Comprehensive evaluation of thermal processing on the edible quality, flavor and starch properties of Chinese yam

This study systematically evaluated the effects of 3 thermal processing (baked, steamed, and boiled) on the overall quality of yam. Results showed that thermal processing significantly affected the appearance, color, sensory acceptability, and nutritional components of yams, especially the soluble sugar and amylose contents, and texture. HS-SPME-GC-MS identified 10 characteristic volatile flavor compounds (VOCs), and 5 contributing most to the overall flavor of yam. LC-MS detected 199 significantly different and 26 unique non-VOCs. These non-VOCs mainly involve the synthesis and metabolism of amino acids, fatty acids, starch, and bioactive compounds. Moreover, thermal processing promoted starch crystalline region disintegration, double helix disassembly, and intermolecular force weakening, thereby enhancing starch hydration (maximum increase nearly 150%) and digestibility (maximum increase to 51.63%). Overall, baking yam has a better flavor, while steaming and boiling yam are easier to digest. These findings provide a theoretical basis for yam processing and consumption. • Thermal processing alters the nutritional and edible qualities of yam. • Different thermal processing methods result in variations of flavor and taste. • 5 key VOCs and 26 unique non-VOCs were identified. • Processing alters starch structure, physicochemical properties and digestibility. • Baking yam has better flavor, steaming and boiling yam are easier to digest.