Lactitol

Fig. 3. Structures of disaccharide alcohols (a) maltitol, (b) lactitol, (c) a-D-glucopyraiiosyl-l,l-D-maiinitol(dihydrate), and (d)...

Lactitol (4-0-p -D-galactopyranosyl-D-glucitol) is obtained by sodium borohydride reduction (99,100) or catalytic hydrogenation (101) of lactose. Potentially large quantities of this sugar alcohol are available from lactose obtained from whey. 

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). 

Sweetness is often an important characteristic of sugar alcohols in food and pharmaceutical applications. The property of sweetness is measured in a variety of ways and has a corresponding variability in ratings (218). Based on one or more test methods, erythritol and xyfitol are similar to or sweeter than sucrose (218,219). Sorbitol is about 60% as sweet as sucrose, and mannitol, D-arabinitol, ribitol, maltitol, isomalt, and lactitol are generally comparable to sorbitol (see Sweeteners). 

Maltitol, lactitol, isomalt, maltitol solutions (symps), and hydrogenated starch hydrolysates (HSH) have GRAS petitions filed with the FDA and are being sold commercially under self-determined GRAS status. Maltitol, owing to its lower negative heat of solution, is often preferred over mannitol as the... 

Arabinitol, galactitol, sorbitol, mannitol, xylitol, lactitol, etc. 

Figure 8.8 Internal mass transfer resistance and catalyst deactivation concentration profiles inside a catalyst particle-lactose hydrogenation to lactitol and by-products (sponge Ni).

Fig. 19.—Possible Hydrogen-bonding in Lactitol. [Key —, possible hydrogen-bond.]...

Very precise kinetic experiments were performed with sponge Ni and Ru/C catalysts in a laboratory-scale pressurized slurry reactor (autoclave) by using small catalyst particles to suppress internal mass transfer resistance. The temperature and pressure domains of the experiments were 20-70 bar and 110-130°C, respectively. Lactitol was the absolutely dominating main product in all of the experiments, but minor amounts of lactulose, lactulitol, lactobionic acid, sorbitol and galactitol were observed as by-products on both Ni and Ru catalysts. The selectivity of the main product, lactitol typically exceeded 96%. 

Figure 12.2. Reaction scheme (1-3, 4b) for formation of lactitol and by-products.

Some data fitting results are displayed in Figures 12.1 and 12.3. The general conclusion is that both models describe the behaviours of the main components, lactose and lactitol very well, both for sponge nickel and ruthenium catalysts. In this respect, no real model discrimination is possible. Both models also describe equally well the behaviour of lactobionic acid (D), including its concentration maximum when the reversible step is included (ks) (Figure 12.3). 

Figure 12.3. Lactose hydrogenation at 120°C and 50 bar on Ru/C (main product lactitol, by-product with maximum lactulose). Fit of model (1-3, 4b).

Hydrogenation of lactose to lactitol on sponge itickel and mtheitium catalysts was studied experimentally in a laboratory-scale slurry reactor to reveal the true reaction paths. Parameter estimation was carried out with rival and the final results suggest that sorbitol and galactitol are primarily formed from lactitol. The conversion of the reactant (lactose), as well as the yields of the main (lactitol) and by-products were described very well by the kinetic model developed. The model includes the effects of concentrations, hydrogen pressure and temperature on reaction rates and product distribution. The model can be used for optinuzation of the process conditions to obtain highest possible yields of lactitol and suppressing the amounts of by-products. 

P. Linko, Lactose and Lactitol, Nntritive Sweeteners, eds. Birch, G. Parker, K., Applied Science NJ, 1982, p.l09. 

Marotta F, Geng TC, Wu CC, Barbi G Bacterial translocation in the course of acute pancreatitis Beneficial role of nonabsorbable antibiotics and lactitol enemas. Digestion 1996 57 446-452. 

Both dietary and endogenous ammoniagenic substrates are removed from the intestinal lumen by the osmotic cathartic action of nonabsorbable disaccharides such as lactulose and lactitol. These compounds are currently the main therapeutic agents for chronic HE. The efficacy of oral lactulose for the treatment of HE has been established in controlled trials [41-43]. Besides having a cathartic effect, lactulose lowers the colonic pH as a result of the production of organic acids by bacterial fermentation. The decrease in pH creates an environment that is hostile to the survival of urease-producing intestinal bac-... 

Loguercio et al. 61 Rif + sorbitol Rif + lactitol Lactitol (double-blind) 14 consecutive days each month for 3 months Mental status, asterixis, blood NH3, number connection test E Rif + Lat = Rif + Sor >Lat T Rif + Lat = Rif + Sor = Lat... 

Mas et al. 62 Lactitol (double-blind) 5-10 days HE index, mental status, asterixis, NH3, number connection test, EEG E Rif >Lat T Rif = Lat... 

Lanthier PL, Morgan MY Lactitol in the treatment of chronic hepatic encephalopathy An open comparison with lactulose. Gut 1985 26 415-420. 

Mas A, Rodes J, Sunyer L, Rodrigo L, Planas R, Vargas V, Castells L, Rodriguez-Martinez D, Fernandez-Rodriguez C, Coll I, Pardo A Comparison of rifaximin and lactitol in the treatment of acute hepatic encephalopathy Results of a randomized, double-blind, doubledummy, controlled clinical trial. J Hepatol 2003 38 51-58. 

After the submission of the manuscript three interesting papers [1-3] dealing with the management of hepatic encephalopathy have been published. A Cochrane systematic review [1] evaluating 30 randomized controlled trials did conclude that antibiotics appear to be superior to nonabsorbable disaccharides in improving symptoms of portal systemic encephalopathy. The authors also emphasized that there is insufficient high-quality evidence to support the use of lactulose or lactitol. A combination of a disaccharide and an antibiotic has been suggested, but not consistently demonstrated to be beneficial [2]. Finally, the use of probiotics has been proposed [3], whose administration could actually follow that of antibiotics. 

Lactide polymers, manufacture of, 14 122 Lactisole, 24 246 Lactitol, 12 40 Lactobacillic acid, 5 36t Lactobacillus, 12 478 Lactococcus, 12 478 Lactoferrins, 18 258 Lactones, 10 497 12 663-664 aroma chemicals, 3 256 in beer, 3 582t Lactonitrile, 8 174 Lactonization, 10 499... 

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