Modification of the microstructure and cell wall polysaccharides alters drying behavior and biological activities of Gastrodia elata by high hydrostatic pressure pretreatment

This study investigated the effects of high hydrostatic pressure (HHP: 100–300 MPa) on the microstructure, cell wall polysaccharides, drying kinetics, and bioactivity retention of Gastrodia elata (G. elata). Microstructure analysis revealed HHP-induced cellular damage of G. elata, including wall rupture and intercellular space expansion, proportional to pressure intensity. HHP altered pectin fractions, converting covalently/ionically bound polysaccharides (CSP, NSP) into water-soluble forms (WSP), weakening cell adhesion. Fourier transform infrared spectroscopy and principal component analysis confirmed structural modifications in pectin matrices, correlating with pressure-dependent depolymerization. Drying time decreased by 32.46 % at 250 MPa, while rehydration improved due to microstructural changes. HHP enhanced retention of phenolic compounds, flavonoids, and polysaccharides of G. elata during in vitro digestion, with elevated gastrodin and parishins bioavailability. Furthermore, HHP-treated samples exhibited superior inhibition of acetylcholinesterase (48.65 %), α-glucosidase (54.28 %), and xanthine oxidase (42.03 %), linked to enhanced bioactive accessibility. These findings demonstrate HHP's potential to optimize G. elata processing while preserving functional properties.