Fatty acids in fats and oils

Fatty acids in oils and fats are found esterified to glycerol. Glycerol (1,2,3-trihy-droxypropane) is a prochiral molecule. It has a plane of symmetry, but if the primary hydroxyls are esterified to different groups, the resulting molecule is chiral and exists as two enantiomers. The stereospecific numbering system is used to... 

The stability of canola oil is limited mostly by the presence of linolenic acid, chlorophyll, and its decomposition products and other minor components with high chemical reactivity, such as trace amounts of fatty acids with more than three double bonds. These highly unsaturated fatty acids can possibly be formed during refining and bleaching (52). The presence of 7% to 11% of linolenic acid in the acylglyce-rols of canola oil places it in a similar category with soybean oil with respect to flavor and oxidative stability. The deterioration of flavor as the result of auto -and photo-oxidation of unsaturated fatty acids in oils and fats is referred to as oxidative rancidity. 

Hehner number. The percentage of weight of water-insoluble fatty acids in oils and fats. 

CHEMICAL PROPERTIES noncombustible solid gradually absorbs carbon dioxide upon exposure to air reacts with hydrochloric acid to produce zinc chloride reacts with sulfuric acid to produce zinc sulfate, and it reacts with carbon monoxide or hydrogen to produce elemental zinc reacts lowly with fatty acids in oils and fats to produce lumpy masses of zinc oleate, stearate, etc. forms cement-like products when mixed with a strong solution of zinc chloride or with phosphoric acid, owing to the formation of oxy-salts hydrogen peroxide is produced when ointments containing zinc oxide and water are melted and exposed to UV light FP (NA) LFL/UFL (NA) AT (NA) HC (NA) HF (-350.5 kJ/mol crystal at 25°C) pH (6.95 American process zinc oxide, 7.37 French process zinc oxide). 

Christy, A.A., Egeberg, P.K., and Ostensen, E.T., Simultaneous quantitative determination of isolated trans fatty acids and conjugated linoleic acids in oils and fats by chemometric analysis of the infrared profiles, Vib. Spectrosc., 33, 37-48, 2003. 

Fats and oils usually contain fatty acids in their free form as a result of spontaneous hydrolysis of the parent TG compounds. These free fatty acids (FFAs) are usually linear molecules with 4—24 carbon atoms that may be saturated or unsaturated with typically 1-3 C=C double bonds. Other compounds, such as pigments, waxes, sterols, glycolipids, lipoproteins, hydrocarbons, long chain alcohols, carbohydrates and vitamins (E, A and D), can also be found in oils and fats in minor concentrations. 

Saturated—the state in which all available valence bonds of an atom, especially carbon, are attached to other atoms. The straight-chain alkyls (paraffins) are typical saturated compounds. Several fatty acids found in oils and fats are listed in Table 1. Where no double- or tnple-bonds are available, such compounds cannot be hydrogenated because diere are no places for attaching additional hydrogen atoms. 

This method permits the direct determination of TBARS in oils and fats without preliminary isolation of secondary oxidation products. This protocol is applicable to animal and vegetable fats and oils, fatty acids and their esters, partial glycol esters, and similar materials (AOCS, 1998). 

Fatty Acids and Fatty Alcohols Fatty acids are traditionally meant as aliphatic unbranched monocarboxylic acids, either saturated or unsaturated, but with a chain length of 4 to 28 carbon atoms. Sometimes even shorter acyclic aliphatic carboxylic acids like acetic acid are named fatty acids, although they are not found in oils and fats [19]. 

Free Fatty Acids in Crude and Refined Fats and Oils (FFA) (Ca 5a-40) determines FFA, as oleic acid, by ethanolic sodium hydroxide titration. 

The configuration of the double bond in naturally occurring fatty acids, present in oils and fats, is predominantly in the cis form. Isomerization can occur if oils and fats are heated at temperatures above 100°C in the presence of bleaching earths or catalysts such as nickel, selenium, sulfur, or iodine. 

Yu Z, Singh B, Rizvi SSH, Zollewg JA. Solubilities of fatty acids, fatty acid esters, triglycerides, and fats and oils in supercritical carbon dioxide. J Supercrit Fluids 1994 7 51. 

Table 26.2 Approximate Percentage of Fatty Acids in Some Common Fats and Oils...

Dobson, G., Cyclic Fatty Acids Quabtative and Quantitative Analysis, in Lipid Analysis in Oils and Fats, edited by. R.J. Hamilton, Blackie A P, London, 1998, pp.136-180. 

The paraffinic acids are known as the fatty acids, because the larger molecules of the series occur in oils and fats. The simpler members of the series are ... 

In the same year these recommendations were followed by a news release that placed restrictions in the content of C22 monoenoic fatty acids in processed edible fats and oils. In the news release the minister of Health and Welfare announced that, "the maximum content of C22 monoenoic fatty acids in processed edible fats will be restricted to 5% of the total fatty acids present as of December 1, 1973."... 

Composition of oil/fat. To study the composition of oil/fat it is essential to test the purity of an oil/ fat for adulteration, accidentally or voluntarily. The specific fatty acid in fat can be determined by GC by preparing methyl esters with sodium methoxide. Mass spectrometry coupled to GC (GC-MS) is the most powerful tool for identification of fatty acids separated by GC. Free fatty acids in oil (index of rancidity) can be determined by titration against standard alkali. Infrared (IR) spectroscopy, Raman spectroscopy, and ultraviolet (UV) spectroscopy (200—400 nm) are used to detect isomers (trans and cis) of unsaturated fatty acids and conjugated double bonds. It is important to study saponification value (depict fatty acid chain length), iodine value (give the degree of unsaturation), and hydroxyl value (free fatty acids present in fats). 

Itabashi, Y., Myher, J. J. and Kuksis, A. (1993) Determination of positional distribution of short-chain fatty acids in bovine milk fat on chiral columns. J. Am. Oil Chem. Soc., 70, 177-81. 

In chemical terms fatty oils and fats are esters of glycerol and fatty acids. Arachidis oil and Miglyol 812 (medium chain triglycerides) are examples of often used fatty oUs. In contrast to hydrocarbons they are biodegradable. They hardly absorb water but cover the skin less extensive than the hydrocarbons. Fatty oils and fats reduce the viscosity of semisolid cutaneous preparations and improve their spread-ability. They are used in soft pastes for example. 

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