Inhibition of maltol on enzymatic browning in potato: Combined effects on PPO activity, substrate biosynthesis, and...

Enzymatic browning poses a major challenge for fresh-cut potatoes. In this study, maltol, which is naturally present in ginseng, was used as a browning inhibitor to suppress the browning of potatoes. The results indicated that 1 g L^-1 maltol prolonged the shelf life of fresh-cut potatoes from day 2 to day 8 and contributed to maintaining the volatile flavor profile. Further research found that maltol mainly inhibited browning through three pathways. Firstly, maltol inhibited polyphenol oxidase (PPO) by directly binding to PPO, chelating the Cu²⁺ in the active center and regulating amino acid metabolism. Secondly, maltol inhibited phenylalanine ammonia-lyase activity and thereby suppressed the synthesis of the key substrate chlorogenic acid. Thirdly, it enhanced the activity of superoxide dismutase and catalase in the early stage of treatment, maintaining a low level of oxidative stress. These pathways collectively contribute to browning inhibition, providing a viable solution for fresh-cut potatoes preservation.