Potato Flour, Oat Bran, and Inulin as Functional Ingredients in Gluten-Free Biscuits: Glycemic Index Reduction and Physicochemical Characterization Improvement

Low glycemic index (GI) food which is nutritious would be far more desirable for health. Oat bran and inulin have a wide range of food applications, as an additive to reduce the GI and increase dietary fiber content. This work aimed to formulate low GI and gluten-free biscuits by using potato flour, indica rice flour, oat bran, and inulin. Physical properties of biscuits such as in vitro digestibility, spread ratio, and sensory acceptance were determined. Extreme vertices design was applied to investigate the interactions among components. The presence of inulin decreased the water holding capacity (WHC) and pasting property of flour mixes, and increased the sensory acceptance and the darkness of biscuits. Oat bran increased WHC, pasting properties, spread ratio, and hardness compared to biscuit with potato flour and indica rice flour only. The incorporation of oat bran and inulin significantly (p < 0.05) reduces the glycemic index of biscuits and enhances the taste, flavor, and overall acceptability. The incorporation of potato flour and oat bran (p < 0.05) affected the L*, a*, b* and spread ratio significantly. When potato flour and indica rice flour at a ratio of 3:2 (PIRM):oat bran:inulin was 50%:28%:22%, the biscuit resulted in low GI value of 44.64. The incorporations of oat bran and inulin could represent a valuable strategy to enhance gluten-free bakery products’ physicochemical properties and sensory acceptability and reduce the in vitro glycemic response.