Quality indicators of extracted sunflower and rapeseed oil obtained with hexane and ethyl alcohol solvents

Abstract

The relevance of the conducted research is conditioned by the increase in demand for oilseeds with improved and environmentally friendly qualities, namely, the replacement of a dangerous solvent in the extraction process of processing oilseeds. In this regard, this paper is aimed at investigating the use of an organic solvent, such as ethanol, in extraction technology that is safer for human health. The leading approach to studying this problem is Soxhlet extraction and microwave extraction using hexane and ethanol solvents. The fatty acid composition of the resulting product was analysed by gas chromatography. In the proposed microwave method of oil extraction with a "green" solvent, which is ethyl alcohol, physical and chemical parameters were studied and compared with those obtained by the Soxhlet method. The efficiency of microwave processing is related to the heating process, which significantly increases the internal pressure of cells, which causes their destruction. A barodiffusion flow is created, which contributes to a significant increase in the yield of the extraction oil concentration by 1.4-1.8 times over the same time period and a decrease in the extraction process time by almost 3 times. The oil obtained by extraction of raw materials in a microwave field with a solvent ethyl alcohol is more resistant to oxidation, as evidenced by a decrease in the numbers: peroxide from 4.8 to 3.8, and anisidine from 0.25 to 0.2. The acid number, which characterises the degree of freshness of the resulting oil, also decreased from 2.5 to 2.1. The research results show that the use of microwave extraction with a polar solvent, which is ethyl alcohol, was effective in improving the quality properties of the extracted oil. The use of a "green” solvent does not degrade the quality of the finished product, unlike hexane, which is harmful to human health. The materials of the study are of practical value for the fat and oil industry, namely, in the technology of extraction of oilseeds

Keywords

• solvents
• extraction
• hexane
• ethyl alcohol
• microwave energy
• fatty acid composition