Thesis Abstract

Thesis Overview

<p> 1.1 Vegetable oil<br>A vegetable oil is a triglyceride extracted from a plant. Such oils have been part of human culture for millennia. The term “vegetable oil” can be narrowly defined as referring only to substances that are liquid at room temperature, or broadly defined without regard to a substance’s state of matter at a given temperature. For this reason, vegetable oils that are solid at room temperature are sometimes called vegetable fats. Vegetable oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure. Although many plant parts may yield oil, in commercial practice, oil is extracted primarily from seeds.<br><strong>1.2 Project ion of Vegetable Oils</strong><br>To produce vegetable oils, the oil first needs to be removed from the oil-bearing plant components, typically seeds. This can be done via mechanical extraction using an oil mill or chemical extraction using a solvent. The extracted oil can then be purified and, if required, refined or chemically altered.<br><strong>1.2.1 Mechanical extraction</strong><br>Oils can also be removed via mechanical extraction, termed “crushing” or “pressing.” This method is typically used to produce the more traditional oils (e.g., olive, coconut etc.), and it is preferred by most health food customers in the United States and in Europe. There are several different types of mechanical extraction: expeller-pressing extraction is common, though the screw press, ram press, and Ghani (powered mortar and pestle) are also used. Oil seed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive; the Ghani is primarily used in India.<br><strong>1.2.2 Solvent extraction</strong><br>The processing of vegetable oil in commercial applications is commonly done by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived hexane. This technique is used for most of the “newer” industrial oils such as soybean and corn oils. Supercritical carbon dioxide can be used as a non-toxic alternative to other solvents.<br><strong>1.2.3 Sparging</strong><br>In the processing of edible oils, the oil is heated under vacuum to near the smoke point, and water is introduced at the bottom of the oil. The water immediately is converted to steam, which bubbles through the oil, carrying with it any chemicals which are water-soluble. The steam sparging removes impurities that can impart unwanted flavors and odors to the oil…… <br></p>