Effects of bran-enriched flour blends on the antioxidant properties, nutritional quality, and glycemic control of high-fiber biscuits

Aim: The increasing prevalence of type 2 diabetes has heightened the demand for low glycemic index food products, leading to the exploration of alternative baking ingredients. This study assesses the effects of bran-enriched flour blends on the sensory, physical, nutritional, and antioxidant properties and glycemic control of high-fiber biscuits. Methods: Wheat, corn, sorghum, and sweet potato were obtained from the market. Linear programming (LP) optimized fiber content to create four high-fiber flour blends assessed for functional properties [water absorption capacity (WAC), oil absorption capacity (OAC), foaming capacity (FC), and stability]. Four high-fiber biscuits were developed and evaluated for nutritional composition (ash, crude fibers, water, carbohydrates, proteins, fats, Zn, Fe, Mg, Na, Ca, and P), sensory attributes (color, aroma, texture, and taste), physical properties (thickness, diameter, weight, spread ratio, browning index; L, a, and b), antioxidant properties (DPPH and FRAP activities), glycemic response, and in vitro glucose-binding capacity. Results: The formulated flours exhibited water and oil absorption capacities ranging from 1.95% to 2.70%, with the highest oil absorption in formulated flour 3. FC and stability varied significantly, with the control showing the highest values. Swelling power ranged from 1.27 cm3/g to 2.03 cm3/g. High-fiber biscuits had higher fiber (6.06–12.44%), protein (9.48–11.31%), Fe (3.01–4.55 ppm), and Mg (34.37–78.05 ppm) content, and lower carbohydrate (50.88–59.57%) contents compared to the control. They also demonstrated enhanced antioxidant properties with higher phenolic content (201.91–503.18 mg GAE/100 g) and DPPH-scavenging activity (0.07–0.27 µg/mL). Sensory evaluation indicated general acceptance. Biscuits 2 and 3 maintained steady blood glucose levels over 90 min, with biscuit 3 showing the highest in vitro glucose binding capacity (43.4 ± 4.3%). Conclusions: Incorporating diverse bran and flour types improves biscuit quality, particularly in blends like F2 (wheat flour, corn bran, and sorghum bran) and F3 (wheat flour, corn bran, sweet potato flour, and sorghum bran), offering beneficial options for diabetics.