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Xylitol
Terms modified by Xylitol Selected AbstractsBiodegradable Xylitol-Based Polymers,ADVANCED MATERIALS, Issue 10 2008Joost P. Bruggeman Synthetic polymers composed of metabolites endogenous to the mammalian organism are designed. The design is based on the monomer xylitol, which possesses a wide range of physical properties that are biologically relevant. Xylitol-based hydrogels and elastomers are biocompatible in vitro and in vivo, compared to the prevalent synthetic polymer poly(L-lactic- co - glycolic acid) (PLGA). It furthermore provides a platform to tune mechanical properties, degradation profiles, and cell attachment. [source] Effect of oxygen transfer rates on alcohols production by Candida guilliermondii cultivated on soybean hull hydrolysateJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2009Ângela Cristina Schirmer-Michel Abstract BACKGROUND: In this research the use of soybean hull hydrolysate (SHH) as substrate for xylitol and ethanol production using an osmotolerant strain of Candida guilliermondii was studied. The production of alcohols was investigated in batch cultivations in which the variable parameter was the volumetric oxygen mass transfer coefficient (kLa) obtained from three different conditions of air supply: anaerobic (150 rpm, no aeration); microaerobic (300 rpm, 1 vvm), and aerobic (600 rpm, 2 vvm), corresponding to kLa values of 0; 8; and 46 h,1, respectively. RESULTS: SHH, although presenting a very high osmotic pressure (1413 mOsm kg,1), was completely metabolized under aerobic conditions with high biomass productivities of 0.49 g cells (L h),1, with little formation of ethanol. Xylitol was produced under microaeration, with product yield of 0.22 g g,1 xylose, with the formation of glycerol as a by-product. No xylose was metabolized under anaerobic conditions, but ethanol was produced from hexoses with high product yields of 0.5 g g,1. CONCLUSION: These results suggest that the hydrolysis of soybean hull and its conversion to ethanol and other alcohols could be an important use of this agro-industrial waste, which could be used for biofuel, xylitol or biomass production, depending on the aeration conditions of the cultures. Copyright © 2008 Society of Chemical Industry [source] Xylitol inhibition of anaerobic acid production by Streptococcus mutans at various pH levelsMOLECULAR ORAL MICROBIOLOGY, Issue 4 2003H. Miyasawa Xylitol inhibits the glycolysis and growth of Streptococcus mutans. We studied the inhibitory effect of xylitol on the acid production of S. mutans at several pH levels under the strictly anaerobic conditions found in the deep layer of dental plaque. Xylitol inhibited the rate of acid production from glucose and changed the profile of acidic end products to formate,acetate dominance, with a decrease in the intracellular level of fructose 1,6-bisphosphate and an intracellular accumulation of xylitol 5-phosphate (X5P). These results were notable at pH 5.5,7.0, but were not evident at pH 5.0. Since the activity of phosphoenolpyruvate phosphotransferase for xylitol was greater at higher pH, it is suggested that xylitol could be incorporated more efficiently at higher pH and that the resultant accumulation of X5P could inhibit the glycolysis of S. mutans more effectively. [source] Xylitol as a causative agent of oral erosive eczemaBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005Yoshiko Hanakawa No abstract is available for this article. [source] Determination of neutral carbohydrates by CZE with direct UV detectionELECTROPHORESIS, Issue 17 2007Stella Rovio Abstract A new CZE method relying on in-capillary reaction and direct UV detection at the wavelength 270,nm is presented for the simultaneous separation of the neutral carbohydrates xylitol, D -(,)-mannitol, sucrose, D -(+)-fucose, D -(+)-cellobiose, D -(+)-galactose, D -(+)-glucose, L -rhamnose, D -(+)-mannose, D -(,)-arabinose, D -(+)-xylose, and D -(,)-ribose. The alkaline electrolyte solution was prepared of 130,mM sodium hydroxide and 36,mM disodium hydrogen phosphate dihydrate. Separation of the sample mixture was achieved within 35,min. Calibration plots were linear in the range of 0.05,3,mM. Reproducibility of migration times was between 0.3 and 1.1%, and the detection limits for the analytes were 0.02 and 0.05,mM. The optimized method was applied for the determination of neutral monosaccharides in lemon, pineapple, and orange juices and a cognac sample. The methodology is fast since no other sample preparation except dilution is required. [source] Teaching received in caries prevention and perceived need for Best Practice Guidelines among recent graduates in FinlandEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 1 2004Miira M. Vehkalahti The present study evaluated teaching that recent graduates in Finland had received in caries prevention and their perceived need for updated Best Practice Guidelines. A two-page questionnaire was mailed to all dentists in Finland who had graduated from 1995 to 1998 (n = 390). After one