Effect of Glabridin on Enzymatic Browning of Fresh-Cut Potatoes

To elucidate the impact of glabridin on browning in fresh-cut potatoes, the effect of treatment with 100 μmol/L glabridin on the color quality of potato slices was examined. The inhibitory mechanism of glabridin on browning in potatoes was revealed through physicochemical analysis and non-targeted metabolomics. The results showed that glabridin delayed enzymatic browning of fresh-cut potatoes for 2 days. By chelating copper ions from the active center of polyphenol oxidase (PPO), glabridin down-regulated its activity by 10.03%–14.82%, reducing total phenolic utilization; the final total phenolic level was 82.29 mg/g higher and the soluble quinone level was 8.60%–21.91% lower in the treatment group than in the control group. Glabridin enhanced the activities of peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), with the most pronounced effect being on POD and CAT, which were increased by 13.80%–37.13% and 36.92%–139.55%, respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity in fresh-cut potatoes treated with glabridin increased by 11.63%–41.88% compared with the control group, while hydrogen peroxide levels were only 17.35%–93.75% of the control group. Glabridin inhibited the rise in relative electrolytic leakage, and reduced final relative conductivity by 114.33 μS/cm and the content of malondialdehyde (MDA) by 12.95%–22.93% compared with the control group. Non-targeted metabolomics analysis showed that glabridin induced significant changes in 96 metabolites (57 upregulated and 39 downregulated) during potato browning, mainly enriched in secondary metabolism, purine and pyrimidine metabolism, ABC transporter, phenylalanine synthesis. Together, glabridin inhibits browning of fresh-cut potatoes by regulating phenolic metabolism, antioxidant capacity, cell membrane integrity and the accumulation of key metabolites, which provides theoretical support for the application of natural glabridin to control enzymatic browning of potatoes.