A study on optimizing functional oats and quinoa cookies: the role of fiber in enhancing texture, taste, and sensory acceptance of Rebaudioside A–sweetened formulation

Background: Since obesity, diabetes, and celiac disease are becoming global health issues, interest in low-calorie and gluten-free food consumption has increased over time. Sugar alternatives, such as Rebaudioside-A, have gained attention due to their health benefits and natural origins. In this study, we investigated the effects of Rebaudioside-A as a sugar substitute and inulin as a functional ingredient in gluten-free oat and quinoa cookies. Objective: This study aimed to develop and optimize gluten-free, dairy-free, and sugar-free functional cookies formulated from oats and quinoa. Rebaudioside-A was used as a complete substitute for traditional sugar. As an alternative, a dietary fiber source, inulin, was incorporated with three primary objectives: enhancing the product's sensory acceptability and nutritional value and improving its binding properties to ensure structural integrity. Methods: Oats and quinoa-based gluten-free cookies were formulated in three variations: sugar-based (SuC, control), Rebaudioside-A-based (StC), and Rebaudioside-A and Inulin-based (InStC). Water activity and texture analysis were performed on the same day of baking and after 5 days. Sensory analysis (n=103) was carried out following ethical approval. Results: Sensory evaluation revealed that InStC had improved acceptability compared with StC alone due to the inclusion of inulin, with no difference in odor or color. Based on the sensory study results, there was no perceived difference between odor and color for the three formulations. Suc and InStC showed the same water activity and physical texture analysis results, and the texture sensory analysis also found the two products to be not different. Conclusion: This study demonstrates that replacing sugar with Rebaudioside-A and incorporating inulin in gluten-free cookies is a novel and viable approach for developing functional, low-calorie baked goods. While Rebaudioside-A alone posed challenges in terms of aftertaste acceptability, adding inulin improved the sensory profile in terms of taste and texture.