Effect of red rice-cassava composite flour on the sensory and quality attributes of gluten-free biscuits

Aim: This study aimed to determine the best formulation of gluten-free biscuits made from red rice and cassava composite flour and to evaluate their physicochemical properties, shelf life, and consumer acceptability. Methods: Five biscuit formulations (F1: 100:0, F2: 75:25, F3: 50:50, F4: 25:75, F5: 0:100; red rice flour:cassava flour) were prepared. Sensory evaluation using a nine-point hedonic scale identified the optimal formulation. The selected biscuit was further analyzed for proximate composition, dietary fiber, total energy, and physical properties (hardness, color, spread ratio, and bulk density). Shelf life was monitored over eight weeks through microbiological counts, water activity, and texture changes. Consumer acceptance was assessed via a market survey. Results: F3 (50:50) achieved the highest scores for color, aroma, taste, crispiness, and overall acceptance. It contained lower moisture (2.87%) and protein (5.45%) but higher ash (0.81%), carbohydrate (72.46%), dietary fiber (3.57%), and energy (474.03 kcal/100 g) than the control (p < 0.05). Fat and crude fiber contents did not differ significantly among the formulations (p > 0.05). F3 showed lower hardness, darker color, higher spread ratio, and greater bulk density. Microbial counts remained at < 10 CFU g⁻1 and water activity ≤ 0.65 during storage, while hardness gradually decreased. Over 70% of consumers rated the product as highly acceptable. Conclusions: A 50:50 red rice-cassava formulation produced gluten-free biscuits with favorable nutritional, physical, and sensory qualities and good storage stability, indicating strong potential as a functional snack product.