Canola oil with high antioxidant content obtained by combining emerging technologies: microwave, ultrasound, and a green solvent

Abstract

In this work, the ultrasound‐assisted extraction (UAE) of canola oil from canola seeds pretreated with microwaves using ethanol 99% as solvent is studied. Different process parameters are evaluated, such as extraction time, temperature, solid:solvent ratio, and ultrasound amplitude, optimizing the process using response surface methodology. Under optimum conditions, the extraction time is decreased by up to 75% with respect to conventional extractions, obtaining an oil with a higher content of total tocopherols and canolol, and with oxidation indexes within the established standard limits. The addition of a microwave pretreatment to the UAE with ethanol 99% shows a synergic effect between both processes, improving the oil yield. The results obtained in this study show the potential of the use of UAE for the extraction of canola oil using a green solvent, reducing processing times, environmental pollution, and achieving an oil of high quality and antioxidant concentration. Practical Application: The industrial use of petroleum‐derived solvents such as hexane has problems concerning sustainability, environment, and safety. In recent years, the use of "green" solvents for the extraction of vegetable oils began to be studied; however, it is necessary to develop stages that allow improving the extraction process by increasing the yield, reducing the processing times, and optimizing the oil quality. In this sense, ultrasound allows to shorten the extraction times while microwave pretreatments applied to canola seeds generate an increase in the concentration of antioxidants in the oil, facilitating the implementation of a "green" process in the industrial production.