Physicochemical characteristics and oxidative stability of Egyptian corn germ oil produced by aqueous enzymatic extraction

Abstract

The physicochemical properties and the oxidative stability of Egyptian corn germ oil produced by aqueous enzymatic extraction using fungal cellulase, bacterial and bovine proteases, either individually or in combination were compared to that extracted by hexane. The optimized conditions of the new bovine protease for maximum oil yield were: 0.1% enzyme, pH 7.5 and 1h incubation time versus 0.6%, 0.63% enzyme, pH 4, 8.2 and 4, 2h incubation for fungal cellulase and bacterial protease, respectively. The higher oil yield was obtained by combining cellulase with bacterial protease (62.38%) or with bovine protease (51.94%) relative to hexane extraction (100%). The refractive index, iodine, saponification and peroxide values, DPPH scavenging activity, as well as fatty acids composition of enzymes and solvent-extracted oils were comparable. The acid value and color index of the enzyme-extracted oils were better than that produced by hexane, indicating that enzymes could be applied in the production of eco-friendly corn oil.