Glucose fructose production

Because alkali degradation of sucrose does not result in inversion products, in slightly alkaline solution (pH < 8.5), the loss of sucrose to invert sugar (glucose + fructose) is a consequence of the acid hydrolysis mechanism, which provides D-glucose and D-fructose for further alkaline degradation. 

Fourteen DFAs and some oligomers were identified in caramel obtained by thermal treatment of inufin. - Monosaccharides (glucose, fructose), dehydration products (1,6-anhydro-p-D-glucopyranose, 1,6-anhydro-p-D-glucofuranose), disaccharides (gentiobiose and isomaltose), and oligosaccharides were also found in glucose and sucrose caramel. ... 

Glucose isomerase catalyzes the conversion of D-glucose to D-fructose and has also been used extensively on an industrial scale.1184 Some, but not all, enzymes of this family require Co specifically, while others can function with other divalent ions. Environmental and health issues limit the concentrations of Co in culture media during D-fructose production and other metal ions are being sought as substitutes. Although the active site structure remains unknown, EXAFS, optical and EPR spectroscopy has suggest a low-spin divalent Co ion, bound by N and O-donors only (no S-donors). 

The distinctive aroma of ammonia is often apparent in bakeries but not in the final product. Bakers yeast performs its leavening function by fermenting such sugars as glucose, fructose, maltose, and sucrose. The principal products of the fermentation process are carbon dioxide gas and ethanol, an important component of the aroma of freshly baked bread. The fermentation of the sugar, glucose—an example of a decomposition reaction — is given by the equation in Fig. 5.19.1. 

In comparison with sucrose (the annual production of which is 93 x 106 tonnes) and glucose or glucose-fructose syrups, only relatively small quantities of lactose are produced. However, it attracts commercial interest because it has some interesting properties and is readily available from whey, a by-product in the production of cheese or casein. World production of cheese is c. 1.4 x 107 tonnes, the whey from which contains c. 6 x 106 tonnes of lactose c. 0.3 x 106 tonnes of lactose are contained in the whey produced during casein manufacture. According to Horton (1993),... 

The saccharides have long and awkward names by the IUPAC system, consequently a highly specialized nomenclature system has been developed for carbohydrates. Because this system (and those like it for other natural products) is unlikely to be replaced by more systematic names, you will find it necessary to memorize some names and structures. It will help you to remember the meaning of names such as aldopentose and ketohexose, and to learn the names and details of the structures of glucose, fructose, and ribose. For the rest of the carbohydrates, the nonspecialist needs only to remember the kind of compounds that they are. 

Sweeteners can be classified into two categories, bulk and intense. The bulk sweeteners are used in the food industry both as sweeteners and as bulking agents. They also offer preservative and bodying effect. They are metabolized by the body and provide calories. They include glucose, fructose, maltose, products hydrolyzed from starch, and sugar alcohols. These sweeteners vary in sweetness over a narrow range from 0.3 to 1.2 times the sweetness of sucrose. The bulk sweeteners are permitted in a number of specified foodstuffs at quantum satis—as much as needed (2,6,8-10). 

Fructose syrup. In addition to the glucose/fructose syrups mentioned above, a fructose syrup has been produced using inulin as a source. Inulin is the fructose analogue of starch, and the chicory root is the standard source for commercial hydrolysis. Fructose syrups are usually too expensive for routine use in beverage production but they have been employed where a particular claim is to be made for fructose. They have also been used for the adulteration of fruit juices as they are chemically difficult to detect. Detection is possible at the sub-molecular level by techniques such as stable isotope ratio measurement. Fructose is also manufactured using sucrose as a starting material. 

Because a-dicarbonyl compounds are particularly reactive, Weenen and Apeldoom57 specifically looked for these compounds by means of derivatisation with o-diaminobenzene among the butanol-soluble fragmentation products formed in 15 systems (glucose, fructose, xylose, 3-deoxyglucosone, or fructosylalanine without amine or with alanine or cyclohexylamine 1 h, 100 °C, phosphate buffer, pH 8). Four a-dicarbonyls were obtained glyoxal, 2-oxopropanal, butanedione, and 2,3-pentanedione. 

Martinez et al. (1963) reported that L. brevis fermented lmol fructose to 0.67 mol mannitol and 0.33 mol lactate and 0.33 mol acetate. Soetaert et al. (1995) reported a fed batch fermentation method with automatic feeding strategy for very fast and rapid production of mannitol and D-lactic acid from fructose or glucose/fructose mixture (1 2) by using Leu. pseudomesenteroides. The maximal volumetric productivity of mannitol was 11.1 g/L-h with a final concentration of 150 g/L in 24 h and a conversion efficiency of 94%. By using a special mutant strain, quantitative conversion and a further concentration increase up to 185 g mannitol per L could be obtained. Grobben et al. (2001)... 

Excess glucose can enter the polyol pathway, where it is reduced to sorbitol (by aldose reductase and the reductant NADPH). Sorbitol dehydrogenase will oxidise sorbitol to fructose, which also produces NADH from NAD+. Hexokinase will return fructose to the glycolysis pathway by phosphorylating it to fructose-6-phosphate. However, in uncontrolled diabetics with high blood glucose, the production of sorbitol is favoured. 

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