Free fatty adds

No discussion of the use of biotransfarmation in lipid chemistry would be complete without some mention of chemical transformation relating to fatty adds. Fatty adds are a major component of the lipid fraction of organisms. They are mainly found as components of triglycerides and phospholipids, although they may occur in smaller quantities as free fatty adds or as esters of other moieties. Fatty adds, either as free adds or as esters, are valuable commodities in the food and cosmetics industries. They may also serve as precursors of a variety of other compounds. 

Mixtures of triglycerides, triglycerides plus free fatty adds or triglycerides plus fatty acid alkyl esters are used as reactants in fat modification processes. These mixtures are exposed to lipases supported on macroporous particles in the presence of a small amount of water. Liquid substrates (oils) can be reacted without use of a solvent, but with solid reactants (fats) it is necessary to add a solvent to ensure that the reactants and products are completely dissolved in the organic phase. Various water immisdble solvents can be used, but hexane is preferred for commercial operation because this solvent is already used industrially for the processing of oils and fats. 

Figure 22-9. Regulation of ketogenesis. -(Dshow three crucial steps in the pathway of metabolism of free fatty adds (FFA) that determine the magnitude of ketogenesis. (CPT-I, carnitine palmitoyltransferase-l.)...

Free fatty adds in plasma are a major source of energy, particularly under marathon conditions and in prolonged starvation. 

Release of free fatty adds from storage... 

The naturally occurring fatty acids are carboxylic acids with unbranched hydrocarbon chains of 4-24 carbon atoms. They are present in all organisms as components of fats and membrane lipids, in these compounds, they are esterified with alcohols (glycerol, sphingosine, or cholesterol). However, fatty acids are also found in small amounts in unesterified form. In this case, they are known as free fatty adds (FFAs). As free fatty acids have strongly amphipathic properties (see p. 28), they are usually present in protein-bound forms. 

While the above reactions are responsible for meaty flavors, animal fat plays an important role in the formation of the characteristic spedes flavor of cooked meat (14). More than 100 compounds have been identified in heated beef fat, including aldehydes, n-alkanes,n-alkenes, fatty adds, ketones, lactones and heterocyclics (15-18). Of these compounds, the lactones, metltyl ketones and free fatty adds appear to be the most important for desirable meat flavor. 

Electroconvulsive shock (ECS), as well as ischemia, induces increases in free fatty add (FFA) and diacylglycerol (DAG) in the rat brain, probably due to the breakdown of membrane phospholipids through the activation of phospholipases (PLC, PLAj/A,). EGb treatment (100 mg/kg/day, p.o. for 14 days) selectively decreases endogenous FFA levels and increases endogenous DAG levels in the hippocampus. Therefore, ECS-induced accumulation of FFAis prevented in the hippocampus of EGb-treated rats during clonic seizures (30 sec to 2 min after... 

ACID NUMBER. A term used in the analysis of fats or waxes to designate the number of milligrams of potassium hydroxide (KOH) required to neutralize the free fatty adds in 1 gram of substance. The determination is performed by titrating an alcoholic solution of the wax or fat with tenth or half-normal alkali, using phcnolphthalcin as indicator. 

Bynum, D. G., Senyk, G. F., and Barbano, D. M. (1984). Determination of free fatty add content of Cheddar cheese by a copper soap method. J. Dairy Sci. 67,1521-1524. 

Clausen, P.A., Wilkins, C.K. and Wolkoff, P. (1998) Gas chromatographic analysis of free fatty adds and fatty add salts extracted with neutral and addified dichloromethane from office floor dust. Journal of Chromatography A, 814, 161-70. 

Roseth S, Fykse EM, Fonnum F (1998) The effect of arachidonic acid and free fatty adds on vesicular uptake of glutamate and gamma-aminobutyric acid. Eur J Pharmacol 341 281-288. 

AQUEOUS LAYER salts, peptides, sugars, free fatty adds, vitamins cofactors------------... 

