Tingting Zhang

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.

This study investigated quality traits and volatile organic compounds (VOCs) in two winter wheat varieties with different gluten types (Xinliang 169, medium-strong gluten, and Xinliang 607, medium-weak gluten) across five grain-filling stages (5, 10, 20, 30, and 40 days after anthesis, DAA) under heated headspace conditions (80 °C). During grain filling, moisture and total soluble sugar (TSS) decreased significantly, whereas hardness, thousand-kernel weight (TKW), and starch content increased significantly. Protein followed a typical “high–low–high” pattern. Using headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), 80 and 125 VOCs were detected, respectively. A total of 19 preliminarily prioritized candidate odorants (e.g., 1-penten-3-one, 2,3-butanedione, and 3-methylbutanal) were screened using orthogonal partial least squares discriminant analysis (OPLS-DA, VIP > 1) and relative odor activity value (ROAV ≥ 1). Based on literature odor descriptors, the aroma profile shifted from green, malty notes during early grain filling to waxy, fatty, and grain-like notes during late grain filling. XL169 was characterized by grassy-green, malty, and fatty grain-like notes, whereas XL607 was dominated by creamy, buttery, and sweet-fruity woody notes. Correlation analysis revealed significant correlations between high-priority candidate odorants (2,3-butanedione, (E)-2-octenal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone) and quality traits (starch, TSS, and protein). These exploratory findings provide a preliminary reference profile for understanding how grain filling affects wheat VOCs.