Dextrose, purification

Application of ion exchange to the manufacture of dextrose has been in the process of development for several years. Numerous problems, not present in the application of ion exchange to water purification, were met which required solution. Although some problems remain,... 

The application of ion exchangers to dextrose process liquors involved considerable experimental work because of a number of factors which do not enter into their application to water purification. The accumulation of fats and proteins on the resin surfaces must be guarded against by proper clarification of the liquors to be treated. Such accumulation may result from precipitation as the neutralization progresses, and may soon destroy the effective acid-removing capacity of the anion exchange resin. This difficulty can effectively be eliminated by prior precipitation of thfe refinery residue from the acid liquor by bentonite, a colloidal clay of opposite electrical charge to the colloids,21 followed by filtration. 

The biodegradable polymer available in the market today in largest amounts is PEA. PEA is a melt-processible thermoplastic polymer based completely on renewable resources. The manufacture of PEA includes one fermentation step followed by several chemical transformations. The typical annually renewable raw material source is com starch, which is broken down to unrefined dextrose. This sugar is then subjected to a fermentative transformation to lactic acid (LA). Direct polycondensation of LA is possible, but usually LA is first chemically converted to lactide, a cyclic dimer of LA, via a PLA prepolymer. Finally, after purification, lactide is subjected to a ring-opening polymerization to yield PLA [13-17]. 

Dextrose and sorbitol undergo a catalytic condensation reaction with an acid. Further purification may be performed to... 

In order to purify the RBCs, the plasma and huffy coat (white cells) are removed for further purification (see above). RBCs are then resuspended and washed three times in a physiological salt solution [PSS in mM, 4.7 KCl, 2.0 CaCh, 140.5 NaCl, 12 MgS04,21.0 tris(hydroxymethyl)aminomethane, 11.1 dextrose with 5% bovine serum albumin (final pH 7.4)]. Cells should generally be prepared and studied on the day of use within 8 h of removal from animal or human subjects. 

The process is based on fermentation of a dextrose-based feedstock such as corn starch, with three key advantages greater elficiency by reducing the number of steps in the conventional process electrically driven advanced membrane separation stage, eliminating an undesirable salt by-product patented purification-separation system (seen as the key to the economics of the process). 

In the sugar industry, NF is used for concentration of dextrose symp originating from starch and for demineralization of colored brine from anion exchange resin elution solutions (Bargeman et al., 2005). The purification of alternative (low-calorie) sweeteners such as stevioside might also require a nanofiltration step (Zhang et al., 2000). 

After purification, the syrup is made up to 75% d.s. Higher enrichment of branched oligosaccharides (%85% d.s.) by separation from the dextrose is achieved by cation-exchange-resin chromatography. 

The method of c. is also frequently used in purification and separation in the sugar processing industry (e.g., -+sugar beet processing, - sugar cane processing ->dextrose). 

The term d. is also used for the pure, chemically defined product, obtained by the complete hydrolysis of starch (or cellulose), followed by purification and crystallization. It is to be discerned from the industrial product - glucose syrups (frequently abbreviated termed as glucose ), which contain dextrose as the main sugar within samples of low molecular - starch hydrolysis products. 

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