Chemical characterization of crude oil from Pennisetum glaucum (L.) R. Br

Pearl millet oil is extracted from the grains of a cereal grown in arid and semi-arid regions, recognized for its climatic resistance and nutritional value. Pearl millet oil has a fatty acid profile similar to maize oil; however, it exhibits greater antioxidant activity and contains bioactive substances distinct from those found in maize oil. The crude pearl millet oil was extracted by solvent method and analyses for fatty acid profile determination, chemical analysis, Rancimat analysis, thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC) were carried out. The results showed that the oil contains 22.09% saturated fatty acids, especially palmitic acid (17.30%), 26.42% monounsaturated fatty acids, especially elaidic acid (26.16%), and 50.83% polyunsaturated fatty acids, predominantly linoleic acid (48.03%). Acidity (3.30 mg KOH/g), peroxide value (9.01 mEqO2/kg) and saponification index (22.79 mg KOH/g) were measured. Rancimat analysis revealed induction times of 6.41 and 6.50 hours for the samples. TG/DTG analysis showed a mass loss of 2.7% between 180 and 280 °C and 97.3% between 280 and 480 °C, associated with the thermal degradation of the fatty acids. The melting and crystallization curves recorded exothermic peaks at -41 °C and -18 °C, and endothermic peaks at -4 °C and -32 °C, providing a detailed overview of the phase changes of the fatty acids. These data are crucial to understanding the characteristics of pearl millet oil and its possible industrial and food applications.