Effect of Environment on Fatty Acid Composition and Tocopherol Content in Soybean, Glycine max L Merrill

Abstract

Soybean is an important legume containing 20 % oil which is an important source of tocopherols. Tocopherols are an important dietary constituent with high antioxidant properties and serve as a first line of defense in human beings protecting membranes from lipid peroxidation. The objective of this study was to compare the fatty acid composition and tocopherols of twenty soybean genotypes grown under different environments. Averaged over twenty genotypes, the minimum value for palmitic, stearic and oleic acids was observed at Gurdaspur during July planting and maximum in June planting at Ludhiana whereas linoleic and linolenic acids showed the reverse trend. High performance liquid chromatographic analysis of tocopherol composition of soybean genotypes grown at two different locations and planting times revealed highest contents of total and γ-tocopherol in genotype ‘SEL-P’ and least concentration of total and different isomers of tocopherols in genotype ‘SL 793′. Linolenic acid was negatively correlated with γ, α and total tocopherol contents suggesting that lowering 18:3 levels may result in similar or higher tocopherols in a particular genotype. Genotypes ‘PK 1026′ and ‘SL 992′, due to their high oleic and low linolenic acid contents across both locations and planting times can be preferred in terms of their oil stability. Genotypes ‘SEL-P’ and ‘DS98-2′ with high total tocopherol content could be appropriate for food purposes because of high γ-tocopherol content. Studies suggested that it is possible to develop cultivars with better oil quality and tocopherols depending upon the need of the consumers.