Saturated fatty acids, determination

Properties are furthermore determined by the nature of the organic acid, the type of metal and its concentration, the presence of solvent and additives, and the method of manufacture. Higher melting points are characteristics of soaps made of high molecular-weight, straight-chain, saturated fatty acids. Branched-chain unsaturated fatty acids form soaps with lower melting points. Table 1 Hsts the properties of some soHd metal soaps. 

The specific behaviour of unsaturated fatty acids under oxidation is determined by the position and the number of double bonds in the fatty acid molecule. The stepwise oxidation of an unsaturated acid to the position of a double bond in it proceeds in a manner similar to that of saturated acid oxidation. If the double bond retains the same configuration (trans-configuration) and position (A2,3) as those of the enoyl-CoA, which is produced during the oxidation of saturated fatty acids, the subsequent oxidation proceeds via conventional route. Otherwise, the oxidation reaction proceeds with the involvement of an accessory enzyme, A3,4-CiS-A2,3jrans-enoyl-CoA isomerase this facilitates the translocation of the double bond to an appropriate position and alters the double-bond configuration from cis to trans. 

The physical and chemical properties of individual oils and fats are determined by the nature and proportions of fatty acids that enter into the triglycerides composition. Animal and dairy fat like plant oils are dominated by triacylglycerols, with steroids present as minor components, cholesterol and its esters being the most significant. The triacylglycerols of animal fats differ from plant oils since they contain more of the saturated fatty acids and consequently are solid at room temperature. 

BETA derivatives of C9-C22 saturated fatty acids, as well as the Cig unsaturated acids, oleic and elaidic, were prepared and evaluated in the previous publication (11). Hydrophobicity determination, via contact angle measurements, proved to be nondiscriminatory and, therefore, a more meaningful test, the sand penetration test was devised. 

This finding has been replicated several times in clinical studies. Let me cite one example. In a careful metabolic study carried out in 1990, Mensink and Katan determined the plasma LDL/HDL ratio when 10% of the energy from oleic acid was replaced in the diet by either the corresponding trans fat or the corresponding saturated fatty acid, stearic acid. The resulting LDL/HDL ratios were 2.02 on the oleic acid diet, 2.34 on the stearic acid diet, and 2.58 on the trans fatty acid diet. This is one more example of the impact of small structural changes in molecules on their biological properties. 

Both maternal and infant factors determine the final amount of drug present in the nursing child s body at any particular time. Variations in the daily amount of milk formed within the breast (e.g., changes in blood flow to the breast) as well as alterations in breast mUk pH wUl affect the total amount of drug found in mUk. In addition, composition of the milk will be affected by the maternal diet for example, a high-carbohydrate diet will increase the content of saturated fatty acids in milk. 

Potatoes are not regarded as an important source of lipids, because the lipid content of the tuber is very low, ranging from 0.2 to 2 g (1.2 g on average) per kg on a fresh weight basis (OECD, 2002). The flesh of boiled potato cooked in skin without salt contains about 0.1 g total lipids, 0.03 g total saturated fatty acids, 0.002 g total monounsaturated fatty acids, and 0.043 g total polyunsaturated fatty acids per 100 g (USDA, 2007). The Adequate Intake determined for the essential n-6 and n-3 polyunsaturated fatty acids is for adults 11-17 and l.l-1.6g per day, respectively (Food and Nutrition Board, 2005). 

An accurate investigation of these problems was, however, only possible after the development of reliable methods of analysis. Particularly Bertram s method55 for the determination of saturated fatty acids should be mentioned. Van Vlodrop70 proved its usefulness for the study of the hydrogenation of several fatty acid esters (oleic, linoleic, elaeostearic). 

Experimental 1 T, dietary fats, both quantity and quality, play important roles in the genesis of cancers of many organs (18,19). Earlier, we demonstrated that a high fat CD diet is a more efficient liver tumor promoter than the diet with a low fat content (5). The proportion of saturated and polyunsaturated fatty acids in a CD diet is an important determining factor for the severity of the diet-induced fatty liver (20,21). Saturated fatty acids containing 14 to 18 carbons in the diet appeared to increase the deposition of fat in the liver more so than unsaturated fatty acids (22). It became of considerable interest to determine whether and how changing the quality of fat in a CD diet modifies the promoting efficacy of the diet. 