R. Brandes, R, K. Ocltner, R. A, Wfcifiagei and N. Lysenbo. Specific and saturable binding of albumin to rat adipocytes Modulation by epinephrine and possible role in free fatty add transfer. Biochenu Biopkys. Res. Cotnmuit. 705 821-827 (1982),... 

Hyperalbuminemia is a relatively rare condition, but hypoalbumin-emia occurs frequently in severe hepatic and renal disorders. In disorders such as these, there may also be relatively elevated serum concentrations of free fatty adds, which may compete with drugs for binding sites on HSA. The S-enantiomer of the glucuronide conjugate of the 1,4-benzodiazepin-2-one drug oxazepam binds to site II on HSA, whereas its antipode binds in an apparently nonspecific manner. The elevated levels of fatty adds found in renally impaired patients can therefore cause a displacement of oxazepam glucuronide (52), which may be enantioselective. 

B. SebiUe, N. Thuaud, J. F TiUement, and J. Brienne, Effect of long chain free fatty adds on the conformation of the human serum albumin warfarin binding site as studied by circular dichroism, Inl. ]. Bid. Macromd., 6 175 (1984). 

Schwenk, W, F, Hale, D, E., and Hay mond, M, W. (1986). Decreased fasting free fatty adds with [.-carnitine in chiidien with carnitine deficiency Pediatr. Res. 23,491-494. 

PC can come from the diet or be synthesized in the body. Dietary PC is cleaved by a pancreatic enzyme, phospholipase B, that catalyzes hydrolysis of the fatty add from carbon-2 (C-2) of the glycerol backbone. This hydrolysis produces a free fatty add and l-acyh3-phosphocholine glycerol. The latter compound is called lysolecithin, because its parent compound PC is known as lecithin. Lysoledthin and the free fatty acid are absorbed by the enterocyte, converted back to PC, and then packaged into chylomiorons that are released into the lymphatic system. A small fraction of the choline derived from dietary PC enters the bloodstream as free choline. 

Fatty acids occurring as TGs in the VLDLs are derived from three sources (1) free fatty adds taken up by the liver from the bloodstream (2) TGs derived from chylomicron remnants, intermediate-density lipoproteins (IDLs), LDLs, and HDLs taken up by the liver via the process of endocytosis and f3) fatty acids synthesized de novo in the liver from carbohydrates. Note that the free fatty acids in plasma are tightly, although not covalently, associated with plasrna albumin. 

E) Preparation of Free Fatty Adds. Place 5 g of the crude soap in a 50-ml beaker, add 30 ml of water, and heat nearly to boiling until it dissolves. Add 7-8 ml of 6 iV sulfuric acid, and stir until the oily layer of fatty acids separates as a distinct layer on the top. Cool the mixture in an ice-salt mixture for about 15-20 minutes. Lift the solidified cake of fatty acids, press between filter paper, and place in a small evaporating dish. 

Figure 1. Mass and heat flows in the free fatty adds-palm oil-ethane-acetone tem.

Adipose triacylglycerols are released as free fatty adds and glycerol. The fatty adds are oxidized to C02 and H20 by various tissues. In the liver, the fatty adds are converted to ketone bodies, and the glycerol serves as a source erf carbon for gluconeogenesis. 

Amphetamines increase the concentration of free fatty adds. Morphine increases the activity of amylase and lipase, alanine and aspartate aminotransferases, ALP and the serum bilirubin concentration. The concentrations of gastrin, TSH, and prolactin are also increased. In contrast the concentrations of insulin, norepinephrine, pancreatic polypeptide, and neurotensin are decreased. Heroin increases the plasma concentrations of cholesterol, thyroxine, and potassium. PCO2 is increased but PO2 is decreased. The plasma albumin concentration is also decreased. Cannabis increases the plasma concentrations of sodium, potassium, urea, chloride, and insulin but decreases those of creatinine, glucose, and urate. 

In these cases it Is much more convenient to prepare an ester from the alcohol by the action of the chloride of a higher fatty add, and subjecting this to distillation by which it is decomposed into an hydrocarbon of the ethylene series and the free fatty add, e.g. r... 

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