The natural product 3-Mercaptopropionic acid is a highly effective browning inhibitor by directly capturing polyphenol oxidase activity

Abstract

Polyphenol oxidase (PPO) is a key enzyme responsible for enzymatic browning, which significantly affects the quality and marketability of fresh-cut fruits and vegetables. 3-Mercaptopropionic acid (3-MPA) has been identified as a promising natural compound with potential anti-browning properties. This study investigated the efficacy of 3-MPA as an anti-browning agent for fresh-cut potatoes and tobacco leaf pulp. Various concentrations of 3-MPA were evaluated, with 50 mg/L identified as the optimal treatment level for inhibiting enzymatic browning while maintaining sensory quality. 3-MPA treatment enhanced antioxidant capacity, reduced PPO activity, and mitigated quinone formation in potato samples. Molecular docking simulations and dynamics analyses revealed that 3-MPA competitively binds to PPO's active site, forming a stable enzyme-inhibitor complex that effectively blocks substrate access. The inhibitory mechanism involves both direct enzyme interaction and pH reduction. 3-MPA demonstrated superior potency to conventional anti-browning agents, requiring lower concentrations for comparable effects. These findings provide insights into 3-MPA's molecular mechanism of action and establish its potential as a promising anti-browning additive for food preservation applications.