Olive oils contain fats



Comparison of Two Types of Gas Chromatography on Fatty Acids in Olive Oil

Adam Merrick, Berrien County Mathematics and Science Center, Berrien Springs, Michigan

Abstract

There are new techniques for gas chromatography, one of them being comprehensive 2-dimensional GC. This technology was applied to the study of fatty acid profiles of olive oil. The samples were taken from extra virgin olive oil. Samples were heated to find the difference in their fatty acid profiles before and after heating. The separation of peaks that the comprehensive 2-dimensional GC provided was able to bring forth additional information that would have gone unnoticed with a 1-dimensional GC.

Introduction

Olive oils contain fats. Fats are triglycerides which have the chemical structure as shown in Figure 1.

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Figure 1. Chemical structure of a triglyceride.

Triglycerides contain two components, glycerol and fatty acids. The chemical structure of glycerol is shown in Figure 2.

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Figure 2. Chemical structure of glycerol.

Fatty acids are carboxylic acids with a hydrocarbon chain varying in length between 12 and 24 carbons for olive oil. See Figure 3. [pic]

Figure 3. Chemical structure of fatty acid.

These hydrocarbon chains may have 0, 1 or more double bonds along this chain. Chains with no double bonds are called saturated. Chains with at least one bond are unsaturated. Specifically those with one double bond are called monounsaturated. Those with two or more are called polyunsaturated. In the case that a double bond occurs on the chain, it can orient itself in two ways. One way is called trans. The trans configuration retains the zigzag shape of the chain. Cis is the other possibility, causing the chain to bend or curve making it lose its straight structure. Figure 4 shows examples of a cis and trans fatty acid. [pic]

Figure 4. Chemical structures of cis and trans fatty acids.

One way of naming fatty acids is by calling it “C “ followed by the number of carbons in the chain, followed by a colon and the number of double bonds in the chain. An example using figure 4 would be C18:1 cis, or C18:1 trans.

Olive oil has the following fatty acids present primarily within triglycerides: lauric acid (C12:0) not present in discernible amounts, myristic acid (C14:0) ................
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