Partially hydrogenated vegetable oil

Small amounts of trans-unsamrated fatty acids are found in ruminant fat (eg, butter fat has 2-7%), where they arise from the action of microorganisms in the rumen, but the main source in the human diet is from partially hydrogenated vegetable oils (eg, margarine). Trans fatty acids compete with essential fatty acids and may exacerbate essential fatty acid deficiency. Moreover, they are strucmrally similar to samrated fatty acids (Chapter 14) and have comparable effects in the promotion of hypercholesterolemia and atherosclerosis (Chapter 26). 

Unsaturated fats, as noted in Section 13.3, tend to be liquids at room temperature. They can be transformed to a more solid consistency, however, by hydrogenation, a chemical process in which hydrogen atoms are added to carbon—carbon double bonds. Mix a partially hydrogenated vegetable oil with yellow food coloring, a little salt, and the organic compound butyric acid for flavor, and you have margarine, which become popular around the time of World War II as an alternative to butter. Many food products, such as chocolate bars, contain partially... 

As more of the double bonds are saturated, the melting point of the product increases. The degree of hydrogenation is carefully controlled to produce a product with just the right melting point, a partially hydrogenated vegetable oil. 

Q Explain how unsaturations affect the properties of fats and oils. Compare the properties of saturated fats with those of polyunsaturated oils and partially hydrogenated vegetable oils. 

The long-term health effects of eating partially hydrogenated vegetable oils concern some nutritionists because many unnatural fatty acids are produced. Consider the partial hydrogenation of linolenic acid by the addition of one or two equivalents of hydrogen. Show how this partial hydrogenation can produce at least three different fatty acids we have not seen before. 

Peanut butter is a common consumer product that contains partially hydrogenated vegetable oil. 

Many processed foods, such as peanut butter, margarine, and some brands of crackers, contain partially hydrogenated vegetable oils. These oils are produced by hydrogenating the long hydrocarbon chains of triacylglycerols. 

Perflex. [Van Den Beigh FOods] Partially hydrogenated vegetable oil emul-sifi shmtening for cakes, yeast-leav-enedprods. 

Reflect and Apply Suggest a reason why partially hydrogenated vegetable oils are used so extensively in packaged foods. 

Partially hydrogenated vegetable oils have the desired consistency for many foods, such as oleomargarine and components of TV dinners. 

Many of the double bonds have been saturated. Crisco contains partially hydrogenated vegetable oils. ... 

Partially hydrogenated vegetable oils were developed in part to help displace highly saturated animal fats used in frying, baking, and spreads. It is important not to complete the reaction and totally saturate all the double bonds. If this is done, the product is hard and waxy—not the smooth, creamy product desired by consumers. Equation 8.4 gives an example in which some of the double bonds react, showing one of the possible products. 

Chem. Descrip. Partially hydrogenated vegetable oils (palm kernel, coconut, and palm)... 

---