reminder, the response rate was 46%. The closed questions covered teaching in 14 caries-preventive methods and its suggestions as to when and on whom to apply such methods. Each dentist's own opinion on the three most important methods for caries prevention in patients with various types of dentition was sought in open questions. The respondents reported that at dental school, on average 12.5 (SD = 2.4) of 14 aspects of caries prevention were covered in theoretical teaching, 5.5 (SD = 3.8) in demonstrations and 8.5 (SD = 3.0) in clinical training. The top four methods teaching suggested for every patient were toothbrushing (100%), use of fluoridated toothpaste (99%), interdental cleaning (98%), and use of xylitol (97%); followed by fluoride varnish (77%) and fissure sealants (54%). The three caries-preventive methods the respondents felt to be most useful were the same for all types of dentitions, in order of importance: (i) toothbrushing and use of fluoridated toothpaste, (ii) supplementary use of fluorides at home and (iii) healthy dietary habits, in particular, avoidance of sucrose. As regards clinical work, such teaching had served the respondents' real-life needs in patients' caries prevention either extremely (44%) or moderately (54%) well; 91% said, however, that they would benefit from nationwide Best Practice Guidelines. In conclusion, the recent graduates' emphasis on patient-active methods in caries prevention may indicate a change in the current policy favouring patient-passive methods. [source] Synthesis of Hybrids of D -Glucose and D -Galactose with Pyrrolidine-Based Iminosugars as Glycosidase InhibitorsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2008Venkata Ramana Doddi Abstract Sugar,iminosugar hybrid molecules made up of D -glucose and D -galactose with pyrrolidine-based iminosugars, viz. 1,4-dideoxy-1,4-imino- L -xylitol and 1,4-dideoxy-1,4-imino- L -lyxitol, are synthesized from glycal epoxides and found to be moderate glycosidase inhibitors. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Adhesion and development of the root rot fungus (Heterobasidion annosum) on conifer tissues: effects of spore and host surface constituentsFEMS MICROBIOLOGY ECOLOGY, Issue 2 2000Frederick O Asiegbu Abstract The objective of this study was to correlate the occurrence of particular root and woody stump surface components with the ability of spores of the root rot fungus (Heterobasidion annosum) to adhere, germinate and establish on conifer tissues. With the aid of high performance liquid chromatography, several sugars (pinitol, xylitol, dulcitol, mannitol, D -glucose, mannose, fructose) were detected on both stump and fine root surfaces of Scots pine and Norway spruce. Of all the sugars observed, xylose and arabinose were poorly utilized for initiation of germ tube growth whereas spore germination was enhanced in the presence of D -glucose, mannose or fructose. Oxidation of these sugars by pretreatment of wood discs or roots with periodic acid abolished the ability of the spores to germinate. Non-sugar components such as long chain fatty acids on spores and root surfaces as detected with nuclear magnetic resonance were found to have a significant influence on adhesion and initiation of germ tube development. Removal of these aliphatic compounds from the root surface increased spore germination by 2-fold, whereas similar treatment on spores led to a 5-fold decrease in adhesiveness to root material. In vitro studies revealed that the di-ethyl ether extract from the roots had no long term adverse effect on spore germination which suggests that the fungus may possess the capability to detoxify this substance. Similarly, adhesion of spores was affected by low and freezing temperatures. The role of significant levels of mannitol and trehalose accumulated in spores and hyphae of the fungi on viability, survival and tolerance to adverse conditions such as oxidative stress, freezing and desiccation are discussed. [source] Bioconversions of maize residues to value-added coproducts using yeast-like fungi,FEMS YEAST RESEARCH, Issue 2 2003Timothy D Leathers Abstract Agricultural residues are abundant potential feedstocks for bioconversions to industrial fuels and chemicals. Every bushel of maize (approximately 25 kg) processed for sweeteners, oil, or ethanol generates nearly 7 kg of protein- and fiber-rich residues. Currently these materials are sold for very low returns as animal feed ingredients. Yeast-like fungi are promising biocatalysts for conversions of agricultural residues. Although corn fiber (pericarp) arabinoxylan is resistant to digestion by commercially available enzymes, a crude mixture of enzymes from the yeast-like fungus Aureobasidium partially saccharifies corn fiber without chemical pretreatment. Sugars derived from corn fiber can be converted to ethanol or other valuable products using a variety of naturally occurring or recombinant yeasts. Examples are presented of Pichia guilliermondii strains for the conversion of corn fiber hydrolysates to the alternative sweetener