Abstract
This study investigated the effects of microwave intensity (8, 10, and 12 W/g), vacuum pressure (0.05, 0.065, and 0.08 MPa), and drying temperature (50, 60, and 70 °C) on the drying characteristics, bioactive components, antioxidant capacity, and starch structure of germinated red adzuki beans (GRAB) under microwave vacuum drying (MVD). Drying temperature was the critical factor affecting drying kinetics, color, and γ-aminobutyric acid content. The retention of total phenolic and flavonoid content was governed by microwave-induced structural disruption and thermal degradation. MVD increased gallic acid, quercetin, and chlorogenic acid, but reduced rutin and epicatechin levels. MVD also enhanced antioxidant capacity of GRAB, reduced its gelatinization enthalpy, induced microstructural changes, disrupted the double-helical structure, lowered the relative crystallinity, and cleaved the α-(1,6) glycosidic bonds. Overall, MVD can be considered an effective method for preserving bioactive components and modifying the starch properties to improve the nutritional and functional quality of GRAB.