The Measurement of Dextran in Raw Sugars Using 1H NMR1

Abstract

In the cane sugar industry the purchase price of raw cane sugar, the product of sugar cane processing, is determined by polarimetric measurement of sucrose content in raw sugar solutions, expressed as Pol. Raw sugar generally contains more than 96% sucrose, but also contains other saccharides and non-sugars which can contribute to Pol. Dextrans, one class of polysaccharides often found in raw sugar, effect an increase in Pol and interfere with subsequent refining. The U.S. sugar refining industry can impose a penalty on the raw sugar purchase price for high dextran content. While there are several wet chemical methods for the determination of dextran in raw sugar, the results of these analyses are rarely in agreement. The existing wet chemical methods for the determination of dextran in raw cane sugar are reviewed and the results of these wet chemical analyses are compared with the results obtained from the physical measurement of dextran in raw sugar by ¹H NMR spectroscopy.     

Environmentally Benign Synthesis of Sugar Orthoesters Promoted by Anhydrous Sodium Acetate and Ultrasound

A convenient and alternative procedure for the synthesis of sugar orthoesters from glycosyl bromides with anhydrous sodium acetate as base under ultrasound irradiation is described. Various sugar and sugar‐sugar orthoesters were prepared in 70%–91% isolated yields.     

Production of fuel alcohol from wheat by VHG technology

Very high gravity (VHG) wheat mashes containing more than 300 g of dissolved solids per liter were prepared and fermented with active dry yeast at 20, 25, 30, and 35°C with and without yeast extract as nutrient supplement. At 20°C, mashes with 38% (w/v) dissolved solids end-fermented without any nutrient supplementation and maximum ethanol yields of 23.8% (v/v) were obtained. With increasing temperatures, the sugar consumption decreased. Addition of yeast extract stimulated the rate of fermentation at all temperatures, but did not increase the total amount of sugar consumed. The stimulatory effect of yeast extract on cell multiplication decreased with increasing sugar concentration, and virtually no difference in cell number was observed between yeast extract-supplemented and unsupplemented mashes at sugar concentrations above 33% (w/v). The fermentative capacity of the yeast (expressed as maximum specific rate of sugar consumption) remained the same at all sugar concentrations in unsupplemented mashes, but decreased in yeast extract-supplemented mashes at sugar concentrations below 33% (w/v). When the sugar concentration was above 33% sugar (w/v), the fermentative capacity in yeast extract-supplemented mashes was greater than that observed in unsupplemented samples.     

Simple and rapid method for evaluating stickiness of cotton using thermogravimetric analysis

Thermogravimetric analysis (TGA) with nitrogen and oxygen as carrier gas is used for the analysis of cotton lint samples for evaluating their stickiness. The advantage of the low melting point of trehalulose, a commonly found sugar, in the presence of oxygen as carrier gas is used for the evaluation. The oxidation of sugar present in the cotton lint results in increased weight around the melting point, which is proportional to the sugar content. The decomposition of the sugar further results in weight loss. This method is compared with the sticky cotton thermodetector and viscosity method for the estimation of sugar content. Good agreement between the methods suggests the usefulness and simplicity of TGA for estimation of stickiness in cotton.     

离子交换纤维对亚硫酸法糖汁脱色性能研究

研究了强碱性阴离子交换纤维对亚硫酸法清净糖汁的脱色性能.对沉清工段清汁的脱色效果和影响因素进行了研究.结果表明,阴离子交换纤维对沉清汁的脱色效果明显,脱色后清汁色值低于30 oSt.再生液洗脱再生反复使用90次后,脱色效果达84%.与717强碱性苯乙烯系阴离子交换树脂相比具有脱色容量高、脱色速度快、再生速度快和抗污染能力强等优点.通过离子交换纤维的脱色处理,亚硫酸法清净糖汁可以达到制备优质糖的要求.     

Recent Progress in Enzymatic Synthesis of Sugar Nucleotides

Glycosylation is one of the most important reactions in nature as it results in the formation of glycoconjugates with diverse biological functions. Sugar nucleotides serve as the natural donor molecules for the biosynthesis of such glycoconjugates and other carbohydrates. Furthermore, these donor molecules are also indispensable building blocks for the enzymatic synthesis of carbohydrates in vitro using Leloir-type glycosyltransferases. Given such importance, the biosynthetic pathways of sugar nucleotides have been exploited, enabling the development of both chemical and enzymatic approaches to produce these molecules. A survey of recent progress in enzymatic synthesis of common mammalian sugar nucleotides as well as their derivatives is thus presented. As a popular strategy, conjugation of sugar nucleotide synthesis with glycosyltransfer reactions and in vivo production of sugar nucleotides are also included.     

INAA and AAS of different products from sugar cane industry in Pakistan: Toxic trace elements for nutritional safety

Instrumental neutron activation analysis (INAA) have been used to determine As, Br, Hg, Sb and Se in combination with atomic absorption spectrometry (AAS) as a complementary technique for the quantification of Cd and Pb in jaggery, brown sugar, white sugar and molasses. All sugar cane products were collected from the local sugar cane industry of Pakistan. The highest concentration of these potentially toxic elements was quantified in molasses; however, molasses together with jaggery, brown sugar and white sugar contains trace amounts of all of these elements. Due to very low concentration of Cd it could only be detected in molasses. To evaluate the percentage contribution of these elements in the sugar cane products to the weekly recommended values, intakes on weekly consumption of 100 g of each item have also been calculated which follow the pattern Br>Se>Pb>Hg>As>Sb. The elevated Br contents may be attributed to the use of Br-containing chemicals for fumigation; however, these contents are well within the tolerance levels. The estimated weekly intake of all toxic elements is very low indicating that sugar cane products can be safely ingested as part of the diets.     

