The influence of pretreatments on the quality characteristics and in vitro biological activity of freeze-dried Thai Tom-Yum ingredients

This study aimed to investigate the effects of pretreatments on quality characteristics, bioaccessibility of phenolic compounds, and antioxidant activities (AA) of freeze-dried Thai Tom-Yum ingredients during in vitro digestion. Hot water (B), steam (S), microwave blanching (MW), ultrasound (US), and blanching with dipping in chemical solution (D) were performed on lemongrass, red onion, kaffir lime leaves, chili, galangal, and coriander. In most samples, D significantly lowered water activity (Aw) and moisture content (MC) while preserving color attributes. D was the best pretreatment with the highest total phenolic compounds (TPC) for lemongrass, red onion, and galangal, US for kaffir lime leaves and chili, and S for coriander. The AA assessed by DPPH and FRAP showed a correlation with TPC values (0.731 and 0.576 at p