Determination of Content of Linseed Oil in Edible Soybean Oil

A method for detecting and computing the quantity of adulterant linseed oil in soybean oil was developed by determining the fatty acid, sterol and tocopherol compositions of component oils and adulterated mixtures.In adulterated oil samples, a decrease in linoleic acid and increase in linolenic acid content were observed with increase in the amount of linseed oil. Analysis of sterol constituents of linseed oil showed a characteristic component having a retention time of 78 minutes which was also clearly observed for the oil mixtures. A remarkable decrease in stigmasterol content was observed with increase in linseed oil. Analysis of tocopherols showed the linseed oil to be richer than soybean oil in β-tocopherol content and there to be a significant increase in β-tocopherol content with increase in linseed oil.These findings provide sufficient evidence of the presence of adulterant linseed oil in soybean oil. The limit of detection was as low as 510% linseed oil in soybean oil.