Microwave-Assisted Transesterification of Cooking Oils and GC-MS Determination of Their Fatty Acid Constituents: A Research-Based Integrated Lab Experiment

摘要

An increased public knowledge of the health benefits of unsaturated fats has resulted in a surge of different cooking oils. Intense advertising of various oil brands claiming to provide the best dietary recommendations often leaves buyers unclear of what their best choices are. Herein, we describe a research-based project for upper-level undergraduate students, where they can use interdisciplinary concepts in organic chemistry, biochemistry, analytical chemistry, and instrumental analysis to integrate them in a nutrition lab. The experiment was tested over two years in the Instrumental Analysis class, where each student analyzed a liquid oil used for cooking or salad dressings. Ten cooking oils were selected: sunflower, safflower, avocado, sesame, peanut, corn, canola, grapeseed, soybean, and a mixture of sunflower and coconut oils. Six different olive oil products were also compared according to their country of origin, fertilizer used (organic or regular), and type of oil (extra virgin, extra light, 100% pure). The fatty acids (FAs) were first derivatized to their volatile methyl esters (FAMEs) using a microwave-assisted, base-mediated transesterification reaction and then quantified by GC-MS. After pooling the class data, students were exposed to the practical aspects of food analysis while gaining more understanding of their dietary choices.