Multi-scale structure, physicochemical properties, and structure-property relationships of chayote tuber starch: A...

Chayote tuber starch (CTS) is a promising unconventional starch resource, yet its structural features and functional properties remain insufficiently characterized. In this study, the structural characteristics and physicochemical and functional properties and in vitro digestibility of chayote tuber starch (CTS) were systematically characterized using potato starch (PTS) as a reference. Furthermore, principal component analysis (PCA) was performed to elucidate the structure-property relationships of the two starches. Compared with PTS, CTS exhibited lower double-helix content (39.88%) and relative crystallinity (20.59%), as well as a smaller average granule size (16.05 μm), suggesting a less ordered molecular structure. The higher amylopectin (AP) content in CTS facilitated starch granule swelling during gelatinization, contributing to a higher peak viscosity (6346 mPa·s) and enhanced viscoelasticity. In contrast, the greater amylose (AM) content in PTS promoted stronger gel formation, resulting in increased gel hardness and improved textural characteristics. In vitro digestion results showed that native PTS contained a higher level of resistant starch, whereas CTS had higher contents of rapidly digestible and slowly digestible starch. Overall, CTS exhibited favorable hydration, rheological, freeze-thaw stability, and post-gelatinization slow-digestion characteristics, suggesting that CTS may be a promising tuber starch resource for further evaluation in food processing applications.