Comparative study on the effects of different drying technologies on the structural characteristics and biological activities of polysaccharides from Idesia polycarpa maxim cake meal.

To extract oil, the fruits of Idesia polycarpa Maxim (IPM) must first undergo a drying process. This study aimed to investigate how different industrial drying techniques-microwave vacuum drying (MVD), microwave drying, infrared drying, and hot air drying-affect the structural characteristics and bioactivities of IPM cake meal polysaccharides (IPMPs). The results revealed significant differences in the structure and composition of the four IPMPs. MVD-IPMP, dried using MVD, exhibited a lower molecular weight (346.26 kDa), higher uronic acid content (30.74 %), and a distinct triple-helix structure. These structural features contributed to its enhanced antioxidant activity, α-glucosidase inhibition, and prevention of glycation. IPMPs induced secondary conformational changes in α-glucosidase, leading to decreased enzyme activity. Additionally, IPMPs caused static quenching of the enzyme's intrinsic fluorescence, suggesting a specific interaction mechanism, with MVD-IPMP demonstrating the highest binding affinity. These findings suggest that MVD is an effective technique for the large-scale production of high-quality IPMPs.