Triglycerides, fatty

As noted earlier, natural alcohols are produced from coconut oil and tallow as well as some other fats and oils—palm kernel oil, palm oil, sperm whale oil, etc. Most of these natural oils actually consist of fatty triglycerides, i.e., glycerol esterified by three molecules of fatty acid. There is very little free alcohol present in these materials, and the alcohols are derived from the fatty acid moiety of the triglyceride by reduction. 

Hartop, P.J. and Prottey, C., Changes in transepidermal water loss and the composition of epidermal lecithin after applications of pure fatty triglycerides to the skin of essential fatty acid-deficient rats, Br. J. Dermatol., 95, 255, 1976. 

Glycerin can be prepared from propylene (via ECH) or as a byproduct from fat and oil hydrolysis of the soap industry. Before 1949 all glycerin was obtained from hydrolysis of fatty triglycerides. In the past 50 years, the synthetic glycerin is to serve the portion of demand not satisfied by natural glycerin. In 1998, the U.S. production for natural versus synthetic is about 2.4 1. The diagram of different routes for the manufacture of glycerin is in Fig. 10.26. 

Eats and oils from a number of animal and vegetable sources are the feedstocks for the manufacture of natural higher alcohols. These materials consist of triglycerides glycerol esterified with three moles of a fatty acid. The alcohol is manufactured by reduction of the fatty acid functional group. A small amount of natural alcohol is also obtained commercially by saponification of natural wax esters of the higher alcohols, such as wool grease. 

Fats and oils are one of the oldest classes of chemical compounds used by humans. Animal fats were prized for edibiUty, candles, lamp oils, and conversion to soap. Fats and oils are composed primarily of triglycerides (1), esters of glycerol and fatty acids. However, some oils such as sperm whale (1), jojoba (2), and orange roughy (3) are largely composed of wax esters (2). Waxes (qv) are esters of fatty acids with long-chain aUphatic alcohols, sterols, tocopherols, or similar materials. 

Fatty acids derived from animal and vegetable sources generally contain an even number of carbon atoms siace they are biochemically derived by condensation of two carbon units through acetyl or malonyl coenzyme A. However, odd-numbered and branched fatty acid chains are observed ia small concentrations ia natural triglycerides, particularly mminant animal fats through propionyl and methylmalonyl coenzyme respectively. The glycerol backbone is derived by biospeciftc reduction of dihydroxyacetone. 

Table 1. Fatty Acids Found in Naturally Occurring Triglycerides...

Fig. 6. Melting points of mono-, di-, and triglycerides, where H is fatty acid I, triglyceride 1,3-diglyceride and, 1-monoglyceride.

Infrared spectra of fats and oils are similar regardless of their composition. The principal absorption seen is the carbonyl stretching peak which is virtually identical for all triglyceride oils. The most common appHcation of infrared spectroscopy is the determination of trans fatty acids occurring in a partially hydrogenated fat (58,59). Absorption at 965 - 975 cm is unique to the trans functionaHty. Near infrared spectroscopy has been utilized for simultaneous quantitation of fat, protein, and moisture in grain samples (60). The technique has also been reported to be useful for instmmental determination of iodine value (61). 

Free Fatty Acid and Saponification Value. High concentrations of free fatty acid are undesirable in cmde triglyceride oils because they... 

Esters. The mono- and diesters of glycerol and fatty acids occur naturally ia fats that have become partially hydrolyzed. The triglycerides are primary components of aaturaHy occurring fats and fatty oils. 

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