Structural characteristics, biological activities, and rheological properties of polysaccharides from different cultivars of strawberry collected in China.

Strawberry polysaccharides (SPs) are vital bioactive components contributing to the fruit's health benefits. However, the impact of cultivar variation on the physicochemical, bioactive, and rheological properties of SPs remains underexplored. In this study, polysaccharides were extracted from four strawberry cultivars grown in Guizhou Province-Kaorino (SP-XY), Akihime (SP-ZJ), SnowWhite (SP-BXGZ), and Benihoppe (SP-HY)-and systematically analyzed for their physicochemical properties, flow behavior, and inhibitory effects on α-glucosidase and non-enzymatic glycation. Significant variations were observed in chemical composition, monosaccharide profiles, and molecular weight distributions. SP-XY exhibited the highest molecular weight (642.59 kDa) and uronic acid content (11.63 %), which correlated with enhanced α-glucosidase inhibition and stronger suppression of fructosamine and advanced glycation end-product (AGEs) formation. All SPs exhibited uncompetitive inhibition of α-glucosidase, primarily mediated by static fluorescence quenching, with SP-HY demonstrating the strongest binding affinity to the enzyme-substrate complex. Fluorescence and FT-IR spectroscopy confirmed that SPs induced secondary structural alterations in α-glucosidase, resulting in reduced enzymatic activity. Rheologically, SP-HY exhibited the highest viscosity, the lowest critical strain rate, and the strongest gel-forming potential, suggesting its suitability as a thickener or stabilizer in diabetic-friendly food formulations. This study enhances the understanding of the structure-function relationships of strawberry polysaccharides, offering insights into their bioactive and functional properties for food and health applications.