xylitol. Corn-based fuel ethanol production also generates enormous volumes of low-value stillage residues. These nutritionally rich materials are prospective substrates for numerous yeast fermentations. Strains of Aureobasidium and the red yeast Phaffia rhodozyma utilize stillage residues for production of the polysaccharide pullulan and the carotenoid astaxanthin, respectively. [source] Biodegradable Xylitol-Based Polymers,ADVANCED MATERIALS, Issue 10 2008Joost P. Bruggeman Synthetic polymers composed of metabolites endogenous to the mammalian organism are designed. The design is based on the monomer xylitol, which possesses a wide range of physical properties that are biologically relevant. Xylitol-based hydrogels and elastomers are biocompatible in vitro and in vivo, compared to the prevalent synthetic polymer poly(L-lactic- co - glycolic acid) (PLGA). It furthermore provides a platform to tune mechanical properties, degradation profiles, and cell attachment. [source] Ingredients in dentifrices and their effect on plaque, gingivitis and mutans streptococciINTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 1 2004L Jannesson The main objectives of this thesis were to study: (i) the effect of an enzyme-containing dentifrice (Zendium Dentine®), with addition of xylitol on mutans streptococci (MS) in saliva and dental plaque (Paper I) (ii) the effect of a combination of triclosan and xylitol in a dentifrice (Colgate Total®) on MS in saliva and dental plaque (Paper II), and (iii) the effect of oxybenzone on prostaglandin E2 (PGE2)-production in cell culture and the effect of an oxybenzone-containing dentifrice on plaque, gingivitis and MS (Paper III). In Paper I, the subjects were divided into two test groups: one using a 10% xylitol and the other using a 5% xylitol dentifrice for 3 months. The addition of 10% xylitol to Zendium Dentine® had an inhibitory effect on MS in both saliva and dental plaque, and the effect of xylitol seemed to be dose dependent. In Paper II, three groups were using one of the following dentifrices: (i) Colgate Total® with addition of 10% xylitol; (ii) Colgate Total®; and (iii) Colgate Total® without triclosan and without xylitol. The results showed that the addition of 10% xylitol to Colgate Total® reduced the number of MS in saliva and plaque. This effect was more pronounced at 6 months than at 2 months. In Paper III, the effect of oxybenzone was studied in vitro and in vivo. Human Embryo Palatal Mesenchyme (HEPM) cells were used to test the inhibition of IL-1,-stimulated PGE2 production by different concentrations of oxybenzone. The results revealed that there was no decrease of cell viability up to 50 µm. A dose-dependent inhibition of stimulated PGE2 production was found: 50% inhibition (IC50) was found at 0.6 µm. Paper III also included a double-blind clinical trial testing two fluoride dentifrices: one with the addition of 0.5% oxybenzone and one without. Plaque index was reduced in both groups. There was no difference between the groups. A 25% reduction in gingival index was observed in the oxybenzone group after 6 weeks, compared to 2% in the placebo group, indicating an anti-inflammatory effect of oxybenzone. [source] Effect of xylitol and xylitol,fluoride lozenges on approximal caries development in high-caries-risk childrenINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 3 2008CHRISTINA STECKSÉN-BLICKS Aim., To evaluate the effect of xylitol- and xylitol/fluoride-containing lozenges on approximal caries development in young adolescents with high caries risk. Study design., A 2-year double-blind trial with two parallel arms and a nonrandomized reference group. Material and methods., One hundred and sixty healthy 10- to 12-year-old children with high caries risk were selected. After informed consent, they were randomly assigned into a xylitol and a xylitol/fluoride group. They were instructed to take two tablets three times a day (total xylitol and fluoride dose 2.5 g and 1.5 mg, respectively). The compliance was checked continuously and scored as good, fair, or poor. A reference no-tablet group was also selected (n = 70) for group comparison. The outcome measure was approximal caries incidence. Results., The dropout rate was 28%, and 41% exhibited a good compliance with the study protocol. No statistically significant differences in caries incidence could be found between the study groups (P > 0.05). Among a subgroup of children who demonstrated good compliance, the mean ,DMFSa value was significantly lower in the xylitol/fluoride group compared to the xylitol group, 1.0 ± 2.3 vs. 3.3 ± 4.6 (P < 0.05), while no difference could be displayed between any of the study groups and the reference group (P > 0.05). Conclusion., The results from this 2-year trial did not support a self-administered regimen of xylitol- or xylitol/fluoride-containing lozenges for the prevention of approximal caries in young adolescents with high caries risk. [source] Effects of cryoprotectant concentration and cooling rate on vitrification of aqueous solutionsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2006Naji S. Husseini Vitrification of aqueous cryoprotectant mixtures is essential in cryopreservation of proteins and other biological samples. Systematic measurements of critical cryoprotective agent (CPA) concentrations required for vitrification during plunge-cooling from T = 295,K to T = 77,K in liquid nitrogen are reported. Measurements on fourteen common CPAs, including alcohols (glycerol, methanol, 2-propanol), sugars (sucrose, xylitol, dextrose, trehalose), polyethylene glycols (ethylene glycol, PEG 200, PEG 2000, PEG 20000), glycols [dimethyl sulfoxide (DMSO), 2-methyl-2,4-pentanediol (MPD)], and salt (NaCl), were performed for volumes ranging over four orders of magnitude from ,1,nl to 20,µl, and covering the range of interest in protein crystallography. X-ray diffraction measurements on aqueous glycerol mixtures confirm that the polycrystalline-to-vitreous transition occurs within a span of less than 2% w/v in CPA concentration, and that the form of polycrystalline ice (hexagonal or cubic) depends on CPA concentration and cooling rate. For most of the studied cryoprotectants, the critical concentration decreases strongly with volume in the range from ,5,µl to ,0.1,µl, typically by a factor of two. By combining measurements of the critical concentration versus volume with cooling time versus volume, the function of greatest intrinsic physical interest is obtained: the critical CPA concentration versus cooling rate during flash-cooling. These results provide a basis for more rational design of cryoprotective protocols, and should yield insight into the physics of glass formation in aqueous mixtures. [source] An in vitro study of the pH-lowering potential of salivary lactobacilli associated with dental cariesJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2001M.C. Badet M.C. BADET, B. RICHARD AND G. DORIGNAC. 2001. Aims: Lactobacilli are known to produce acids from sucrose or glucose. This acid production can cause a drop in pH which is sufficiently significant to demineralize the hard tissues of the teeth. Some authors have demonstrated the benefits of substituting sorbitol or xylitol for sucrose. The aim of this work was to study the acid production of salivary lactobacilli with one test sugar (glucose) and two polyols (sorbitol and xylitol). Methods and Results: The pH-lowering potential of three strains of oral lactobacilli was recorded with glucose or one of the polyols at three different concentrations. The results showed that polyols were broken down by certain strains of lactobacilli. When this degradation took place, the pH dropped to values sufficiently low to demineralize the hard tissues of the teeth. Conclusions: Further studies must be carried out on the metabolism of polyols before encouraging their widespread substitution for sucrose. [source] Competitive plasticization in ternary plasticized starch biopolymer systemJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2010Deeptangshu S. Chaudhary Abstract Two plasticizers namely, glycerol and xylitol, based on their similar molecular diameter (, 6.3 Ĺ) but different molecular weights (glycerol-92; xylitol-152) were selected were selected for studying the plasticization of starch biopolymer containing 70% amylopectin structure via glass transition measurements carried over a wide range of water activity. A standard calorimetry was used to determine the onset temperature of polymeric viscous flow. For both glycerol and xylitol, typical antiplasticization was evident at low plasticizer concentrations, whereas at higher concentration, there was significant reduction in glass transition temperature. Water activity isotherms showed that equilibrium moisture content of the starch biopolymer (no plasticizer) steadily increases up to 11%, however, for plasticized biopolymer, the moisture content was nearly double than that of biopolymer. We used a modified Gordon-Taylor model, using a new interaction parameter, to understand the competitive plasticization of glycerol and xylitol in presence of water, and determined 8 wt % water as a threshold amount of matrix water for strong three-way interactions: starch-plasticizer, plasticizer-plasticizer/water and starch-water. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Antihyperlipidemic activity of 3-hydroxymethyl xylitol, a novel antidiabetic compound isolated from Casearia esculenta (Roxb.) root, in streptozotocin-diabetic ratsJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2010Govindasamy Chandramohan Abstract Casearia esculenta root (Roxb.) is widely used in traditional system of medicine to treat diabetes in India. An active compound, 3-hydroxymethyl xylitol (3-HMX), has been isolated, and its optimum dose has been determined in a short duration study and patented. In addition, the long-term effect of 3-HMX in type 2 diabetic rats on carbohydrate metabolism was investigated, and its antihyperglycemic effect was shown previously (Chandramohan et al., Eur J Pharmacol 2008;590:437,443). In this study we investigated the effect of 3-HMX on