Stir-frying duration modulates structural characterization and functional properties of Atractylodes macrocephala polysaccharides.

Atractylodes macrocephala Koidz. (Baizhu, BZ) is a renowned herb in Traditional Chinese Medicine. Its bioactive components include volatile oils, lactones, and polysaccharides, with recent studies focusing on how processing techniques like stir-frying influence these compounds' properties. This study investigates the effects of stir-frying on the structural, chemical, and functional characteristics of BZ polysaccharides (BZPs), aiming to optimize their bioactivity. BZ was subjected to stir-frying at 180 °C for varying durations (0, 13, 26, 39, 52 min), followed by ultrasonic extraction and purification via gel filtration chromatography. Five polysaccharide fractions (BZP-1 to BZP-5) were obtained, each representing different molecular weights and monosaccharide composition. Analysis of the apparent morphology using SEM and AFM revealed significant changes in surface texture and particle aggregation with increasing stir-frying time. FT-IR and NMR spectroscopy confirmed structural stability, with key functional groups intact. XRD and Congo red analysis revealed changes in crystallinity and triple-helix formation, while thermal and rheological studies indicated distinct thermal stability and flow behavior among the fractions. Notably, BZP-5 exhibited the highest α-amylase inhibition activity. This study highlights how stir-frying alters the physicochemical properties of BZPs, offering insights into optimizing processing conditions to enhance the therapeutic potential of BZ in various applications.