Sucrose transesterification

Olestra is prepared by a solvenfless transesterification process in which sucrose is treated with methyl ester of fatty acids in the presence of sodium methoxide between 100—180°C for 14 hours (68). The manufacturing process involves removal of the unreacted fatty acid esters by enzymic hydrolysis... 

The transesterification of sucrose has been performed with a fatty acid ester of a volatile alcohol in the presence of an alkaline catalyst in a dipolar, aprotic solvent.142 The reaction of sucrose (293 mmoles) with methyl dodecanoate (293 mmoles) in A/,N-dimethylformamide in the presence of sodium methoxide in a pressure bomb for 8 h at 130° gave, after solvent extraction and crystallization, sucrose mono(dodecanoate) (m.p. 72-80° [a]D+52°) in 50% yield.142 Commercialization of these sucrose esters has so far been limited, in part because of the use of expensive solvents, and, in part, because solvent remaining in the product makes it unsuitable for use as a food emulsifier. In view of this situation, methods have been developed in which the use of toxic and expensive solvents has been avoided. 

Parrish (1977) reviewed the research and development of lactose ester-type surfactants carried out by Scholnick and his colleagues (Scholnick et al. 1974, 1975 Scholnick and Linfield 1977). Their initial attempts to form lactose esters followed the same transesterification procedures that had been used with sucrose (a fatty acid methyl ester in N,N-dimethylformamide with potassium carbonate as the catalyst). Their successful approach was the reaction of lactose in N-methyl-2-pyrrolidone as the solvent with fatty acid chlorides, resulting in yields of 88 to 95% for esters of lauric, myristic, palmitic, stearic, oleic, and tallow fatty acids. The principal product was the monoester, which is important for detergent use, since diesters and higher esters of lactose are not water soluble. 

V. Molinier, K. Wiesniewski, A. Bouchu, J. Fitremann, and Y. Queneau, Transesterification of sucrose in organic medium Study of acyl group migrations, J. Carbohydr. Chem., 22 (2003) 657-669. 

N. R. Pedersen, P. J. Hailing, L. H. Pedersen, R. Wimmer, R. Matthiesen, and O. R. Veltman, Efficient transesterification of sucrose catalysed by the metalloprotease thermolysin in dime-thylsulfoxide, FEBS Lett., 519 (2002) 181-184. 

P. Potier, A. Bouchu, G. Descotes, and Y. Queneau, Proteinase N-catalysed transesterifications in DMSO-water and DMF-water Preparation of sucrose methacrylate, Tetrahedron Lett., 41 (2000) 3597-3600. 

The best known application of N V-dimethylformamide in sucro-chemistry is as a solvent for a transesterification reaction leading to sucrose mono- and poly-esters of fatty acids. This reaction has been extensively studied and reviewed,73,259-269 and will not be further... 

Figure 5.1 Transesterification activity of (a) 0.025 or (b) 0.3 mg of lipase BC co-lyophilized with different amounts of sucrose ( ), trehalose (x) and mannitol ( ). Activity was tested in toluene by measuring the rate of 1-...

Chromatographic batch reactors are employed to prepare instable reagents on the laboratory scale (Coca et al., 1993) and for the production of fine chemicals. These applications include the racemic resolution of amino acid esters (Kalbe et al., 1989), acid-catalyzed sucrose inversion (Lauer, 1980), production of dextran (Zafar and Barker, 1988) and saccharification of starch to maltose (Sarmidi and Barker, 1993a). Sardin et al. (1993) employed batch chromatographic reactors for different esterification reactions such as the esterification of acetic acid with ethanol and the transesterification of methylacetate. Falk and Seidel-Morgenstern (2002) have investigated the hydrolysis of methyl formate. 

Many carbohydrate-based fat substitutes are mixtures of sucrose esters formed by chemical transesterification or interesterification of sucrose with one to eight FAs. The class with six to eight FAs are called sucrose FA polyesters. These molecules are too large to be broken down by intestinal lipase enzymes and, for that reason, do not show any caloric value (Voragen, 1998). 

A copolymer of this monomer with N,N melhylenebis (acrylamide) imbibed 100 times its weight of water. This swelling was not affected by sodium chloride in the water. Most super-slurpers swell less in the presence of dissolved salts. Thus, the new copolymer may be of use in collecting urine in diapers. Another polymeric hydrogel was made by polymerization of sucrose-l -acrylate using sucrose-6,1 -diacrylate (prepared by enzymatic transesterification of sucrose and vinyl acrylate) as the cross-linking agent.155... 

The polyols that can be used for transesterification with castor oil are glycerol, trimethylolpropane, pentaerythritol, sorbitol, and sucrose. The catalysts of the reaction between castor oil and various polyols are alkali alcoholates, such as sodium methoxide or potassium methoxide. Thus, by the reaction of one mol of castor oil with two mols of glycerol, a mixture of mono, di and triglycerides of ricinoleic acid, having a much higher hydroxyl number than the initial castor oil, of around 420-430 mg KOH/g (reaction 17.5) is obtained. 

Sucrose esters are manufactured by transesterification of sucrose with fatty acid methyl esters in a suitable solvent system where both components are soluble, such as dimethylformamide or dimethyl-sulphoxide (Benson, 1967). The sucrose esters are purified by distillation and crystallization from e.g. ethyl acetate in order to remove the solvent completely. For food use the content of dimethylformamide must be less that 1 mg/kg. An alternative... 

The original preparation of sucrose esters of fatty acids involves the transesterification of a triglyceride molecule with sucrose in the presence of a basic catalyst at 90°C in Af,Af-dimethylformamide (DMF) as solvent (Fig. 7.3) [4]. 

Fatty acid methyl esters are currently used in transesterification reactions with sucrose. The formation of methanol, which can be distilled off, drives the estalfication process in favour of the sucrose ester and improves yields. A solvent-less process using a slurry of sucrose and potassium carbonate in fatty acid methyl este or triglycaide oil at 130°C has been developed more recently [5]. 

Thus, 6-0-lauroyl(pamitoyl)sucroses were obtained in 70-80 per cent yields by performing the transesterification in a mixture of tert-amyl alcohol and DMSO in the presence of lipase from Humicola lanuginose [ 13]. 

Sugar-based fatty acid ester diols have also been prepared by transesterification of epoxidised oleates with methyl a-D-glucopyranoside and sucrose, followed by hydrolysis of the oxirane ring [57]. These fully bio-based monomers were polymerised with an aliphatic diisocyanate to produce PU whose structure could be oriented toward a linear architecture (when the sugar OH groups were not involved) or a network (if at least some of them participated in the polycondensation) by changing the solvent medium. 

Other food emulsifiers are made by transesterification of fatty acid methyl esters with poly glycerols, sorbitan, sucrose and stearoyl lactate (Figure 10.2). Sugar, sorbitan fatty esters and polyoxyethylene sorbitan esters are used to stabilize oil-in-water food emulsions. Optimum emulsification is achieved with combinations of emulsifiers. Margarines are made with a combination of monoglycerides and lecithin, and cake mixes with a mixture of monoglycerides and propylene glycol monoesters. 

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