Different thermal processing techniques enhance bioactive compounds, digestibility of Gastrodia elata during in vitro digestion by altering cellular structure and cell wall polysaccharides

Steaming is a key traditional processing method for Gastrodia elata to enhance its bioactivity. This study investigated the effects of four thermal processing methods (atmospheric steaming (AS), boiling (CB), and high-pressure steaming (HPS: 60/100 kPa) on the bioactive compounds, digestibility of G. elata during in vitro digestion, cellular structure. HPS-100 (5 min) optimally preserved antioxidant capacity, demonstrating 761.82±30.98 mg/100g parishin E (PE) through pressure-accelerated inactivation of β -Glucanase. Microstructural analysis by light microscopy (LM) and transmission electron microscopy (TEM) revealed HPS-induced cell wall swelling and middle lamella dissolution, while polysaccharide profiling showed water-soluble pectin (WSP) increased 2.4-fold ( P <0.05), correlating strongly with bioactive release. During in vitro digestion, antioxidant activity declined sequentially (oral>gastric>intestinal), yet HPS samples maintained superiority due to matrix encapsulation of thermostable compounds. Acetylcholinesterase inhibition peaked in oral phase via α-amylase bioactivation but decreased 68% intestinally. Crucially, HPS-100 enhanced digestive stability by forming heat-induced protective molecular assemblies resistant to pH and enzymatic degradation. These results demonstrate pressurized steam processing maximizes functional integrity of G. elata by restructuring cell walls and optimizing bioactive accessibility. • Effects of thermal processing methods on bioactive compounds, digestibility of G. elata were studied. • HPS-100 maximizes parishin via pressure-accelerated β -Glucanase inactivation • Cell wall swelling and pectin increase enhanced bioactive release in G. elata. • HPS processing improved bioaccessibility of G. elata compounds.