Polyol mannitol

Lyoprotectants can affect enzyme stability in both stages of lyophilization the freezing and the drying stages. In the freezing stage of lyophilization, ice crystals form and have been shown to be a cause of enzyme denaturation. Studies have shown that when added as a lyoprotectant, the amorphous polyol mannitol stabi-... 

They include polyols (mannitol, sorbitol, glycerol or pentaerythritol), hindered phenol antioxidants, the dihydropyridines, epoxidised soya bean oil, certain other epoxy compounds such as isooctyl epoxystearate, the alkyl phosphites (triphenyl phosphite, trisnonylphenyl phosphite, tristearyl phosphite or a diphosphite), 1,3-diketones, and the ketocarboxylates. 

Saccharides are the main carbon and energy source for Claviceps both under parasitic and saprophytic conditions. Sucrose is an important component of phloem sap of the host plants (Basset et al., 1972). The best substrates for alkaloid production are slowly metabolizable Saccharides, e.g., sucrose, maltose and polyols (mannitol, sorbitol) (Kfen et al., 1984). 

During a botrytis attack, other polyols (mannitol, erythritol and meso-inositol) are formed and their concentrations increase in the grape (Bertrand et ah, 1976). B. cinerea also produces a glucose polymer, which accumulates in contaminated grapes. Its concentration can attain 200 mg/1 in must. This glucan is often at the root of subsequent wine clarification difficulties (Dubourdieu, 1978). 

Humectants. In certain foods, it is necessary to control the amount of water that enters or exits the product. It is for this purpose that humectants are employed. Polyhydric alcohols (polyols), which include propylene glycol [57-55-6], C2Hg02, glycerol [56-81-5], C HgO, sorbitol [50-70-4], and mannitol [69-65-8], contain numerous hydroxyl groups (see Alcohols,polyhydric). Their stmcture makes them hydrophilic and... 

Etherification. The reaction of alkyl haUdes with sugar polyols in the presence of aqueous alkaline reagents generally results in partial etherification. Thus, a tetraaHyl ether is formed on reaction of D-mannitol with aHyl bromide in the presence of 20% sodium hydroxide at 75°C (124). Treatment of this partial ether with metallic sodium to form an alcoholate, followed by reaction with additional aHyl bromide, leads to hexaaHyl D-mannitol (125). Complete methylation of D-mannitol occurs, however, by the action of dimethyl sulfate and sodium hydroxide (126). A mixture of tetra- and pentabutyloxymethyl ethers of D-mannitol results from the action of butyl chloromethyl ether (127). Completely substituted trimethylsilyl derivatives of polyols, distillable in vacuo, are prepared by interaction with trim ethyl chi oro s il an e in the presence of pyridine (128). Hexavinylmannitol is obtained from D-mannitol and acetylene at 25.31 MPa (250 atm) and 160°C (129). 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

Separated polyols are detected by a variety of reagents, including ammoniacal silver nitrate (175), concentrated sulfuric acid, potassium permanganate (163), lead tetraacetate, and potassium teUuratocuprate (176). A mixture of sodium metaperiodate and potassium permanganate can be used to detect as htde as 5—8 ).tg of mannitol or erythritol (177). 

Conversion to acetates, trifluoroacetates (178), butyl boronates (179) trimethylsilyl derivatives, or cycHc acetals offers a means both for identifying individual compounds and for separating mixtures of polyols, chiefly by gas—Hquid chromatography (glc). Thus, sorbitol in bakery products is converted to the hexaacetate, separated, and determined by glc using a flame ionisation detector (180) aqueous solutions of sorbitol and mannitol are similarly separated and determined (181). Sorbitol may be identified by formation of its monobensylidene derivative (182) and mannitol by conversion to its hexaacetate (183). 

The 1995 Canadian and United States sugar alcohol (polyol) production is shown in Table 2. The market share of each is also given. Liquids comprise 48% crystalline product comprises 39% and mannitol comprises 13% of the polyol market. An estimate of total U.S. sorbitol capacity for 1995 on a 70% solution basis was 498,000 t. ADM, Decatur, lU., produced 68,200 t Ethichem, Easton, Pa., 13,600 t Lon2a, Mapleton, lU., 45,400 t Roquette America, Gurnee, lU., 68,200 t and SPI Polyols, New Castle, Del., 75,000 t (204). Hoffman-LaRoche, which produces sorbitol for captive usage in the manufacture of Vitamin C (see Vitamins), produced about 27,300 t in 1995. 

Addition of secondary chelating agents, eg, polyols such as sorbitol or mannitol and the strongly chelating a-hydroxycarboxyhc acids such as citric or oxahc, prevents development of turbidity outside the pH range of 9—11 (115—117). 

