Fatty acid,tocopherol composition and the antioxidant activity of the lipid extract from the sorghum grains growing in Algeria

Abstract

The aim of this study was to examine the fatty acid and tocopherol composition and the antioxidant activity of the lipids fractions of two varieties of sorghum grains grown in Algeria. The results revealed that the total oil contents in the sorghum ranged from 11 to 13%. Gas chromatography analysis of the oils revealed that the dominant fatty acids found are palmitic, oleic and linoleic. The oils contain a significant amount of unsaturated fatty acids (>84%). Oils were also high in tocopherol, with a wide variation (between 174.82 and 325.33 mg/kg) but with δ-tocopherol predominating in the two oils. The lipid extracts were subjected to screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl, phosphomolybdenum complex and FRAP assays. In the first case, IC₅₀ values of the extracts were 15.4 and 22.6 mg/mL in the red and in the white sorghum, respectively. In the phosphomolybdenum complex and the FRAP assays the antioxidant capacity of the extracts ranged, respectively, between 0.21–0.13 μmol/g vitamin E equivalents and 0.030–0.027 mmol/g vitamin C equivalents. In the three systems, the antioxidant capacities of vitamin E and ascorbic acid were also determined in parallel experiments.