Characterization of Oils and Solid Residues Obtained from <i>Bauhinia variegata L.</i> and <i>Pachira glabra pasq.</i> Seeds Through the Solvent Extraction Method

Abstract

Vegetable oils derived from non-edible seeds are excellent sources for producing biodiesel which serves as an alternative to fossil fuels. In this study, products viz vegetable oils and solid residues obtained from solvent extraction method of <i>Bauhinia variegata</i> and <i>Pachira glabra</i> seeds were characterized according to standard norms to evaluate their energy potential. The oils obtained have a free fatty acid content of 2.31 wt% and 13.6 wt%, a kinematic viscosity of 12.45 and 3.24 mm²/s, an iodine value of 17.26 and 12.37 (g of I<sub>2</sub>/100g of oil), a saponification value of 207.57 and 183.03 (mg of KOH/g of oil), a peroxide value of 10 and 8.06 (meq O<sub>2</sub>/kg of oil), and a calorific value of 40.66 and 65.08 MJ/kg, respectively. Furthermore, the physicochemical analysis of the oils revealed that they are excellent choice for biodiesel production. In addition, the proximate analysis of the solid residues of <i>Bauhinia variegata</i> and <i>Pachira glabra</i> showed high level of protein, fiber, and total carbohydrates with respective values of 34.79 and 30.41 wt%, 10.44 and 15.16 wt%, and 47.50 and 52.92 wt%. Mineral analysis indicated a high concentration of minerals, particularly potassium, sodium, calcium, and phosphorus. The solid residues exhibit anti-nutritional properties, making it suitable for various applications such as bioconversion by black soldier fly larvae, bioelectricity, biogas production, and biofuels among others.