Physicochemical properties, kinetics, and thermodynamics study of oil extraction from pearl millet bran

Abstract

The increasing demand for edible oils and the need for sustainable waste management have driven research into alternative oil sources such as millet bran. This study focuses on the kinetics and thermodynamics of oil extraction from millet bran using a Soxhlet extractor with n-hexane as the solvent. The maximum oil yield from millet was observed to be 10.78%, 13.23%, and 15.08% at temperatures of 303, 313, and 323 K respectively. The physicochemical properties, including iodine value, ash content, and density, were analyzed alongside FTIR and GC-MS analysis for characterization, confirming the extracted material as oil. The activation energy (Ea) for millet oil extraction was determined to be +7.8990 kJ/mol. Thermodynamic parameters were also assessed, with activation enthalpy (∆H) recorded at +5413 kJ/mol, activation entropy (∆S) at -8.634 kJmol⁻¹K⁻¹, and Gibbs free energy (∆G) values indicating an endothermic and non-spontaneous reaction. These findings contribute to optimizing pearl millet oil extraction and its potential application in edible oil production.