Supercritical fluid extraction of corn germ oil: Study of the influence of process parameters on the extraction yield and oil quality

The supercritical fluid extraction of corn germ oil has been studied in this work. Extractions were carried out at different pressure, temperature and flow rate to analyze the influence of these variables on the extraction kinetics and the oil quality obtained. Extraction curves are initially linear with a slope close to the oil solubility value in supercritical CO2. Based on these results a mathematical model was successfully applied to describe the extraction curves. Characterization of supercritical crude corn oil was performed by determining some physical parameters such as refraction index, density and color. Additionally, the fatty acid composition, neutral lipids, the content of tocopherols, acid index, peroxide value, antioxidant capacity and the oxidative stability were determined in the corn oil extracted. Fatty acid composition was compared with that for crude germ oil and no significant differences between the oils extracted by both methods were found. Oxidative stability test using the Rancimat showed that supercritical CO2 extracted corn oil is less protected against oxidation than n-hexane extracted oils.

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► Supercritical fluid extraction of corn germ oil at different pressures, temperatures and flow rates has been carried out.
► Extraction process may be controlled by the solubility of the oil in SC-CO2 in the first stages of the extraction.
► When increasing extraction temperature in the range 40–85 °C, oils with higher tocopherol content and higher antioxidant activity are obtained.
► Fractionation improves the oil stability against oxidation.