Nutritional, Functional, and Mineral Properties of Composite Flour from Orange-fleshed Sweet Potato and Mushroom (Pleurotus tuberregium Sclerotium)

Abstract

The increasing demand for micronutrients to address deficiencies and the worldwide transition to functional foods have made nutrient-enriched flours from underutilized crops a matter of great concern. Orange-fleshed sweet potato (OFSP) contains high levels of beta-carotene (provitamin A), and Pleurotus tuberregium is a good source of dietary fiber, protein, and vital minerals. The composite flour containing OFSP and P. tuberregium sclerotium were formulated in ratio 100:0, 85:15, 80:20, 75:25, 70:30, 65:35 and 100% yellow maize as control. To aid the development of nutrient-rich functional foods, this study examined the proximate composition, functional properties, and mineral content of composite flours and the control sample. A simplex lattice design was employed to prepare composite blends at varying proportions, including 100% OFSP and yellow maize as control samples, which were subsequently analyzed using standard analytical procedures. Proximate analysis revealed moisture (0.38-0.94%), fat (0.93-1.32%), ash (1.62-3.68%), crude fiber (2.50-5.59%), protein (14.20-21.90%), and carbohydrate (67.10-78.88%). The addition of more mushrooms progressively increased protein, fiber, and ash levels. Functional property analysis revealed water absorption capacity (221.00-252.33%), swelling capacity (6.14-9.51%), solubility index (18.33-34.23%), oil absorption capacity (121.00-162.00%), and bulk density (0.53-0.61 g/cm³), which are suitable for various food formulations. The mineral result showed appreciable levels of potassium (222.30-502.57 mg/100 g), calcium (132.68-198.58 mg/100 g), magnesium (110.36-197.81 mg/100 g), and iron (1.17-2.55 mg/100 g). These findings reveal complementary nutritional and functional interactions between OFSP and P. tuberregium sclerotium, indicating that they can be used as health-promoting components in functional foods to enhance protein consumption and reduce micro-deficiencies in susceptible populations.