In the SC lipids form two crystalline lamellar phases.27 The mixture of both phases produces the optimal barrier to water loss from SC. The balance between the liquid crystalline and the solid crystal phases is determined by the degree of fatty acid unsaturation, the amount of water, and probably by other yet undiscovered factors. A pure liquid crystal system, produced by an all-unsaturated fatty acid mixture, allows a rapid water loss through the bilayers with a moderate barrier action. The solid system produced with an all-saturated fatty acid mixture causes an extreme water loss due to breaks in the solid crystal phase.6,23 Studies with mixtures prepared with isolated ceramides revealed that cholesterol and ceramides are very important for the formation of the lamellar phases, and the presence of ceramide 1 is crucial for the formation of the long-periodicity phase.27 The occurrence of dry skin associated with cold, dry weather for example, may result from an extensive, elevated level of skin lipids in the solid state. Therefore, a material that maintains a higher proportion of lipid in the liquid crystalline state may be an effective moisturizer.6... 

UCOME = used cooking oil methyl esters B/S = biodiesel/solvent mass ratio TBatii = bath coolant temperature (final step) Yield = mass ratio liquid fraction to starting material Sats = total concentration of saturated fatty acid methyl esters in liquid fraction (determined by GC). See Tables 1.2 and 1.3 for other abbreviations. 

Determining the threshold value is difficult because subthreshold levels of one compound may affect the threshold levels of another. Also, the flavor quality of a compound may be different at threshold level and at suprathreshold levels. The total range of perception can be divided into units that represent the smallest additional amount that can be perceived. This amount is called just noticeable difference (JND). The whole intensity scale of odor perception covers about 25 JNDs this is similar to the number of JNDs that comprise the scale of taste intensity. Flavor thresholds for some compounds depend on the medium in which the compound is dispersed or dissolved. Patton (1964) found large differences in the threshold values of saturated fatty acids dissolved in water and in oil. 

Cell membrane fluidity is determined by its hpid composition. The cell membrane is rendered more rigid if increased amounts of saturated fatty acids and cholesterol are incorporated into the membrane phospholipids. In contrast, increased incorporation of unsaturated fatty acids into the membrane will make it more fluid. This increase in membrane fluidity has been shown to increase the number of receptors and their affinity to their respective hormones or growth factors. For instance, an increase in the rigidity of the cell membrane reduces the number of insulin receptors and their affinity to insulin that, in turn, could cause insulin resistance. Alternatively, an increase in cell membrane fluidity because of an increase in the unsaturated fatty acid content in the membrane phosphohpids increases the number of insulin receptors and their affinity to insuhn and, thus, decreases insulin resistance (35 2). 

In contrast to the high proportion of saturated fatty acids in the sn-2 position of lard, the tallows contain predominantly an unsaturated fatty acid (about 60% relative abundance), generally oleic (18 1), in this position. This has been exploited to develop a method to detect the adulteration of beef fat with lard (32). This involves hrst the isolation of the acylglycerols containing one saturated and two unsaturated fatty acids, followed by determination of the fatty acid population at the sn-2 position of this fraction. The sensitivity is reported to be sufficient to detect the presence of 1% lard in the tallow. 

Cottonseed Oil Fatty Acid Composition. The specific fatty acid profile of the triglycerides in cottonseed is dependent on the variety of cotton grown, growing conditions such as temperature and rainfall, and the analytical method used to determine the profile. Table 5 summarizes the fatty acid composition observations of several research and commercial groups. Cottonseed oil is typical of the oleic-linoleic group of vegetable oils, because those two fatty acids comprise almost 75% of the total fatty acids. Although oleic acid makes up 22% and linoleic makes up 52%, less than 1 % linolenic acid is present. Palmitic fatty acid makes up about 24% of the fatty acids. Minor amounts of other saturated fatty acids are also found. 

Bailey (23) noted that the composition of American cottonseed oils will rarely fall outside of these limits 23-28% total saturated fatty acids, 22-28% oleic acid, and 44-53% linoleic acid. The Food and Agriculture Organization of the World Health Organization (FAO/WHO) has determined a range of fatty acid contents for commercial fats and oils. The acceptable range of fatty acids prescribed by Codex in 1997 for cottonseed oil is shown in Table 6 (77). 

Solid Fat Index. This analysis has become the most important criterion for the melting behavior and crystalline structure of fats and oils products. It determines the proportion of solid and liquid materials at a given temperature. The solid fat index (SFI) analysis is an empirical measure of the solid fat content. It is calculated from the specific volume at various temperatures using a dilatometric scale graduated in units of milliliters times 1000. Values for the solid contents are usually determined at 50°F, 70°F, 80°F, 92°F, and 104°F or 10°C, 21.1°C, 26.7°C, 33.3°C, and 40°C. Unlike the tropical oils, cottonseed and the other oleic- and lino-leic-classification oils do not contain any significant quantity of triglycerides made up of two or three saturated fatty acids therefore, the solid fat index at the lowest temperature usually measured would have minimal values. Natural cottonseed oil can have a solid fat index content at 50°F or 10°C but not at the higher temperature measurements. 

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