Effect of Fruit Maturity Stage on Some Physicochemical Properties of Jatropha Seed Oil and Derived Biodiesel

摘要

The quality of a feedstock in biodiesel production is of paramount importance, and Jatropha seed oil is no exception. This study investigates the influence of the fruit maturity stage on the physicochemical properties of Jatropha seed oil and the derived biodiesel. Free fatty acid content, peroxide value, moisture content, density, and kinematic viscosity are some of the important quality parameters of oil and biodiesel. Results from this investigation have revealed that free fatty acid content and peroxide value of seed oil varies as Jatropha fruits mature from green to brown dry. The free fatty acid content in Jatropha seed oil increases continuously with seed maturity following the three-order polynomial trend. The free fatty acid content in Jatropha seed oil from the investigated geographical locations in Botswana ranges from 0.2 to 0.7% for the four different fruit maturity stages. Similarly, the peroxide value of Jatropha seed oil increases gradually and linearly with fruit maturity. The peroxide value of Jatropha seed oil ranges from 1.2 to 3.7 mEq/kg oil, while that of derived biodiesel ranges from 2.1 to 4.4 mEq/kg oil during the four different fruit maturity stages. However, the variation of density and kinematic viscosity of both Jatropha seed oil and derived biodiesel with fruit maturity is insignificant. Moisture content in Jatropha seeds varies as fruits mature from green to brown dry.