Optimisation of nutritious biscuits formulation through fortification with catfish (Clarias gariepinus) and Ulva sp. flours using response surface methodology

The optimisation of biscuit formulation fortified with catfish ( Clarias gariepinus ) and Ulva sp. flours was studied. The Response Surface Methodology (RSM) was employed to determine the best formula using three independent variables, namely wheat, catfish, and Ulva sp. flour with upper and lower limits of 33.0–36.5%, 8.0–11.5%, and 0.5–2%, respectively. Analysis was performed on protein content, taste, texture, hardness, and colour of the biscuits and was verified by their nutritional quality, including proximate, dietary fibre, sensory and physical properties, and amino acid profiles minerals, vitamins, as compared to commercial biscuits. The results indicated that the biscuits fortified with catfish and Ulva sp. contained 19.38 ± 1.02% of protein, 11.20 ± 0.76% of fat, 63.52 ± 0.89% of carbohydrate, 495 kcal of energy, and 20.83 ± 1.87% of a dietary fibre, which were meeting the Recommended Dietary Allowance (above 20%) for energy, protein, dietary fibre, minerals (magnesium, potassium, iron and zinc), vitamin A, and B6. The biscuits also contained essential amino acids exceeding the Recommended Dietary Allowances (RDA)  standards for children established by FAO/WHO, thus it is recommended to prevent malnutrition.