Nutritional, Phytochemical and Sensory Evaluation of Functional Biscuits from Tigernut (Cyperus esculentus) and Afzelia africana Flour Blends

Aims: Tigernut (Cyperus esculentus L.) and Afzelia africana are nutritionally rich, gluten-free indigenous crops. The unexplored functional food potential in composite biscuit production needs to be studied to address protein-energy malnutrition, micronutrient deficiencies, and rising consumer demand. Study Design: This original research article used a completely randomized design (CRD). Biscuits were produced by substituting tigernut flour with Afzelia africana seed flour in this order: Control sample = 100% Tigernut flour; A = Afzelia africana (10%) + Tigernut (90%) flour; B = Afzelia africana (20%) + Tigernut (80%) flour. Place and Duration of Study: The study was conducted in the Food Science and Technology department's laboratory at Chukwuemeka Odumegwu Ojukwu University, Igbariam Campus, in June 2024. Methodology: Flour preparation and baking followed standard methods. Proximate composition, minerals, vitamins, phytochemicals, DPPH radical scavenging activity, and sensory acceptability were studied. Results: Increasing Afzelia africana substitution was associated with significant dose-dependent increases in crude protein (3.66-5.52 g/100g), crude fiber (0.48-2.29 g/100g), crude ash (1.05-2.78 g/100g), calcium (172.18-273.62 mg/100g), magnesium (34.52-38.70 mg/100g), potassium (290.72-305.76 mg/100g), thiamine (0.51-0.88 mg/100g), riboflavin (0.43-1.08 mg/100g), niacin (0.16-1.17 mg/100g), total phenolic (12.87-16.82 mg GAE/100g) and flavonoid (4.49-6.69 mg/100g) content, alongside a progressive reduction in DPPH IC50 indicating enhanced antioxidant activity. All moisture values (3.49-5.31 g/100g) were within the recommended range for biscuit shelf stability. The control and sample A were not significantly different (p<0.05) in color, flavor, aftertaste, and overall acceptability. Conclusion: Afzelia africana seed flour enhanced the nutritional value, antioxidant activity, and sensory appeal of tigernut biscuits. A 10% substitution of Afzelia africana seed flour was identified as the optimal formulation. These findings support the use of Afzelia africana seed flour as a functional food ingredient in biscuit production for protein- and micronutrient-vulnerable populations in Nigeria.