High pressure processing combined with Phyllanthus emblica juice effectively inhibits enzymatic browning and enhances nutritional quality of NFC apple juice

This study investigated the combined effects of high-pressure processing and Phyllanthus emblica (PE) juice supplementation on enzymatic browning and nutritional quality of apple juice. All PE-treated groups delayed enzymatic browning. After 35 d, the 10% PE group showed a 0.17-fold higher L* value, and 1.27- and 0.29-fold lower a* and b* values, respectively. The HPP-PE treatment suppressed polyphenol oxidase (PPO) and peroxidase (POD), with 10% PE reducing initial PPO and POD activities by 28% and 24%, respectively, and remaining 23.81% and 26.25% lower by day 35. PE supplementation enhanced biofunctional activities. In the 10% PE group, total phenol and flavonoid contents increased by 13.5- and 3.78-fold on day 0, and by 28.75- and 6.4-fold on day 35, respectively. Correspondingly, ABTS and DPPH radical scavenging activities increased by 18.23- and 15.35-fold on day 0, and by 20.56- and 33.81-fold on day 35. Twenty phenols were identified in PE juice, predominantly ellagic acid, trigalloyl-hexoside, ellagic acid 4-O-β-D-glucoside, and geraniin. Molecular docking indicated that hydrogen bonding and ionic interactions were the key forces inhibiting PPO activity. By integrating high-resolution metabolite profiling with molecular docking, this study elucidated the structure–function relationships underlying PE-derived browning inhibition, offering a mechanistically grounded, clean-label strategy for NFC juice preservation.