Reduction. Mono- and oligosaccharides can be reduced to polyols (polyhydroxy alcohols) termed alditols (glycitols) (1) (see Sugar alcohols). Common examples of compounds in this class ate D-glucitol (sorbitol) [50-70-4] made by reduction of D-glucose and xyhtol [87-99-0] made from D-xylose. Glycerol [56-87-5] is also an alditol. Reduction of D-fmctose produces a mixture of D-glucitol and D-mannitol [69-65-8],... 

Nonionic Surface-Active Agents. Approximately 14% of the ethyleae oxide consumed ia the United States is used in the manufacture of nonionic surfactants. These are derived by addition of ethylene oxide to fatty alcohols, alkylphenols (qv), tall oil, alkyl mercaptans, and various polyols such as poly(propylene glycol), sorbitol, mannitol, and cellulose. They are used in household detergent formulations, industrial surfactant appHcations, in emulsion polymeri2ation, textiles, paper manufacturing and recycling, and for many other appHcations (281). 

Hydrogenated starch hydrosylate is a mixture of several polyols, or sugar alcohols, such as sorbitol, maltitol, and mannitol, among others. 

Initially, attempts to grow the organism on sodium acetate as the sole source of carbon were unsuccessful, but the difficulties were overcome and mannitol, arabinitol, erythritol, glycerol, maltose, and a,a-trehalose were produced. This was a useful development because conditions were established for the incorporation of [14C] acetate, thereby making labeled polyols and disaccharides available. 

Accumulation of compatible solutes (glycine betaine, proline and polyols such as mannitol, sorbitol and pinitol) occurs in many droughted plants and they act as cytoplasmic osmotica for osmotic adjustment. However, they may have other functions which include enhancing the stability of macromolecules and membranes (Paleg, Stewart Starr, 1985 Smirnoff Stewart, 1985 Chapter 7). 

Boron zirconimn chelates from ammonium hydroxide water-soluble amines sodium or potassimn zirconium and organic acid salts such as lactates, citrates, tartrates, glycolates, malates, gluconates, glycerates, and mandelates with polyols such as glycerol, erythritol, arabitol, xylitol, sorbitol, dulcitol, mannitol, inositol, monosaccharides, and disaccharides [463,464,1592,1593]... 

Glycerol, polyols (sorbitol, mannitol) Solvophobicity Affinity for polar regions Stabilizers of globular proteins and assembled organelles, decreasing for proteins of high polarity... 

Several polyols (i.e. molecules displaying multiple hydroxyl groups) have found application as polypeptide stabilizing agents. Polyols include substances such as glycerol, mannitol, sorbitol and PEG, as well as inositol (Table 6.9 and Figure 6.22). A subset of polyols is the carbohydrates, which are listed separately (and thus somewhat artificially) from polyols in Table 6.9. Various polyols have been found to stabilize proteins in solution directly, and carbohydrates in particular are also often added to biopharmaceutical products prior to freeze-drying in order to provide physical bulk to the freeze-dried cake. 

Creighton An electrolytic process for reducing sugars to their corresponding polyols. Glucose is thus reduced to sorbitol, mannose to mannitol, and xylose to xylitol. The electrodes are made of amalgamated lead or zinc the electrolyte is sodium sulfate. Invented in 1926 by H. J. Creighton. 

Japanese workers have described a stable aqueous solution of neomycin with the incorporation of a borate buffer (pH 6) and E.D.T.A.295 The presence of 1-10% of glycerol, propylene glycol or mannitol has been claimed to improve the solution appearance by preventing discoloration29°. The presence of polyols also prevented a decrease in pH value of the solution. Discoloration may also be prevented by addition of 0.1% sodium metabisulphite at a solution pH of 6.6 to 6.8297. 

Different preparative procedures have been shown to yield protein fractions which are able to catalyze different types of reactions with respect to their requirement of either NAD or NADP as coenzymes [cf. Eqs. (19), (20), and (21)]. In sera of mice poisoned by carbon tetrachloride we found polyol dehydrogenases catalyzing the oxidation of the following polyols (a) with NAD sorbitol, ribitol, mannitol (b) with NADP sorbitol, ribitol. Erythritol and mt/o-inositol were not attacked at all. Figures 8 and 9 show the results of these determinations performed at pH 9.6. In the NAD system sorbitol and ribitol are oxidized at exactly the same rate, while in the NADP system ribitol does not reach the rate of sorbitol. The ratio NAD NADP for sorbitol is calculated to be 4.20 and for ribitol 5.50. Mannitol is oxidized at 23% of the rate of sorbitol. 

Fic. 8. NAD polyol dehydrogenase in sera of CCl4-poisoned mice sorbitol, ribitol, and mannitol oxidation (pH 9.6 polyols as substrates). 

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