Effect of Partial Substitution of Wheat Flour with Kiwifruit Starch on the Quality and Storage Properties of Biscuits

This study investigated the effects of partially replacing wheat flour with kiwifruit starch (KS) at varying ratios (15%, 20%, and 25%; m/m) on the properties of mixed flours, dough processing performance, biscuit quality, digestibility, and storage properties. The results indicated that KS substitution significantly improved the water-holding and oil-holding capacities of mixed flours, facilitated starch gelatinization, and increased the viscoelastic modulus of doughs, but it reduced the stability of the gluten network. Both the mass and thickness of biscuits decreased significantly with increasing KS substitution. The product with 15% and 20% KS substitution showed improved texture and was more crumbly and easier to chew, which was more aligned with the standards for high-quality crispy biscuits. The biscuit with 20% KS substitution received the highest sensory score (8.51) for overall acceptability, having the dual advantages of blood glucose regulation and good sensory acceptability. KS substitution significantly increased the resistant starch content in biscuits to 41.75%-50.11% while significantly decreasing the starch digestion rate and estimated glycemic index (eGI). Notably, 20% and 25% KS substitution reduced the glycemic index (GI) from high to low-medium. Additionally, KS substitution significantly reduced the rates of lipid oxidation and water absorption and improved the storage stability. This study provides theoretical support for the application of fruit-derived starches such as KS in low GI foods.