Evaluation of High-Protein Red Lentils in the Development of Gluten-Free Functional Bread

Abstract The increasing demand for nutritionally enhanced and gluten-free functional foods has catalyzed innovation in bread formulations targeting individuals with coeliac disease and health-conscious consumers. This study aimed to develop a gluten-free bread utilizing high-protein red lentil flour, optimized through a Box–Behnken experimental design. Lentil flour, buckwheat flour, and olive oil were selected as independent variables, while almonds, hazelnuts, pumpkin seeds, and spices were included at fixed levels to enhance nutritional and sensory properties. Fifteen formulations were evaluated through sensory analysis, and statistical optimization identified the ideal composition as 50 g lentil flour, 45 g buckwheat flour, and 6.5 g olive oil. The optimized bread exhibited superior sensory acceptability and a favorable nutritional profile, delivering 12.82 g protein, 8.07 g dietary fibre, 58.85 mg omega-3 fatty acids, and 0.52 mg vitamin E per 100 g, with gluten content well below the Codex Alimentarius threshold (< 20 ppm). The product was free from animal-derived ingredients and chemical additives, making it suitable for vegan and lactose-intolerant populations. Despite a relatively high fat content (11.77 g/100 g), the predominant fatty acid was oleic acid (64%), supporting cardiovascular health. These findings demonstrate the feasibility of producing a nutritionally dense, sensory-acceptable, and additive-free gluten-free bread using sustainable plant-based ingredients. By providing a scientifically optimized formulation that addresses key nutritional and sensory challenges in gluten-free baking, this study makes a meaningful contribution to the literature on functional food innovation, sustainable ingredient utilization, and inclusive dietary product development.