Mechanism of H₂S in Inhibiting the Senescence and Browning of Fresh-Cut Potatoes

The market for fresh-cut fruits and vegetables is gradually expanding and is popular among consumers, but fresh-cut fruits and vegetables are highly susceptible to browning, causing a decrease in their quality and nutrition. Although anti-browning reagents and cryopreservation methods are often used for fresh-cut fruits and vegetables, the effects are not satisfactory. In this paper, hydrogen sulfide (H₂S) donor NaHS solution was used for fumigation of fresh-cut potatoes to explore the mechanism of H₂S signaling on the browning of fresh-cut potatoes at the biochemical level. Fresh-cut potatoes were fumigated with H₂S and it was found that H₂S treatment maintained better color compared with the browning of water control. Then, total phenolic content, reactive oxygen species-related metabolites hydrogen peroxide (H₂O₂) and superoxide anion (·O₂^-), along with malondialdehyde (MDA), the activities of antioxidant enzymes, and the browning-related enzymes polyphenol oxidase (PPO), catalase (CAT), peroxidase (POD), and phenylalanine amine lyase (PAL) were determined. The results of both principal component analysis (PCA) and correlation analyses consistently indicated that CAT activity showed a strong positive correlation with the browning degree of fresh-cut potatoes. The data indicated that H₂S reduced the degree of browning, increased the total phenolic content, inhibited the accumulation of reactive oxygen species (ROS) content, inhibited POD, PPO, and PAL activities, and increased CAT activity.