Waste orange seeds (Citrus sinensis seed) transformation, a viable industrial bio-oil: Oil extraction, physicochemical characterization and vital instrumental analyses studies

Abstract

The processing of Petroleum-based oil has contributed to environmental challenges such as climate change. Recently, research attention has been shifted to oil extraction from different non-edible seeds as a suitable substitute. Accordingly, this study examines the physiochemical characterization, and the effect of extraction temperature on the yield of waste Citrus sinensis seed [orange seed (OS)] bio oil. Studies on the prevalent functional group, fatty acid methyl ester compositions and thermal oxidative stability were carried out using the Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectroscopy (GCMS) and differential scanning calorimetry (DSC), respectively. The oil content of the OS bio oil was 46.26%w/w. The high iodine number (31.47 mg/100 g) and low pour point (4.50 °C) of the OS bio oil showed its high content of unsaturated fatty acid. The FTIR functional group of the OS bio oil showed predominantly alkane of CH stretching, aldehydes, esters, and carboxylic acid. The chemical composition of the OS bio oil as determined by GCMS (massHunter/library/NIST 14.1) showed the occurrence of octadecadienoic and oleic acids as poly-saturated and saturated fat found in plant glycosides and vegetable fats and oil. The DSC thermal stability analysis showed the possible existence of mixed triglycerides. Finally, the result from the physiochemical characterization compositions, and functional group the OS bio oil indicated its potential as a suitable substitute for petroleum-based oil.