Sucrose-sorbitol polyols

Alditols are sweet. Xyhtol has essentially the same sweetness as sucrose sorbitol is about half as sweet as sucrose. In chewing gum, polyols provide texture, sweetness, and mouthfeel and reduce the iacidence of dental caries. 

The mixtures of sucrose - triethanolamine, usually of 1-1.5/1 (sucrose/triethanolamine) [9] are very stirrable mixtures, at the propoxylation temperature, and are frequently used in practice. Triethanolamine can be replaced by diethanolamine, monoethanolamine and even by ammonia [59]. The triol is formed in situ by the reaction of ammonia or primary or secondary ethanolamines with PO. The polyols based on sucrose - triethanolamine (Table 13.6) are frequently used to make rigid PU foams for thermoinsulation of freezers. The mixtures of sucrose - sorbitol lead easily to high functionality polyols, sorbitol having an excellent solvating capability for solid sucrose. 

Sorbitol is the most important higher polyol used in direct esterification of fatty acids. Esters of sorbitans and sorbitans modified with ethylene oxide are extensively used as surface-active agents. Interesteritication of fatty acid methyl esters with sucrose yields biodegradable detergents, and with starch yields thermoplastic polymers (36). 

Surface-Active Agents. Polyol (eg, glycerol, sorbitol, sucrose, and propylene glycol) or poly(ethylene oxide) esters of long-chain fatty acids are nonionic surfactants (qv) used in foods, pharmaceuticals, cosmetics, textiles, cleaning compounds, and many other appHcations (103,104). Those that are most widely used are included in Table 3. 

Yeast Fermenting in Dough. When yeast is in a bread dough the traces of sugars present can be fermented directly. As yeast contains the enzyme invertase, any sucrose present can be inverted into dextrose and fructose which can then be fermented. If any dextrose from a high DE glucose syrup is present then it can be directly fermented. If there is any lactose present it can not be fermented at all. Similarly, any polyols such as sorbitol can not be fermented. 

Other sugars and polyols also complex with iron. Fructose is the most effective, but sorbitol, glucose, galactose, lactose, sucrose, pentoses and tetroses can also keep hydrolyzed ferric salts in solution. An excess of sugar must always be present in order to prevent ferric hydroxide precipitate. There appears to be a competition between the OH- and sugar hydroxyls for the Fe3+. 

Polyols are frequently used sugar substitutes and are particularly suited to situations where their different sensory and functional properties are attractive. In addition to sweetness, some of the polyols have other useful properties. For example, although it contains the same number of calories/gram as other sweeteners, sorbitol is absorbed more slowly from the digestive tract than is sucrose. It is, therefore, useful in making foods intended for special diets. When consumed in large quantities (1-2 oz 25,059 g)/dav, sorbitol can have a laxative effect, apparently because of its comparatively slow intestinal absorption. 

Sweeteners can be divided into two groups, nonnutritive and nutritive sweeteners. The nonnutritive sweeteners include saccharin, cyclamate, aspartame, acesulfame K, and sucralose. There are also others, mainly plant extracts, which are of limited importance. The nutritive sweeteners are sucrose glucose fructose invert sugar and a variety of polyols including sorbitol, mannitol, malt-itol, lactitol, xylitol, and hydrogenated glucose syrups. 

Many excipients used by the pharmaceutical industry in the last 15 years in sugar-free medical preparations probably come under the category of essentially new excipients. Pressure for their introduction has been encouraged by the definite relationship between the dietary consumption of sucrose and the incidence of dental caries. " "" These materials include intense sweeteners such as saccharin and cyclamate plus bulk sweeteners such as the polyols sorbitol, xylitol, and lactitol. These materials are all either approved for food use or have pharmacopoeia monographs in existence or in draft. Fiterature reviews show number of... 

In the preparation of TDI-based semi-prepolymer, TDI-80/20 and a polyol, preferably sucrose- or sorbitol-based polyol, are reacted to obtain about 30% free NCO-containing semi-prepolymers. 

FIGURE 1 Molecular formulas of some sweet molecules, representative of the major natural classes carbohydrates (sucrose), polyols (glycerol, sorbitol), amino acids (glycine, tryptophan), peptides (aspartame, monatin). 

The most important low molecular weight polyols used as starters for polyether polyols destined for rigid PU foams synthesis are glycerol, trimethylolpropane (TMP), triethanolamine, pentaerythritol, dipentaerythritol, a-methyl glucoside, xylitol, sorbitol and sucrose [1-27]. The main properties of these starter polyols, which are of interest for polyurethane chemistry, are presented in Table 13.1. 

Unfortunately, it is a difference between a starter, such as nonylphenol, or a fatty alcohol, which have only one type of hydroxyl group and polyols. Some polyols used as starters for rigid polyether polyols have in the same molecule various types of hydroxyl groups (for example, primary hydroxyls and secondary hydroxyls) which do not have equivalent reactivities in the alkoxylation reactions. For example, sorbitol has two primary hydroxyls and four secondary hydroxyls, sucrose has three primary hydroxyls and five secondary hydroxyls. In both polyols, the secondary hydroxyls have different substituents and they are not totally equivalent. TMP, pentaeriythritol and dipentaerythritol have only one type of equivalent primary hydroxyl group. Thus, the initiation reaction (reaction of PO with hydroxyl groups of starter) is in fact the sum of the reactions of PO with each type of hydroxyl group of the starter ... 

The representative examples are the synthesis of sucrose-based polyether polyols with a low melting point. Sucrose is well solvated by low molecular weight polyols such as glycerol, diethylene glycol, dipropylene glycol, triethanolamine and sorbitol. At the... 

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. 

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