Determination of the quality characteristics of corn oil obtained by different extraction methods

The objective of this study was to evaluate crude oil yields, fatty acid and triglyceride compositions and sterol and tocopherol contents of the corn oils obtained from corn germ by cold pressing and solvent extraction. The properties of corn oils obtained by both methods were then compared. The moisture and crude protein contents of the germs (embryos) used in the corn oil production were determined to be 6.3 and 20.12%, respectively. The crude oil yield was calculated as 31.29% for solvent extraction and 25.72% for cold pressing. Refractive indices of corn oils were found to be 1.4662-1.4664 while iodine values were 122.61 and 123.58 on average for solvent-extracted and cold-pressed corn oils, respectively. The main fatty acids determined in the corn oils were linoleic, oleic and palmitic acids. The average linoleic, oleic and palmitic acid contents of the corn oils were found to be in the range from 51.22 to 51.80%, from 31.67 to 31.97% and from 12.43 to 12.52%, respectively. The main triglyceride structures present in the corn oils were determined to be OLL (21.05-21.28%), LLL (16.46-16.66%), OOL+LnPP (14.26-14.33%) and PLL (13.76-13.84%). Theoretical ECN42 values were evalutaed as 14.29 and 14.32 for solvent-extracted and cold-pressed corn oils, respectively. The major sterols determined in the corn oils were β-sitosterol (65%), campesterol (29%), stigmasterol (6%) and sitostanol (4%).