Effect of Pueraria thomsonii Benth. Powder Addition on the Quality and Starch Digestibility of Flat Rice Noodles

Pueraria thomsonii Benth. is an important medicinal plant with a unique chemical composition, widely used in traditional Chinese medicine. This study investigated the physicochemical, rheological, cooking, and digestibility properties of flat rice noodles fortified with PTBP at levels ranging from 5% to 30% of Pueraria thomsonii Benth. powder (PTBP). The addition of PTBP significantly increased the swelling power, water solubility, and water absorption of rice flour ( p < 0.05) but decreased its peak viscosity. However, an excessive PTBP level (above 20%) deteriorated pasting characteristics, cooking loss, and texture properties. Fourier transform infrared spectroscopy (FTIR) indicated a decrease in the short‐range ordered structure of starch. Scanning electron microscopy (SEM) revealed that PTBP addition resulted in a rough and loose internal structure. In vitro digestibility tests showed that the starch hydrolysis rates were significantly lowered at 25% and 30% PTBP substitution levels ( p < 0.05), with estimated glycemic index (eGI) values reduced by 0.78% and 2.87%, respectively. These findings demonstrate that PTBP supplementation holds promise for improving rice noodle formulations, provided that the inclusion level is carefully optimized to balance nutritional benefits with textural quality.