Polyunsaturated fat

Polybutadiene and polyunsaturated fats, which contain aHyUc hydrogen atoms, oxidize more readily than polypropylene, which contains tertiary hydrogen atoms. A linear hydrocarbon such as polyethylene, which has secondary hydrogens, is the most stable of these substrates. 

Figure 7.8 Catalytic hydrogenation of polyunsaturated fats leads to saturated products, along with a small amount of isomerized trans fats.

We hear a lot these days about the relationships between saturated fats, cholesterol, and heart disease. What are the facts It s well established that a diet rich in saturated animal fats often leads to an increase in blood serum cholesterol, particularly in sedentary, overweight people. Conversely, a diet-lower in saturated fats and higher in polyunsaturated fats leads to a lower serum cholesterol level. Studies have shown that a serum cholesterol level greater than 240 mg/dL (a desirable value is <200 mg/dL) is correlated with an increased incidence of coronary artery disease, in which cholesterol deposits build up on the inner walls of coronary arteries, blocking the flow of blood to the heart muscles. 

Polysaccharide, 617,619 Polythiophene, 93 Polyunsaturated fats, 604 Polyvinyl chloride (PVC), 612-613 Positive integer, 643... 

Saturated fats are usually solid, while unsaturated fats or polyunsaturated fats (which have two or more double bonds) are usually liquid at room temperature. 

Trilinolein is a polyunsaturated fat. This type of fat is an antioxidant that has been linked to a number of potential cardiovascular health benefits. It is found in seed oils such as safflower oil and linseed oil. 

Polyunsaturated fats can combine easily with oxygen at the points where there is a double bond between two carbon atoms. This is why they make good antioxidants they combine with the oxygen free radicals so they don t damage other molecules. It is also how oils harden, and is thus important to painters. Oil paints made with linseed oil are almost three-quarters trilinolein. They dry to form a tough plastic film that incorporates the pigments and holds them onto the surface to be painted. 

Gonjugation of polyunsaturated fats Methyl linoleate with tris(triphenylphosphine) chlororhodium. J.Am. Oil Chem. Soc., 48, 21-24. 

Matrix Components The term matrix component refers to the constituents in the material aside from those being determined, which are denoted as analyte. Clearly, what is a matrix component to one analyst may be an analyte to another. Thus, in one hand for the case of analyses for elemental content, components such as dietary fibre, ash, protein, fat, and carbohydrate are classified as matrix components and are used to define the nature of the material. On the other hand, reference values are required to monitor the quality of determinations of these nutritionally significant matrix components. Hence, there is a challenging immediate need for certified values for dietary fibre, ash, protein, fat, and carbohydrate. Concomitantly, these values must be accompanied by scientifically sound definitions (e.g. total soluble dietary fibre, total sulpha-ted ash, total unsaturated fat, polyunsaturated fat, individual lipids, simple sugars, and complex carbohydrates). 

In a saturated fatty acid, only single bonds are found between carbon atoms. The term saturated indicates that the carbon atoms of the chain contain all the hydrogen atoms that can be attached. Saturated fats contain only saturated fatty acid chains. A fatty acid with one or more double bonds in the chain is said to be unsaturated, that is, more hydrogen atoms can be attached. Unsaturated fats contain one double bond in the fatty acid chain. Polyunsaturated fats contain several double bonds. 

Linoleic acid is a polyunsaturated fatty acid (compound containing two or more double bonds) occurs as an ester in polyunsaturated fats. 

Polyunsaturated fats occur widely in the fats and oils that are components of our diet and are widespread in the tissues of the body where they perform numerous vital functions. 

Saturated fats were found to elevate serum cholesterol levels while polyunsaturated fats reduce them. This led to advice to consume less saturated fats and more polyunsaturated fats. 

However, if declarations are made about polyunsaturates, monounsat-urates or cholesterol the amount of saturates must also be given. Here, science has moved on from the time when saturated fats were the fats to avoid to advice to avoid trans fatty acids and to prefer monounsaturated fat to polyunsaturated fats. 

Oxidative rancidity is not necessarily a problem unless a polyunsaturated fat such as sunflower oil has been used. Where such a fat is used oxidative rancidity can occur and, as autoxidation occurs where the reaction becomes self-catalysing as oxygen free radicals react, some very unpleasant tastes can appear very quickly. In general, the effect of oxidation on biscuits at the end of their shelf life is that a cardboard taste starts to appear. 

Mean urine and fecal losses of calcium of subjects while receiving the three test fats are shown on Table II. Apparent calcium absorptions and calcium balances were calculated from this data. Mean fecal calcium losses when safflower oil, soybean oil and apricot kernal oil were fed were 460, 500 and 520 mg/day. With a probability of only P<0.10, these difference were not statistically significant although a strong trend toward increased fecal calcium losses with degree of saturatedness of the dietary fat was shown. Thus, a trend toward increase in calcium absorption with more polyunsaturated fats was illustrated. Coupled with changes in... 

Significantly improve keeping qualities of polyunsaturated fats and oils. 

Several studies have shown that low-fat or high-polyunsaturated-fat diets have no substantial effect on Lp(a) levels (M25). 

Approximately 60% of the dry weight of the brain is fat, a considerable proportion of which is polyunsaturated fatty acids that are present in plasma membranes. It would not be surprising if replacement of the unsaturated acids by the saturated fatly acids in membrane structure due to a dietary deficiency of polyunsaturated fatty acids played some part in development of mental illness. Indeed, it has been found that supplementation of a normal diet with polyunsaturated fatly acids can improve some mental disorder (see chapter 11). 

Sixty to eighty-five percent of the fatty acids in fishery products are either monounsaturated or polyunsaturated. Polyunsaturated fats have been shown to reduce blood cholesterol levels and the same phenomenon exists for fish oils. Epidemiological studies of the Greenland Eskimos show their diet to be high in marine oils and the populaticxi has correspcMidingly low serum cholesterol values (6) (7). 

Naturally occurring examples have fatty acids with an even number of carbon atoms, usually 10 to 20 without any branches. Double bonds are only present as the cis isomer. At least one double bond is present in an unsaturated fat multiple double bonds are present in a polyunsaturated fat. 

You can hydrogenate some of the double bonds in any polyunsaturated fat. Hydrogenation, whether complete or partial, results in an increase in the melting point, a fact that makes it possible to convert a liquid oil to a solid fat. (Note that partial hydrogenation may convert some of the cis double bonds into tram double bonds, thereby producing a trans fat.)... 

All Americans (except children younger than 2 years of age) should adopt a diet that reduces total dietary fat, decreases intake of saturated fat, increases intake of polyunsaturated fat, and reduces daily cholesterol intake to no more than 250 to 300 mg. 

Schouten, J. A., A. C. Beynen, C. Mulder, and H. F. Hoitsma. The effect of dietary saturated fat versus polyunsaturated fat on serum cholesterol and phospholipid concentrations in rabbits with partial ileal bypass. ZErnahrung-swiss 1984 23(2) 136-142. 

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