Esters, sucrose products

Finally, an elegant example of a product derived from renewable raw materials is the bioemulsifier, marketed by Mitsubishi, which consists of a mixture of sucrose fatty acid esters. The product is prepared from two renewable raw materials - sucrose and a fatty acid - and is biodegradable. In the current process the reaction is catalysed by a mineral acid, which leads to a rather complex mixture of mono- and di-esters. Hence, a more selective enzymatic esterification (Fig. 1.43) would have obvious benefits. Lipase-catalysed acylation is possible [126] but reaction rates are very low. This is mainly owing to the fact that the reaction, for thermodynamic reasons, cannot be performed in water. On the other hand, sucrose is sparingly soluble in most organic solvents, thus necessitating a slurry process. 

The major problem associated with the enzymatic acylation of sucrose is the incompatibility of the two reactants sucrose and a fatty acid ester. Sucrose is hydrophilic and readily soluble in water or polar aprotic solvents such as pyridine and dimethylformamide. The former is not a feasible solvent for (trans)esterifi-cations, for obvious thermodynamic reasons, and the latter are not suitable for the manufacture of food-grade products. The selective acylation of sucrose, as a suspension in refluxing tert-butanol, catalyzed by C. antarctica lipase B, afforded a 1 1 mixture of the 6 and 6 sucrose monoesters (Fig. 8.39) [208]. Unfortunately, the rate was too low (35% conversion in 7 days) to be commercially useful. 

These procedures are commonly used to produce sucrose esters such as stearates, taUowates, oleates, pahni-tates, myristates and laurates that are actually complex product mixtures containing 70 pw cent of monoestCT and 30 per cent of di-, tri- and poly-esters. Global production of sucroesters is estimated at 5 0001 pw year. 

Methyl fatty acid esters, by-products of the production of glycerol from fats, are readily available. Transesterification with sucrose, under conditions in which methanol is removed continuously, results in the equilibrium shifting towards complete reaction (13). 

Sucrose Esters. These newer emulsifiers, approved for direct addition in the United States in 1983 (35), ate formed when sucrose is combined with various fatty acids and the resulting emulsion is dehydrated. These additives are odorless and tasteless, and can withstand the retort process. They are used in products when standards of identity do not preclude their use, such as baked goods, baking mixes, dairy product analogues, fto2en dairy desserts and mixes, and whipped milk products (39). High price has limited use in the United States, but these compounds ate used extensively in Japan as emulsifiers in baked goods (40). 

Acidic Cation-Exchange Resins. Brmnsted acid catalytic activity is responsible for the successful use of acidic cation-exchange resins, which are also soHd acids. Cation-exchange catalysts are used in esterification, acetal synthesis, ester alcoholysis, acetal alcoholysis, alcohol dehydration, ester hydrolysis, and sucrose inversion. The soHd acid type permits simplified procedures when high boiling and viscous compounds are involved because the catalyst can be separated from the products by simple filtration. Unsaturated acids and alcohols that can polymerise in the presence of proton acids can thus be esterified directiy and without polymerisation. 

Sucrose reacts with fatty acids to produce esters with degrees of esterification (DE) from 1 to 8 and hydrophi1 ic /Iipophi1 ic balances that provide them with numerous appHcations. Primary producers are Japan and the Netherlands, with total production at 6000 t/yr. Sucrose esters are nontoxic and biodegradable, and are approved for use in the EC, Japan, and the United States. 

Phosphate Esters. The phosphorylation of sucrose using sodium metaphosphate has been reported (78). Lyoptulization of a sodium metaphosphate solution of sucrose at pH 5 for 20 hours followed by storage at 80°C for five days produced a mixture of sucrose monophosphates. These products were isolated by preparative hplc, with a calculated yield of 27% based on all organic phosphate as sucrose monoesters. Small proportions of glucose and fmctose were also formed. 

Besides these normal technical products, many other different types of a-sulfo fatty acid esters have been described in the literature. For example, Weil et al. prepared a-sulfopalmitates and stearates with higher alcohols [19] and also monoesters of polyhydric alcohol [39] and of hexitols and sucrose [40] for their special properties. In addition to the sodium salt, Stirton et al. used other cations, such as Li, NH4, K, Mg, and Ca, to study the relationship between the structure and the surfactant properties [30]. 

The practical effect of this very wide HLB range is that sucrose esters can be used in a very wide range of confectionery products. Notably, it is not necessarily the same sucrose ester (Table 6). Sucrose esters are stable up to 180°C. 

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. 

Engineering and Pilot Plant Data for the Commercial Production of Sucrose Esters for the Ink, Paint, and Protective Coatings Industry, Sugar Research Foundation, Inc., New York, 1963. 

No-calories fat substitutes, such as sucrose polyesters (Olestra), which are synthesized from sucrose and fatty acid methyl esters, have been widely studied and several snacks fried in this medium are available in the market place. This product has no calories since digestive enzymes are not able to break it down due to structural impairment. A major disadvantage that prevents a wide acceptance of this product is related to the gastrointestinal discomfort that may be caused to some individuals (Dobraszczyk et ah, 2006, p. 104). 

Sucrose octapropionate and octabutyrate have also been prepared but have not been examined so extensively as the acetate. Hurd and Gordon obtained the octapropionate in crystalline form, whereas the octabutyrate was obtained by Cox and coworkers and more recently by Wolff as a liquid. Both of these products, in view of their very high boiling points, may be useful as plasticizing agents. The ester with methacrylic acid would be of interest but so far attempts made in these laboratories to obtain a monomeric substance have failed and only an insoluble polymer is obtained. 

While "natural" is the current catch-phrase of today s consumer, research must still be performed for the development of synthetic compounds that can lower the cost of production of food that can be utilized to develop other less costly food items. Amino acids or proteins with O-aminoacyl sugars as part of their residue have been examined for their taste impact Chapter 12). Several of these components have been shown to be potential replacements for salt (NaCl) this would have a significant impact for individuals with high blood pressure or with a propensity to other coronary or renal problems. Some glycosides, represented by some sucrose esters, are approved by the United States Food and Drug Administration for food use. These glycosides have potential use in the preparation of food materials and can lead to more cost effective means of production Chapter 18). 

Low-molecular-weight surfactants ( emulsifiers ) are important ingredients in food products. The types of surfactants most commonly studied in food colloids research are phospholipids (lecithin), mono/diglycerides (particularly glycerol monostearate), polysorbates (Tweens), sorbitan monostearate or monooleate (Spans), and sucrose esters. These small lipid-based amphiphiles can typically lower the interfacial tension to a greater extent than the macromolecular amphiphiles such as proteins and certain gums (Bos and van Vliet, 2001). 

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. 

Two groups of sucrose derivatives of herbicidal acids have been reported. The herbicidal properties of the sucrose esters of (2,4-dichlorophenoxy)-acetic acid and other analogs differed somewhat from the salts of the free herbicide acids. This could be accounted for as being due to differences in solubility and penetration, since it is unlikely, by analogy to the fatty acid esters, that the sucrose esters would remain intact in the plant. 0 The second set of sucrose esters were water-soluble sirups, having surfactant properties, prepared from reaction products of hydroxyethyl ethers of sucrose or diglycidyl ethers of poly(oxyetbylene glycol) with (2,4,5-tri-chlorophenoxy) acetic acid or other herbicidal acids. 1... 

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