Abstract
To develop a method for detecting and estimating the quantity of adulterant linseed oil in rapeseed oil, samples of these oils collected from different sources were analysed, among other things, for fatty acid, sterol and tocopherol composition content. Each oil sample was mixed with the other in the following proportions : 100 : 0; 95 : 5; 90 : 10; 85 : 15; 80 : 20; 75 : 25; and 0 : 100. All mixtures thus obtained were analyzed in the same manner as that for individual content oils. The saponification and iodine values and refractive indices of the mixtures were also measured.
In the adulterated rapeseed oil samples, the stearic and linolenic acid content increased with that of linseed oil. Also, GLC analyses of sterol constituents of the linseed oil showed characteristic retention time (RT) which were also clearly observed for the oil mixtures.
These observations indicate that the proportions of adulterant linseed oil when mixed 5 to 10% with rapeseed oil can quite likely be detected. The analysis of tocopherol did not appear to facili-tate detection of linseed oil in any of the mixtures but the values of iodine, and butyro refracto-meter readings helped to indicate if linseed oil was present or not.
