidation, and also inhibited PPO and POD activities. (C) 2018 Society of Chemical Industry