The reaction efficiency of soybean oil transesterification in supercritical ethanol in a continuous catalyst-free process was investigated under different water concentrations. Experiments were performed at 350 °C and 20 MPa, with an oil/ethanol ratio of 1:40. A fatty acid ethyl ester content of 77.5% was obtained at a flow rate of 1.5 mL/min in a water-free system, while the maximum concentration of ethyl esters reached for a water content of 10 wt % was 68.1% at a flow rate of 1.0 mL/min. Decomposition and trans-isomerization of unsaturated fatty acids were significantly affected by the flow rate, with a pronounced reduction in the ratio of C18:2/C16:0 in the final product compared to the starting oil.

This work investigated the effect of temperature on the reaction efficiency of soybean oil transesterification in supercritical ethanol in a continuous catalyst-free process under different water concentrations and at varying substrate flow rates. Experiments were performed in the temperature range from 250 to 325 °C, at 20 MPa, with an oil to ethanol molar ratio of 1:40. Results showed that temperature and substrate flow rates strongly affected the reaction conversion to fatty acid ethyl esters, decomposition, and trans-isomerization of unsaturated fatty acids, mainly for C18:2 and C18:3. It is shown that the synthesis of esters was favored by the addition of water to the reaction medium and the degradation phenomenon decreased as water concentration increased from 0 to 10 wt %.

No abstract

Traditional olive oil processing includes batch olive paste kneading for 30-60 min. Microwave (MW) treatment of the olive paste have recently shown to continuously provide faster conditioning, while megasound (MS) treatment have been shown to enhance oil extractability. In the present work the virgin olive oil standard parameters, sensory descriptors, and phenolic and headspace composition upon treatment of oils obtained using novel process enhancement interventions, and their combination in an industrial plant is examined. Standard parameters are within the international specifications. The Control and MW process provide similar phenolic composition but a post MS intervention significantly increased total phenolic content, and decrease total C5 and C6 aldehydes in the MW treated paste. These results encourage further developments for a combined continuous MW and megasonic conditioning technology to fasten the olive oil extraction, to enhance yields, and total phenolic content. Practical Applications: Microwave and megasounds are two technologies easily implementable on industrial olive oil extraction plant. They permit to simplify the entire plant and could replace totally the malaxers section. This new technology allows having a uniform paste treatment in continuous mode, enhancing the olive oil quality.