plasma and tissue lipid profiles in streptozotocin-induced diabetic rats. Diabetes was induced in adult male albino rats of the Wistar strain, weighing 180,200 g, by administration of streptozotocin (40 mg/kg of body weight) intraperitoneally. The normal and diabetic rats were treated with 3-HMX (40 mg/kg BW/day) for 45 days. The levels of total cholesterol, triglycerides, free fatty acids, and phospholipids were assayed in the plasma besides lipoprotein-cholesterol (high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and very low density lipoprotein-cholesterol (VLDL-C)) and tissues (liver, kidney, heart, and brain). Total cholesterol, triglyceride, free fatty acid, and phospholipid (LDL-C and VLDL-C in plasma only) levels increased in plasma and tissues significantly, whereas plasma HDL-C significantly decreased in diabetic rats. Treatment with 3-HMX or glibenclamide reversed the above-mentioned changes and improved toward normalcy. Histological study of liver also confirmed the biochemical findings. Thus administration of 3-HMX is able to reduce hyperglycemia and hyperlipidemia related to the risk of diabetes mellitus. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:95,101, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20317 [source] Batch cooling crystallization of xylitol produced by biotechnological routeJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2009Ernesto Acosta Martínez Abstract BACKGROUND: This work deals with the xylitol production by biotechnological routes emphasizing the purification process using crystallization. RESULTS: Xylitol volumetric productivity of 0.665 g L,1 h,1 and yield of 0.7024 g g,1 were obtained after 92 h fermentation. The fermented broth (61.3 g L,1 xylitol) was centrifuged, treated and concentrated obtain a syrup (745.3 g L,1 xylitol) which was crystallized twice, xylitol crystals with 98.5,99.2% purity being obtained. CONCLUSION: The hypothetical distribution obtained permits the determination of modeling parameters, which make possible the estimation of crystal dominant size from different initial experimental conditions. Copyright © 2008 Society of Chemical Industry [source] Fermentation of enzymatic hydrolysates from olive stones by Pachysolen tannophilusJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2009Manuel Cuevas Abstract BACKGROUND: Olive stones were pretreated with liquid hot water (LHW or autohydrolysis) at maximum temperatures between 175 and 225 °C (severity factors, logR0, between 2.73 and 4.39) to be subjected (both liquid and solid components) afterwards to enzymatic hydrolysis with cellulases from Trichoderma viride. Ethanol fermentation of hydrolysates was performed with the non-traditional yeast Pachysolen tannophilus ATCC 32691. RESULTS: After the enzymatic step, yields of hemicellulose solubilization reached 100%, while the cellulose was only partially hydrolysed (23%, logR0 = 4.39). The maximum yields in total reducing sugars and acetic acid, at the upper end of the severity range, was close to 0.25 and 0.04 g g,1 dry stone, respectively. During the fermentation stage, the increase in R0 reduced the maximum specific growth rate, biomass productivity, and overall biomass yield. The overall yields of ethanol and xylitol ranged, respectively, from 0.18 to 0.25 g g,1 and from 0.01 to 0.13 g g,1. CONCLUSIONS: The results demonstrate the possibility of producing ethanol from olive stones, making use of the cellulose and hemicellulose fraction of the waste. It was confirmed that the overall yield in xylitol strongly depended on severity factor, while the overall yield in ethanol remained practically constant for all the pretreatment conditions tested. Copyright © 2008 Society of Chemical Industry [source] Effect of oxygen transfer rates on alcohols production by Candida guilliermondii cultivated on soybean hull hydrolysateJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2009Ângela Cristina Schirmer-Michel Abstract BACKGROUND: In this research the use of soybean hull hydrolysate (SHH) as substrate for xylitol and ethanol production using an osmotolerant strain of Candida guilliermondii was studied. The production of alcohols was investigated in batch cultivations in which the variable parameter was the volumetric oxygen mass transfer coefficient (kLa) obtained from three different conditions of air supply: anaerobic (150 rpm, no aeration); microaerobic (300 rpm, 1 vvm), and aerobic (600 rpm, 2 vvm), corresponding to kLa values of 0; 8; and 46 h,1, respectively. RESULTS: SHH, although presenting a very high osmotic pressure (1413 mOsm kg,1), was completely metabolized under aerobic conditions with high biomass productivities of 0.49 g cells (L h),1, with little formation of ethanol. Xylitol was produced under microaeration, with product yield of 0.22 g g,1 xylose, with the formation of glycerol as a by-product. No xylose was metabolized under anaerobic conditions, but ethanol was produced from hexoses with high product yields of 0.5 g g,1. CONCLUSION: These results suggest that the hydrolysis of soybean hull and