Comparative evaluation of high-pressure processing and conventional pasteurization in cold brew green tea: In vitro digestibility, bioavailability, and nutrient stability

High-pressure processing (HPP) is a non-thermal alternative to thermal pasteurization (Ps) for preserving cold-brewed green tea. This study compared HPP (300, 450, and 600 MPa for 5 and 10 min) with Ps for quality, microbial safety, and in vitro digestive stability. Moderate HPP treatments preserved color, ascorbic acid, and catechins effectively. HPP retained more non-galloylated catechins (GC, EGC, and EC) than Ps, which could reduce bitterness and astringency, though formal sensory evaluation is needed to confirm this. Among the conditions, 600 MPa for 5 min was optimal for overall quality, while 600 MPa for 10 min ensured maximal microbial inactivation. During digestion, catechins, total phenolic content, and antioxidant activity (DPPH, FRAP) decreased significantly ( p < 0.05) but retained >70 %, demonstrating satisfactory stability. Overall, HPP is an effective method to maintain both the nutritional quality and microbial safety of cold-brewed green tea. • HPP at 300–450 MPa (5–10 min) and 600 MPa (5 min) improve nutritional quality. • HPP at 600 MPa for 10 min negatively impacts tea quality. • PCA analysis revealed that HPP pressure and duration altered volatile profiles significantly. • HPP at 600 MPa for 5 min: Optimal for quality and microbial inactivation. • In vitro digestion showed over 70 % recovery in catechins, phenolic content, and antioxidants.