Corn germ-bran oils extracted with alcoholic solvents: Extraction yield, oil composition and evaluation of protein solubility of defatted meal

Ethanol and isopropanol as solvents for vegetable oil extraction process have very attractive advantages including low toxicity, good operational security and high nutraceutical-extracting capability, useful in many vegetable substrates, besides they can be obtained from renewable sources. Therefore, the aim of this study was to evaluate the extraction of corn germ-bran oil with these alcohols and their aqueous solutions, at temperatures from 50 up to 80 degrees C. The results showed that the oil and carbohydrate extraction yields are influenced by the type and hydration level of the solvent and temperature, while this last variable has not shown influence on liquid holdup. In sequential extraction trials, aqueous ethanol allowed oil extraction yields of approximately 70%, while the other solvents reached 90%. Regarding nitrogen solubility index of the protein present in defatted meal, a decrease was observed after the oil extraction process, being more prominent for systems where aqueous solvents were used. From the results, it can be inferred that alcoholic solvents enable extracting corn oils with a typical fatty acid composition; aqueous ethanol leads the extraction of higher levels of tocopherols and tocotrienols (449 and 195 mg/kg, respectively) and absolute isopropanol has the best performance in the extraction of carotenoids (373 mg/kg). (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.