its conversion to ethanol and other alcohols could be an important use of this agro-industrial waste, which could be used for biofuel, xylitol or biomass production, depending on the aeration conditions of the cultures. Copyright © 2008 Society of Chemical Industry [source] The fermentation of mixtures of D -glucose and D -xylose by Candida shehatae, Pichia stipitis or Pachysolen tannophilus to produce ethanolJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002Sebastián Sánchez Abstract The fermentation of mixtures of D -glucose and D -xylose by three non-traditional yeasts: Candida shehatae (ATCC 34887), Pachysolen tannophilus (ATCC 32691) and Pichia stipitis (ATCC 58376) have been studied to determine the optimal strain and initial culture conditions for the efficient production of ethanol. The comparison was made on the basis of maximum specific growth rate (µm), biomass productivity, the specific rates of total substrate consumption (qs) and ethanol production (qE) and the overall yields of ethanol and xylitol. All the experiments were performed in stirred-tank batch reactors at a temperature of 30,°C. The initial pH of the culture medium was 4.5. The highest values of µm (above 0.5,h,1) were obtained with P stipitis in cultures containing high concentrations of D -xylose. All three yeasts consumed the two monosaccharides in sequence, beginning with D -glucose. The values of qs diminished during the course of each experiment with all of the yeasts. The highest values of the specific rates of total substrate consumption and ethanol production were obtained with C shehatae (for t,=,10,h, qs and qE were above 5,g,g,1,h,1 and 2,g,g,1,h,1, respectively), although the highest overall ethanol yields were fairly similar with all three yeasts, at around 0.4,g,g,1. © 2002 Society of Chemical Industry [source] Mechanical Properties, Water Vapor Permeabilities and Solubilities of Highly Carboxymethylated Starch-Based Edible FilmsJOURNAL OF FOOD SCIENCE, Issue 1 2002K.W. Kim ABSTRACT: Tensile strength (TS), elongation (E), water vapor permeabilities (WVP) and solubilities were determined for highly carboxymethylated starch (HCMS)-based edible films plasticized with sorbitol (S), xylitol (X), mannitol (M) and glycerol (G). TS and E of HCMS-based film increased as the concentration of plasticizer S, M or × increased. TS of the HCMS-based film containing combined plasticizers were higher than those of films containing single plasticizer. The WVP of HCMS-based films seemed to decreased as the concentration of M, X or G plasticizer increased. Increasing plasticizer concentrations in HCMS-based film resulted in decreasing solubility of the films. [source] Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouthJOURNAL OF ORAL REHABILITATION, Issue 10 2007J. A. SHIP summary, Polypharmacy is a common cause of salivary hypofunction, producing symptoms of dry mouth or xerostomia, especially among older populations. As the number of older people continues to increase, polypharmacy-induced salivary hypofunction is becoming an increasing problem. Many over-the-counter products are available for relieving symptoms of dry mouth, but few have been tested in controlled clinical investigations. The purpose of this investigation was to evaluate the safety and efficacy of a group of topical dry mouth products (toothpaste, mouth rinse, mouth spray and gel) containing olive oil, betaine and xylitol. Forty adults were entered into this single-blinded, open-label, cross-over clinical study and 39 completed all the visits. Subjects were randomly assigned at baseline to using the novel topical dry mouth products daily for 1 week, or to maintain their normal dry mouth routine care. After 1 week, they were crossed over to the other dry mouth regimen. The results demonstrated that the use of the novel topical dry mouth products increased significantly unstimulated whole salivary flow rates, reduced complaints of xerostomia and improved xerostomia-associated quality of life. No clinically significant adverse events were observed. These data suggest that the daily use of topical dry mouth products containing olive oil, betaine and xylitol is safe and effective in relieving symptoms of dry mouth in a population with polypharmacy-induced xerostomia. [source] Caregiver Acceptability and Preferences for Early Childhood Caries Preventive Treatments for Hispanic ChildrenJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 4 2009Sally H. Adams RN Abstract Objective: The objective of this study was to determine caregiver treatment acceptability and preferences for five preventive dental treatments for early childhood caries in young Hispanic children. Methods: We interviewed 211 parents/caregivers of Hispanic children attending Head Start programs regarding their acceptability of, and preferences for, five standard preventive dental treatments for young children. Treatments assessed were toothbrushing with fluoride toothpaste, fluoride varnish, and xylitol in food for children, and xylitol gum and chlorhexidine rinse for mothers. The interview