| The sensory qualities (colour), physicochemical and nutritional qualities (moisture and volatile matter contents, fatty acid composition, vitamin E isomer and phytosterol contents) and processing qualities (induction time, peroxide value, acid value and fatty acid proportional modes) of the solvent-extracted walnut oil and the cold-pressed walnut oil were determined. The correlation analysis of the quality indexes of the walnut oils was conducted. The results showed that the cold-pressed walnut oil had better processing quality with longer induction time(1.92 h), lower peroxide value (1.44 mmol/kg) and acid value (0.69 mgKOH/g), higher ratio of oleic acid to linoleic acid (0.33), and higher contents of oleic acid (19.97%) and unsaturated fatty acids (90.96%) than solvent-extracted walnut oil. Furthermore, colour and induction time were markedly positive correlated, while oleic acid and linoleic acid were significantly negative correlated (r=-0.944), and induction time was remarkably correlated with oleic acid, linoleic acid, monounsaturated fatty acids, polyunsaturated fatty acids and ratio of oleic acid to linoleic acid. |
