Extraction and Characterization of Jatropha Curcas Seed Oil from Selected Regions in Eastern Uganda

Abstract

The global imperative to find sustainable and renewable energy sources has intensified research into non-edible biofuel feedstock. Jatropha curcas is a promising candidate due to its high oil content and ability to grow on marginal lands, making it particularly relevant for countries like Uganda seeking to enhance energy security and promote rural development. However, a lack of localized data on the oil's properties hinders its industrial adoption. This study aimed to address this gap by extracting and characterizing Jatropha oil from seeds sourced from Mbale and Iganga districts, Eastern Uganda. Oil was extracted from prepared Jatropha seed powder using the Soxhlet method with n-hexane as the solvent. The extracted crude oil was then subjected to a series of standard physicochemical analyses to determine its quality and suitability for industrial applications. These tests included the determination of oil yield, Acid Value, Free Fatty Acid (FFA) content, Saponification Value, Iodine Value, and Peroxide Value. Fourier Transform Infrared (FTIR) spectroscopy was also used to identify the primary functional groups present in the oil. The study found a high oil yield of 43.7% (w/w), confirming the viability of the local Jatropha variety as a rich source of oil. The physicochemical analysis revealed an Acid Value of 5.82 mg KOH/g (corresponding to 2.93% FFA), a Saponification Value of 194.5 mg KOH/g, an Iodine Value of 103.6 g I₂/100g, and a Peroxide Value of 4.15meq O₂/kg. The FTIR spectrum confirmed the triglyceride structure of the oil, with characteristic peaks for ester carbonyl (1744 cm⁻¹) and long aliphatic chains (2922 and 2853 cm⁻¹). The results indicate that Jatropha oil from Eastern Uganda is a high-quality feedstock with properties comparable to those reported in international literature. While the high oil yield supports its economic potential, the elevated FFA content necessitates a two-step (acid-base) process for efficient conversion to biodiesel. The favorable saponification and iodine values suggest its suitability for various industrial applications, including soap production. This study provides critical baseline data that supports the development of a Jatropha-based value chain in Uganda and informs future research into process optimization and agronomic practices.