assessment included presentation of illustrated cards with verbal description of treatment, photograph/video clip, and treatment samples. Parents rated the acceptability of each treatment (1-5 scale) and treatment preferences within each of 10 possible pairs. Individual treatment preferences were summed to create overall preference scores (range 0-4). Results: All treatments were rated as highly acceptable, however, there were differences (range 4.6-4.9; Friedman chi-square = 23.4, P < 0.001). Chlorhexidine, toothbrushing, and varnish were most acceptable, not different from each other, but more acceptable than xylitol in food (P < 0.05). Summed treatment preferences revealed greater variability (means ranged 1.4-2.6; Friedman chi-square = 128.2, P < 0.001). Fluoride varnish (2.6) and toothbrushing (2.5) were most highly preferred, and differences between preferences for xylitol in food (1.4), xylitol gum (1.5), and chlorhexidine (2.1) were all significant (P < 0.001). Preferences for chlorhexidine were also significantly greater than those for the xylitol products (P < 0.001). Conclusions: All five treatments were highly acceptable, however, when choosing among treatments overall, fluoride varnish and toothbrushing were favored over other treatments. [source] Effects of Saccharide Set Retarders on the Hydration of Ordinary Portland Cement and Pure Tricalcium SilicateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2010Linghong Zhang The effects of aliphatic sugar alcohols (e.g., threitol, xylitol, sorbitol) on the hydration of tricalcium silicate (C3S) and ordinary portland cement (OPC) were investigated and compared with those of sucrose, a well-established cement set retarder. Only sugar alcohols which contain threo diol functionality retarded the setting of C3S and OPC, their efficacy increasing with the number of threo hydroxy pairs and, to a smaller extent, with the overall population of hydroxy groups. None, however, were as effective as sucrose. The initial and final setting times increased exponentially with the concentration of saccharide, although the hydration of OPC was less inhibited than that of C3S. Saccharides function as "delayed accelerators," that is, cement hydration is first inhibited and then proceeds faster than in saccharide-free cement. This behavior is consistent with the theory that the induction period is controlled by slow formation and/or poisoning of the stable calcium silicate hydrate (CSH) nuclei. The early inhibiting influence of saccharides on CSH precipitation is apparently stronger than on the growth of crystalline calcium hydroxide. Saccharides did not negatively affect the degree of hydration and compressive strength of fully set OPC paste; on the contrary, sorbitol yielded modest increases. [source] Utilisation of corn (Zea mays) bran and corn fiber in the production of food components,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2010Devin J Rose Abstract The milling of corn for the production of food constituents results in a number of low-value co-products. Two of the major co-products produced by this operation are corn bran and corn fiber, which currently have low commercial value. This review focuses on current and prospective research surrounding the utilization of corn fiber and corn bran in the production of potentially higher-value food components. Corn bran and corn fiber contain potentially useful components that may be harvested through physical, chemical or enzymatic means for the production of food ingredients or additives, including corn fiber oil, corn fiber gum, cellulosic fiber gels, xylo-oligosaccharides and ferulic acid. Components of corn bran and corn fiber may also be converted to food chemicals such as vanillin and xylitol. Commercialization of processes for the isolation or production of food products from corn bran or corn fiber has been met with numerous technical challenges, therefore further research that improves the production of these components from corn bran or corn fiber is needed. Published 2010 by John Wiley & Sons, Ltd. [source] Ascorbic acid destruction in aqueous model systems: an additional discussionJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2001Ana M Rojas Abstract The influence of different non-electrolytes (fructose, xylitol, glucose/mannitol mixture) and electrolytes (NaCl, KCl) on anaerobic L -ascorbic acid (AA) degradation in an aqueous model system (pH 3.5, aw 0.94) was studied to assess the effect on that reaction of substances commonly used to diminish the water activity of fruit or vegetable juices, as well as its relation with non-enzymatic browning (NEB) development, at processing (70, 80, 90,°C) and storage (24, 33, 45,°C) temperatures. AA degraded as a function of time with a behaviour that could be described by first-order kinetics at all temperatures studied, and activation energies could be calculated using the Arrhenius law. The presence of humectants enhanced AA destruction, with D -fructose promoting the fastest L -ascorbic acid destruction and browning development at