Comparative Analysis of the Structural and Digestibility Properties of Starches from Ten Common Coarse Grains

Coarse-grain starches are promising raw materials for developing diversified functional food ingredients, particularly low-glycemic products. However, the systematic structure-function relationships among multiple coarse-grain varieties remain poorly understood. This study aimed to comprehensively characterize the structural, processing, and digestive properties of ten coarse-grain starches to provide a fundamental basis for their targeted industrial utilization. Multiple analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), rapid visco analysis (RVA), and in vitro simulated digestion, were employed to characterize the structural, thermal, rheological, pasting, and digestive properties of the starches. The tested starches were classified into two crystalline types, and significant differences were observed among samples in short-range molecular order, gelatinization behavior, gel rheological properties, pasting characteristics, and the distribution of three digestion fractions. Pearson correlation analysis revealed structure-function correlations, showing that crystalline ordering plays an important role in starch gelatinization behavior, whereas molecular packing is closely associated with pasting performance and in vitro digestibility. The distinct differences in starch properties, together with the identified structure-function relationships, provide a basis for targeted raw material selection in food processing and the development of functional foods with tailored digestibility characteristics.