Enzymatic hydrolysis of triglyceride

Fig. 13.11 Schematic representation of the hollow fiber membrane biorector for the enzymatic hydrolysis of triglycerides. A hydrophilic membrane has been used, coated with lipase on the lipid side [85].

In addition to de novo synthesis from acetyl CoA, fatty acids can be derived from the enzymatic hydrolysis of triglycerides. The primary form in which fatty acids are stored and transported between cells, triglycerides consist of three fatty acyl chains esterified to glycerol hence they are also called triacylglycerols (see Figure 18-2). Complete hydrolysis of a triglyceride molecule yields three unesterified fatty acid molecules, or free fatty acids (FFAs), and a glycerol molecule. 

Figure 5 Enzymatic hydrolysis of triglycerides. Some lipases exhibit specificity on the type of fatty acid (chain length, saturation) or on the position 1 or 2 of glycerol.

Since then, this approach has been vigorously studied by a number of laboratories (29-32). Most recently, the application of lipases to the enzymatic hydrolysis of triglycerides led to the construction of a semicommercial plant for the manufacture of ultrapure unsaturated fatty acids (33). 

Enzymatic Processes. The enzyme hydrolysis of triglycerides is catalyzed by lipases ... 

Marquez-Ruiz, G., Guevel, G., and Doharganes, M.C. (1998) Applications of Chromatographic Techniques to Evaluate Enzymatic Hydrolysis of Oxidized and Polymeric Triglycerides hy Pancreatic Lipase In Vitro, J. Am. Oil Chem. Soc. 75, 119-126. 

The choice of surfactant is of importance for the rate of many enzymatic reactions in microemulsions. For instance, it has been found that whereas lipase-catalyzed hydrolysis of triglycerides is rapid in microemulsions based on AOT, it is extremely sluggish when... 

Figure 12 Enzymatic hydrolysis of a triglyceride in combination with migration of the acyl group from the 2- to the 1-position.

Various membrane reactors have been proposed to allow recovery of products from microemulsions and permit to reuse the biocatalyst in various enzymatic processes such as hydrolysis of triglycerides [124,182], synthesis of esters [183,184], and peptide synthesis [65,185,186]. These reactors take advantage of the potential of synthetic semipermeable membranes, that usually are ultrafiltration membranes, to retain enzymes on the membrane and to recover products on the permeate side. The productivities as well as the enzyme stability in such reactors are usually high. 

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%. 

Triacylglycerol. Triglyceride a compound consisting of three molecules of fatty acids esterified to glycerol. It is a neutral fat synthesized from carbohydrates for storage in animal adipose cells. On enzymatic hydrolysis, it releases free fatty acids in the blood. Tuberculosis. Any of the infectious diseases of man and animals caused by species Mycobacterium and characterized by the formation of tubercles and caseous necrosis in the tissues. 

The biochemical stability of food colloids is now attracting considerable research interest because of its obvious relevance to the delivery and bioavailability of nutrients and nutraceuticals in vivo. In particular, the processes of enzymatic hydrolysis occurring at the triglyceride-water interface appear important because most dietary lipids are present in the human stomach at some stage in the form of emulsified droplets (size 20-40 pm) (Armand et al., 1994 McClements et al., 2008 Dickinson, 2008 Singh et cil, 2009 McClements and Decker, 2009). 

Enzymatic hydrolysis is a nondestructive alternative to saponification for removing triglycerides in vitamin K determinations. For the simultaneous determination of vitamins A, D, E, and K in milk- and soy-based infant formulas and dairy products fortified with these vitamins (81), an amount of sample containing approximately 3.5-4.0 g of fat was digested for 1 h with lipase at 37°C and at pH 7.7. This treatment effectively hydrolyzed the glycerides, but only partially converted retinyl palmitate and a-tocopheryl acetate to their alcohol forms vitamin D and phyllo-quinone were unaffected. The hydrolysate was made alkaline in order to precipitate the fatty acids as soaps and then diluted with ethanol and extracted with pentane. A final water wash yielded an organic phase containing primarily the fat-soluble vitamins and cholesterol. 

SCFs offer a nonaqueous environment which can be desirable for enzymatic catalysis of lipophilic substrates. The lipophilic substance cholesterol is 2 to 3 orders of magnitude more soluble in CX>2-cosolvent blends than in waterQ). In CO2 based blends, it may be oxidized to cholest-4en-3one, a precursor for pharmaceutical production using an immobilized enzyim(22). The enzyme polyphenol oxidase has been found to be catalytically active in supercritical CO2 and fluoroform (22). The purpose of using a SCF is that it is miscible with one of the reactants-oxygen. Lipase may be used to catalyze the hydrolysis and interesterification of triglycerides in supercritical OO2 without severe loss of activity(24). These reactions could be integrated with SCF separations for product recovery. 

The separation,purification and concentration of a thermosensitive bioactive compound from a lysate has been carried out combining UF, ion exchange and RO with significant cost reduction and productivity increase. Enzyme membrane reactors have been used for triglyceride enzymatic hydrolysis and product separation. Thermophi1ic,thermostable enzyme ultrafiltration membrane have been prepared, and used in high temperature lactose hydrolysis. 

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