Physicochemical and Sensory Evaluation of Biscuits Produced from Composite Flour of Wheat and Fermented Cowpea Hull
Clement C. Ezegbe *
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Felix E. Okpalanma
Department of Food Science and Technology, Madona University, Nigeria.
Sunday K. Okocha
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Eunice N. Odoh
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Josephine C. Ohuche
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Sylvester N. Orjiakor
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Johnwilfred C. Ndulue
Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: This study investigated the physicochemical and sensory properties of biscuits made from a composite flour of wheat and fermented cowpea hull.
Study Design: Mixture Design was adopted for this study.
Place and Duration of Study: Department of Food Science and Technology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria, between January 2023 and March, 2024.
Methodology: Cowpea hulls were cleaned, soaked, boiled, dehulled, and fermented with Rhizopus oligosporus for 48 hours. The resulting hulls were dried, milled, and blended with wheat flour in varying ratios (95:5, 90:10, 85:15, 80:20, 75:25, and a 100% wheat control). The composite flours were then used to produce biscuits, which underwent proximate, physical, and sensory evaluations using a 9-point hedonic scale.
Results: Results showed that the inclusion of fermented cowpea hull significantly increased moisture (9.75-11.55%), ash (1.59-2.85%), crude protein (10.75 - 12.05%), fat (0.96 - 1.95%), and crude fibre (4.55 - 5.30%) content, while carbohydrate content decreased (72.37-66.31%). Physically, the biscuits exhibited an increase in thickness (4.40 - 5.55 mm) and weight (9.64 - 11.85g), but a decrease in height (4.85 -3.90 cm) and breaking strength (3.70 - 2.65). Sensory evaluations indicated that higher levels of fermented cowpea hull negatively impacted the biscuits' quality in terms of colour (7.25 - 6.15), taste (7.45 - 6.25), aroma (7.15 - 6.75), flavour (7.60 - 6.40), and overall acceptability (7.50 - 6.60). The biscuit with 5% fermented cowpea hull was the most acceptable (7.05), after the control sample made with 100% wheat (7.50).
Conclusion: This study demonstrates that nutritionally enhanced biscuits can be produced using a blend of wheat and fermented cowpea hull, though the inclusion should not exceed 10% as to maintain high sensory acceptability.
Keywords: Cowpea, acceptability, biscuit, Rhizopus oligosporus, protein, taste