Ultra-high pressure-assisted enzymatic extraction enhances phenolic release and functional potency in fermented dark tea extracts.

This study aimed to enhance the extraction efficiency of tea polyphenols from dark tea using ultra-high pressure-assisted enzymatic extraction (UHPAEE). Extraction conditions were optimized by single-factor experiments and Box-Behnken design. Under the optimal conditions, the polyphenol content reached 77.23 ± 0.98 mg/g. Compared with UHPAEE, the polyphenol contents obtained by ethanol extraction and ultra-high pressure extraction were 44.81% and 25.73% lower, respectively. Untargeted metabolomics profiling detected 2788 metabolic features. These were classified into 80 compound classes, including 16 phenolic compound classes. Significant differences were observed among the three extraction methods, and UHPAEE extracts exhibited higher levels of phenolic acids and flavonoids. In addition, the extract exhibited enhanced antioxidant activity, along with α-amylase and α-glucosidase inhibitory activities in vitro. These findings demonstrate the potential of UHPAEE as an effective integrated strategy for improving polyphenol extraction from dark tea.