Glucose separation from fructose

Fructose can be separated from glucose by using a liquid membrane with a similar boronic acid in microp-orous polypropylene." When glucose isomerase is included in the liquid, the output can be more than 80% fructose. High-fructose corn syrup is used widely as a sweetener. 

Production of crystallized fructose is rather problematic because of the high solubility of f Starting from high-fructose syrups or from - invert sugar, enrichment of f. is performed by cyclical or continuous chromatographic separation from glucose. F. contents of 85-96% and 90% of d.s. are necessary for crystallization. The process can be either batch or continuous. 

Biologically formed D-glucosone phosphate has been separated from d-glucosone by paper chromatography, using ethyl acetate-amyl alcohol-formamide (1 2 3) as developer. This solvent mixture does not completely separate D-glucosone phosphate from D-glucose 6-phosphate and D-fructose 1-phosphate.16... 

Before glycolysis from glucose can begin, glucose has to be transported into the ceU. This is achieved by a transporter protein, in the plasma membrane (Chapter 5). There are five different types of glucose transporter, all encoded by separate genes. The proteins have slightly different properties, different tissue distribution and somewhat different roles in these tissues. Their roles are briefly described in Table 6.1. A sixth transporter is specific for fructose it is... 

As with all methods, this approach has some limitations it uses acetonitrile, which is toxic, and the separation of glucose from fructose can sometimes be problematic after extended use of the column. However, sample preparation is easy since it requires only dilution to the required level (often 1 10) and filtration prior to analysis to remove particulate materials, which protects and extends the useful life of the column. The degradation of the resolution between glucose and fructose is caused by the partial inactivation of the column by materials in the matrix, but this resolution can be recovered by reducing the acetonitrile concentration in the solvent. The same column can also be used to assay the level of ascorbic acid (vitamin C) in a soft drink or fruit juice, although different detection and solvent systems are used. 

Since Amadori compounds are secondary amines, the question of the formation and reactivity of /V-nitroso derivatives arises. Accordingly, Pool el al 22 tested those derived from glucose with Ala, Asp, Phe, Gly, Ser, and Try in five strains of S. typhimurium with and without S9. The first three compounds were not mutagenic, the next two showed low but reproducible increases in the number of his+ revertants in TA1535 (without S9), but the last, containing indolyl-nitrosamine-D-fructose-L-tryptophan, was mutagenic in all five strains, with and without S9. When separated, the Try compound was mutagenic in three strains, without S9. 

International classification C12P19/14, C13K11/00, C12P19/00 A method for producing high-fructose syrup from Jerusalem artichoke tubers is disclosed. Inulin is extracted in water and subject to enzymatic hydrolyses to fructose and glucose. The sugars are separated, ultrafiltrated, and evaporated. The fructose syrup (at least 90% dry wt) can be mixed with fructose com syrup in food applications. 

The separation of fructose from glucose illustrates the interaction between the framework structure and the cation (Fig. 5) (50). Ca2+ is known to form complexes with sugar molecules such as fructose. Thus, Ca —Y shows a high selectivity for fructose over glucose. However, Ca—X does not exhibit high selectivity. On the other hand, K—X shows selectivity for glucose over fructose. This polar nature of faujasites and their unique shape-selective properties, more than the molecular-sieving properties, make them most useful as practical adsorbents. 

Polymeric cation-excliange resins are also used in the separation of fructose from glucose. The UOP Sarex process has employed both zeolitic and polymeric resin adsorbents for the production of high fructose com syrup (HFCS). The operating characteristics of these two adsorbents are substantially different and have been compared in terms of fundamental characteristics such as capacity, selectivity, and adsorption kinetics (51). 

Fructose—Dextrose Separation. Fructose—dextrose separation is an example of the application of adsorption to nonhydrocarbon systems. An aqueous solution of the isomeric monosaccharide sugars, C(5H120(5, fructose and dextrose (glucose), accompanied by minor quantities of polysaccharides, is produced commercially under the designation of "high11 fructose com syrup by the enzymatic conversion of cornstarch. Because fructose has about double the sweetness index of dextrose, the separation of fructose from this mixture and the recycling of dextrose for further enzymatic conversion to fructose is of commercial interest (see Sugar Sweeteners). 

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