Gas chromatographic characterization of vegetable oil deodorization distillate

Because of its complex nature, the analysis of deodorizer distillate is a c hallenging problem. Deodorizer distillate obtained from the deodorization p rocess of vegetable oils consists of many components including free fatty a cids, tocopherols, sterols, squalene and neutral oil. A gas chromatographic method for the analysis of deodorizer distillate without saponification of the sample is described. After a concise sample preparation including deri vatization and silylation, distillate samples were injected on column at 60 degreesC followed by a gradual increase of the oven temperature towards 34 0 degreesC. The temperature profile of the oven was optimized in order to o btain a baseline separation of the different distillate components includin g free fatty acids, tocopherols, sterols, squalene and neutral oil. Good re coveries for delta -tocopherol, alpha -tocopherol, stigmasterol and cholest eryl palmitate of 97, 94.4, 95.6 and 92%, respectively were obtained. Repea tability of the described gas chromatographic method was evaluated by analy zing five replicates of a soybean distillate. Tocopherols and sterols had l ow relative standard deviations ranging between 1.67 and 2.25%. Squalene, m ono- and diacylglycerides had higher relative standard deviations ranging b etween 3.33 and 4.12%. Several industrial deodorizer distillates obtained f rom chemical and physical refining of corn, canola, sunflower and soybean h ave been analyzed for their composition. (C) 2001 Elsevier Science B.V. All rights reserved.