processing temperatures. The influence of humectants on NEB seemed to determine differences between their influence on AA degradation. Water activity decrease by humectant addition produced higher AA stability in solution at storage temperatures. The differential effect of each humectant used to decrease the water activity seemed to be related to its influence on solvent structure. © 2001 Society of Chemical Industry [source] Xylitol intoxication associated with fulminant hepatic failure in a dogJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 3 2007Jeffrey M. Todd DVM Abstract Objective: To describe a case of xylitol intoxication causing fulminant hepatic failure in a dog. Case summary: A 2.5-year-old castrated male English Springer Spaniel weighing 26 kg, was presented after ingestion of half of a loaf of bread containing the sweetener xylitol. Toxic effects of the xylitol in this dog included vomiting, mild hypoglycemia and fulminant hepatic failure. Clinical management of acute hepatic failure and subsequent coagulopathy with supportive care and fresh frozen plasma is described. The dog was discharged 3 days after admission after a full clinical recovery. New or unique information provided: This paper describes the clinical consequence and successful treatment of fulminant hepatic failure in a dog following ingestion of xylitol. [source] Effect of the reversal of coenzyme specificity by expression of mutated Pichia stipitis xylitol dehydrogenase in recombinant Saccharomyces cerevisiaeLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2007J. Hou Abstract Aims:, To determine the effects on xylitol accumulation and ethanol yield of expression of mutated Pichia stipitis xylitol dehydrogenase (XDH) with reversal of coenzyme specificity in recombinant Saccharomyces cerevisiae. Methods and Results:, The genes XYL2 (D207A/I208R/F209S) and XYL2 (S96C/S99C/Y102C/D207A/I208R/F209S) were introduced into S. cerevisiae, which already contained the P. stipitis XYL1 gene (encoding xylose reductase, XR) and the endogenously overexpressed XKS1 gene (encoding xylulokinase, XK). The specific activities of mutated XDH in both strains showed a distinct increase in NADP+ -dependent activity in both strains with mutated XDH, reaching 0·782 and 0·698 U mg,1. In xylose fermentation, the strain with XDH (D207A/I208R/F209S) had a large decrease in xylitol and glycerol yield, while the xylose consumption and ethanol yield were decreased. In the strain with XDH (S96C/S99C/Y102C/D207A/I208R/F209S), the xylose consumption and ethanol yield were also decreased, and the xylitol yield was increased, because of low XDH activity. Conclusions:, Changing XDH coenzyme specificity was a sufficient method for reducing the production of xylitol, but high activity of XDH was also required for improved ethanol formation. Significance and Impact of the Study:, The difference in coenzyme specificity was a vital parameter controlling ethanolic xylose fermentation but the XDH/XR ratio was also important. [source] Hydroxylated Linear Polyurethanes Derived from Sugar AlditolsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 6 2009Romina Marín Abstract A set of linear [m,n]-type polyurethanes was synthesized by reaction of HDI or MDI with conveniently protected sugar alditols L -threitol (LTh), L -arabinitol (LAr) and xylitol (Xy). of the resulting polyurethanes ranged between 10,000 and 60,000 with polydispersities around 2. They were thermally stable, showing no decomposition up to temperatures near 300,°C. They all were amorphous polymers with Tg highly dependent on the constitution of the diisocyanate, but scarcely dependent on the structure of the alditol. Hydrogenation of the LThBn-HDI polyurethane yielded partially debenzylated products with Tg values ranging between 20 and 30,°C. Fully benzylated polyurethanes showed high resistance to hydrolytic degradation, whereas polyurethane with free hydroxyl side groups degraded significantly in saline buffer at pH,=,10 and 37,°C. [source] Xylitol inhibition of anaerobic acid production by Streptococcus mutans at various pH levelsMOLECULAR ORAL MICROBIOLOGY, Issue 4 2003H. Miyasawa Xylitol inhibits the glycolysis and growth of Streptococcus mutans. We studied the inhibitory effect of xylitol on the acid production of S. mutans at several pH levels under the strictly anaerobic conditions found in the deep layer of dental plaque. Xylitol inhibited the rate of acid production from glucose and changed the profile of acidic end products to formate,acetate dominance, with a decrease in the intracellular level of fructose 1,6-bisphosphate and an intracellular accumulation of xylitol 5-phosphate (X5P). These results were notable at pH 5.5,7.0, but were not evident at pH 5.0. Since the activity of phosphoenolpyruvate phosphotransferase for xylitol was greater at higher pH, it is suggested that xylitol could be incorporated more efficiently at higher pH and that the resultant accumulation of X5P could inhibit the glycolysis of S. mutans more effectively. [source] | |||||||||||||||||||||||||||||||