Heat-Treated Whey Powder Solutions as Natural Antibrowning Agents in Fresh-Cut Potatoes

Enzymatic browning severely limits the quality and marketability of fresh-cut potatoes. This study investigated the antibrowning potential of whey powder solutions (WPS) subjected to different heat treatments (20°C, 50°C, 70°C, and 90°C) and their effects on enzymatic activity, oxidative status, and nutritional quality during refrigerated storage. Among the treatments, WPS heated at 50°C (WPS 50) was the most effective in delaying browning development. WPS 50 significantly reduced polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities, resulting in lower accumulation of chlorogenic acid, the main PPO substrate. In addition, WPS 50 maintained higher L* values and reduced total color difference (TCD) by up to 48% compared to the control. The treatment also limited hydrogen peroxide accumulation and preserved ascorbic acid content throughout storage. Correlation analysis revealed strong associations between PPO activity, oxidative markers, phenolic metabolism, and color deterioration. The improved antibrowning performance of WPS 50 could be related to heat-induced structural changes in whey components, particularly, changes in sulfhydryl group availability and pH characteristics. Overall, these findings highlight that moderate heat treatment (50°C) optimizes the functional properties of WPS, enabling effective suppression of enzymatic browning through coordinated regulation of enzymatic activity, oxidative status, and phenolic metabolism. Heat-treated WPS therefore represent a promising natural alternative to conventional anti-browning agents for fresh-cut potato processing.