Triglycerides, hydrolysis

The quaHty, ie, level of impurities, of the fats and oils used in the manufacture of soap is important in the production of commercial products. Fats and oils are isolated from various animal and vegetable sources and contain different intrinsic impurities. These impurities may include hydrolysis products of the triglyceride, eg, fatty acid and mono/diglycerides proteinaceous materials and particulate dirt, eg, bone meal and various vitamins, pigments, phosphatides, and sterols, ie, cholesterol and tocopherol as weU as less descript odor and color bodies. These impurities affect the physical properties such as odor and color of the fats and oils and can cause additional degradation of the fats and oils upon storage. For commercial soaps, it is desirable to keep these impurities at the absolute minimum for both storage stabiHty and finished product quaHty considerations. 

Sulfated Natural Oils and Fats. Sulfated natural triglycerides were the first nonsoap commercial surfactants introduced in the middle of the nineteenth century. Since then sulfates of many vegetable, animal, and fish oils have been investigated (see also Fats AND FATTY oils). With its hydroxyl group and a double bond, ricinoleic acid (12-hydroxy-9,10-octadecenoic acid) is an oil constituent particularly suited for sulfation. Its sulfate is known as turkey-red oil. Oleic acid is also suited for sulfation. Esters of these acids can be sulfated with a minimum of hydrolysis of the glyceride group. Polyunsaturated acids, with several double bonds, lead to dark-colored sulfation products. The reaction with sulfuric acid proceeds through either the hydroxyl or the double bond. The sulfuric acid half ester thus formed is neutralized with caustic soda ... 

Oils are mixtures of mixed esters with different fatty acids distributed among the ester molecules. Generally, identification of specific esters is not attempted instead the oils are characterized by analysis of the fatty acid composition (8,9). The principal methods have been gas—Hquid and high performance Hquid chromatographic separation of the methyl esters of the fatty acids obtained by transesterification of the oils. Mass spectrometry and nmr are used to identify the individual esters. It has been reported that the free fatty acids obtained by hydrolysis can be separated with equal accuracy by high performance Hquid chromatography (10). A review of the identification and deterrnination of the various mixed triglycerides is available (11). 

Endothelial-anchored enzyme in liver primarily responsible for hydrolysis of triglycerides and phospholipids in Intermediate Density Lipoproteins (IDL) and High Density Lipoproteins (HDL). 

Lipoprotein formed by hydrolysis of triglycerides in VLDL elevated in type III hyperlipoproteinemia. 

Endothelial anchored enzyme in muscle and adipose tissue primarily responsible for hydrolysis of chylomicron and VLDL triglycerides. 

Fatty acids, respectively the alkali salts of fatty acids, have long been produced by saponification of fats or fatty oils by alkali lye. At present the free acids are produced either by hydrolysis of the triglycerides with water in an uncatalyzed reaction at 210-260°C under a pressure of 20-60 bar or in a cata-... 

A continuous stirred tank reactor has been reported for the hydrolysis of the triglycerides existing in vegetable oil in the presence of the aqueous phase and for synthesis reactions (Table 5). A microfilter can be used to prevent the immobilized enzyme from leaving the reactor. Kawano et al. [115] investigated the hydrolysis of olive oil in octane with Candida cylindracea lipase in aqueous solution in a Vibro Mixer reactor containing vibration plates connected to the crankshaft of a motor and oscillated with fixed rates. 

Figure 13.16.5 The hydrolysis or saponification of a triglyceride to yield the constituent acids and glycerol.

The hypotriglyceridemic action of fibrates involves combined effects on LPL and apolipoproteinCIII (apoCIII). LPL is up-regulated [11], whereas apoCIII, an inhibitor of LPL, is down-regulated [12], leading to enhanced hydrolysis of triglyceride-... 

The concept of zeolite action was tested in a particular reaction where the enzyme is exposed from the beginning to an acidic environment the esterification of geraniol with acetic acid catalyzed by Candida antarctica lipase B immobilized on zeolite NaA [219]. Lipases have been used for the hydrolysis of triglycerides and due to their ambivalent hydrophobic/hydrophilic properties they are effective biocatalysts for the hydrolysis of hydrophobic substrates [220]. When water-soluble lipases are used in organic media they have to be immobilized on solid supports in order to exhibit significant catalytic activity. 

Generally, alkaline saponification in hydroalcoholic KOH is the most widespread approach [11 13]. This allows us to cleave ester bonds and, if necessary, to separate the saponifiable fraction (acids) and unsaponificable fraction (alcohols, sterols, and hydrocarbons). Generally, 3 h of saponification in 10% KOH in water/methanol (3 1) at 60 °C achieves a quantitative yield for triglycerides. Wax esters are less prone to hydrolysis and generally need stronger conditions. Quantitative hydrolysis of beeswax long chain esters has been obtained using 10% KOH in ethanol assisted by microwaves, for 60 min at 80 °C and at 200 W [21],... 

In the case of paint samples where lipids are often admixed with proteinaceous binders, in some cases acidic hydrolysis is proposed to simultaneously hydrolyse proteins and triglycerides in the same step [35,36], although in acidic conditions the hydrolysis of triglycerides is not quantitative. 

All the approaches based on a chemolysis step and GC analysis give detailed information on the FA and alcohol profiles, but do not reveal anything about the extent of the hydrolysis of any triglycerides and wax esters in the sample. 

Determining the degree of hydrolysis of lipids is particularly interesting when degradation is being studied, since the hydrolysis of the ester bond is one of the main decay paths for triglycerides and wax esters. 

Adipose Adipose tissue is the primary storage facility for fat. Fat is stored in these tissues as an intracellular droplet of insoluble triglyceride. A hormone-sensitive lipase mobilizes triglyceride stores by hydrolysis to free fatty acids. 

Monoglyceride (MG) is one of the most important emulsifiers in food and pharmaceutical industries [280], MG is industrially produced by trans-esterification of fats and oils at high temperature with alkaline catalyst. The synthesis of MG by hydrolysis or glycerolysis of triglyceride (TG) with immobilized lipase attracted attention recently, because it has mild reaction conditions and avoids formation of side products. Silica and celite are often used as immobilization carriers [281], But the immobilized lipase particles are difficult to reuse due to adsorption of glycerol on this carriers [282], PVA/chitosan composite membrane reactor can be used for enzymatic processing of fats and oils. The immobilized activity of lipase was 2.64 IU/cm2 with a recovery of 24%. The membrane reactor was used in a two-phase system reaction to synthesize monoglyceride (MG) by hydrolysis of palm oil, which was reused for at least nine batches with yield of 32-50%. 

Starch and fatty acids are the main food constituents of biomass. Sugar is derived from starch by hydrolysis or directly by extraction from sugar cane or beet. Fermentation converts sugars into alcohol that can be directly used as fuel, or in principle can be used as the raw material of a bioreftnery plant for further upgrading. Triglycerides, derived from oil seeds, are used to be converted into biodiesel through transesterification processes (Fig. 1.14). 

In adipose tissue, insulin stimulation suppresses triglyceride hydrolysis (to free fatty acids and glycerol) by activating cAMP phosphodiesterase (cAMP PDE). Cyclic AMP, (3, 5 cAMP), is required to stimulate hormone sensitive lipase (HSL), the enzyme which hydrolyses triglyceride within adipocytes PDE converts active 3, 5 cAMP to inactive 5 AMP thus preventing the stimulation of HSL. The net effect of insulin on lipid metabolism is to promote storage. 

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