Hydrogen Sulfide Enhances Browning Repression and Quality Maintenance in Fresh-Cut Peaches via Modulating Phenolic and Amino Acids Metabolisms.

Effects of hydrogen sulfide (H2S) on the browning and quality maintenance of fresh-cut peach fruit were studied. The results showed that H2S treatment repressed the development of surface browning, suppressed the increase in respiration rate and weight loss, and delayed the decline of firmness while soluble solids content (SSC) and microbial growth were unaffected during storage. H2S treatment maintained higher contents of phenolic compounds, especially neo-chlorogenic acid, catechin, and quercetin, and delayed the degradation of phenolic compounds by enhancing the activities of phenolic biosynthesis-related enzymes and inhibiting the oxidative activities of polyphenol oxidase (PPO) in comparison with control. Moreover, H2S stimulated the accumulation of amino acids and their derivatives including proline, γ-aminobutyric acid (GABA), and polyamines (PAs) via enhancing biosynthesis and repressing degradation compared to control. These results suggested that H2S treatment enhanced the accumulation of phenolic, amino acids, and their derivatives by modulating phenolic and amino acids metabolisms, which contributed to the higher antioxidant activity and membrane integrity maintenance, ultimately repressing browning development and maintaining the quality. Therefore, the current study speculated that H2S might be a promising approach for browning inhibition and quality maintenance in fresh-cut peach fruit.

Hydrogen sulfide alleviates chilling injury in peach fruit by maintaining cell structure integrity via regulating endogenous H2S, antioxidant and cell wall metabolisms.

Effects of hydrogen sulfide (H2S) on chilling injury (CI), H2S, antioxidant and cell-wall metabolisms of refrigerated peaches treated with H2S and hypotaurine (HT, H2S scavenger) were investigated in present study. Results revealed that H2S treatment enhanced endogenous H2S content, which was associated with increased related H2S synthase enzymes activities, while HT showed the opposite results. Moreover, H2S treatment induced the accumulation of ascorbic acid, glutathione and the enhancement of antioxidant enzymes activities compared to control and HT, contributing to lower hydrogen peroxide content and superoxide radical production. Furthermore, H2S suppressed the increase of cell-wall degradation enzymes accompanied by higher levels of water-insoluble pectin, 24% KOH-soluble hemicellulose and cellulose, while HT accelerated these components degradation. Therefore, results indicated that H2S mitigated CI of refrigerated peaches by regulating H2S, antioxidant and cell-wall metabolisms, maintaining higher H2S and antioxidants contents, suppressing cell-wall degradation, thereby contributing to redox homeostasis maintenance and cell structure integrity.