One-step microwave curing-dehydration of Gastrodia elata Blume: Relationship between phytochemicals, water states and morphometric characteristics

•Gastrodia elata – a vital medicinal crop contains gastrodin as major compound.•Microwave curing-drying significantly increases phytochemical content by 3.4 times.•Analysis shows increase in phytochemicals (HPLC); changes to water states (LF-NMR).•3D X-ray microscopy, SEM depicted arrangement of pore network and vascular tissues.•Changes to starch and hydrolytic enzymes partially cause increase in gastrodin.