A green extract rich in oleanolic acid obtained from Aglianico red grape pomace as a promising anti-browning agent

Enzymatic browning has deleterious implications in food industry. In musts, especially in white ones, this phenomenon driven by polyphenol oxidases threatens wine quality and stability. Herein, an oleanolic acid (OA)-enriched extract from Aglianico red grape pomace obtained by the green solvent dimethylcarbonate was investigated as an alternative anti-browning agent. The extract inhibited tyrosinase with an IC₅₀ of 83.84 ± 7.42 μg/mL. When added to Fiano di Avellino musts (0.01-5.0 mg/mL), it reduced browning, as demonstrated by CIELAB colorimetry, with effective stabilization at values ≥0.08 mg/mL. LC-MS/MS analyses highlighted preservation of caftaric acid, catechin, and epicatechin. These data, along with sustained levels of grape reaction product in treated samples, indicated reduced oxidative degradation. Principal component and correlation analyses confirmed a concentration-dependent protective effect against must browning. These findings highlight the potential of OA-enriched extracts as natural, sustainable alternatives to sulphur dioxide for limiting enzymatic browning.