Flos Trollii Polyphenol-Fortified Noodles: Dual Enhancement of Textural Properties and Reduction of In Vitro Starch Digestibility

Growing attention focuses on the glycemic index (GI) of staple foods, driven by the critical importance of blood glucose management for diabetic patients. This study investigated the influence of Flos Trollii polyphenol (FTP) on wheat noodle quality and starch digestion kinetics, focusing on its potential as a natural additive for improving nutritional value and reducing glycemic response. The incorporation of 0%–2% FTP enhanced noodle texture, reducing cooking loss by 33.5% and improving sensory attributes at concentrations ≤ 1.5%. Structural analyses (SEM, XRD, FTIR) revealed formation of V-type crystalline complexes between FTP and starch alongside gluten network reinforcement, thereby restricting digestive enzyme accessibility. DSC confirmed elevated thermal stability with gelatinization enthalpy increasing from 3.01 to 5.00 J/g, supporting starch-polyphenol interactions. In vitro digestion demonstrated that 1.5% FTP significantly decreased digestible starch content by 57% and predicted glycemic index (pGI) by 30.9% (65.18±1.09 compared to 94.40±3.15 in the control), primarily due to enzyme inhibition and complex formation. These findings highlight the dual role of FTP in enhancing noodle quality while reducing starch digestibility, providing a natural strategy for developing diabetes-friendly foods.