Highly redispersible sugar beet nanofibers as reinforcement in bionanocomposites

A simple method for preparing redispersible nanofibers from sugar beet residue and their use as a well-dispersed reinforcement for a polyvinyl alcohol (PVA) matrix is reported. It is known that the redispersion of dried cellulose nanofibers is difficult because of the formation of strong hydrogen bonds between the nanofibers. The results show that the properties of the initial sugar beet nanofiber suspension can be recovered without the use of chemical modification or additives with higher pectin and hemicellulose content. Undried and redispersed nanofibers with and without pectin were used as nanocomposite reinforcement with PVA. The redispersed nanofibers were as good reinforcements as the undried nanofibers. The tensile strength and elastic modulus of the nanocomposites with the redispersed sugar beet nanofibers were as good as those of the nanocomposites with undried nanofibers. Interestingly, the nanofiber dispersion in the PVA matrix was better when sugar beet nanofibers containing pectin and hemicellulose were used as reinforcements.     

Determination of sugar alcohols in confectioneries by high-performance liquid chromatography after nitrobenzoylation

A method was developed for the determination of sugar alcohols, meso-erythritol, xylitol, D-glucitol, D-mannitol, maltitol and parachinit by high-performance liquid chromatography (HPLC). The sugar alcohols were converted into strong ultraviolet (UV)-absorbing derivatives with p-nitrobenzoyl chloride. HPLC was performed on a phenyl column, using acetonitrile-water (67:33) as mobile phase and UV detection (260 nm). The calibration curves for all sugar alcohols tested were linear in the 10-250 microg/ml range. The average recoveries of the sugar alcohols from four sugarless confectioneries spiked at 5 and 10% levels of six sugar alcohol standards ranged from 73.2 to 109.0% with relative standard deviations ranging from 0.7 to 9.0%. The detection limit of the developed method was 0.1% for the above sugar alcohols contained in the samples.     

含糖聚合物的酶促合成

介绍含糖聚合物的酶促催化合成研究进展，主要包括主链含糖聚糖酯，支链含糖聚合物，中心为糖的星形取合物，硅烷主链含糖聚合物等。主链含糖聚合物直接由酶促催化酯化或酯交换作用制得；支链含糖聚合物由酶促合成糖酯单体及单体的化学聚合两步制得。     

Recent advances in catalytic production of sugar alcohols and their applications

Conversion of non-edible biomass into fuels and value-added chemicals has achieved great attention to cope the world's energy requirements. Lignocellulose based sugar alcohols such as sorbitol, mannitol, xylitol, and erythritol can be potentially used as emerging fuels and chemicals. These sugar alcohols can be converted into widely used products(e.g. polymer synthesis, food and pharmaceuticals industry). The heterogeneous catalytic production of sugar alcohols from renewable biomass provides a safe and sustainable approach. Hydrolysis, coupled with hydrogenation and hydrogenolysis has been proved to be more effective strategy for sugar alcohols production from biomass. This review summarizes the recent advances in biomass upgrading reactions for the production of sugar alcohols and their comprehensive applications.     

Instrumental neutron activation analysis of different products from the sugarcane industry in Pakistan--part 1: essential elements for nutritional adequacy

Jaggery, brown sugar, white sugar, and molasses collected from the local sugarcane industry of Pakistan have been analyzed for essential elements in order to estimate their nutritional adequacy. Instrumental neutron activation analysis was used to determine Ca, CI, Co, Cr, Fe, K, Mg, Mn, Na, and Zn through sequential, short, medium, and long irradiation times. Maximum concentrations for most of these elements were determined in molasses, with lower concentrations determined in jaggery and brown sugar; white sugar contained trace amounts of all essential elements. Contributions to the weekly Recommended Dietary Allowance (RDA) values for the elements were estimated only for jaggery, brown sugar, and white sugar because molasses in Pakistan is not consumed as a dietary item. Jaggery contributes the highest percentages of Cr, Mg, Mn, and Zn, whereas the highest percentages of Cl, Fe, K, and Na can be acquired from brown sugar. The contribution of white sugar to the weekly RDAs for these elements is negligible, indicating that white sugar is a poor source of the essential elements. However, the introduction of molasses to the diet can contribute to an adequate intake of these elements.     

Applications of ion chromatography in cane sugar research and process problems

Ion chromatography (IC) offers the sugar technologist a simple, reliable technique for the simultaneous separation and determination of inorganic and organic ions in complex process mixtures. Identification and measurement of ions present in sugar liquors are important factors in understanding and maximising sugar recovery. Choice of IC column packing, eluent composition and pH, and detection mode (suppressed and non-suppressed) are shown to be useful variables when analysing sugar factory products, especially the multivalent ions such as phosphate and organic acids (aconitic and oxalic acid). The IC methods show good agreement with conventional analysis methods (potentiometric titration, atomic emission and absorption). IC also produced excellent repeatability and recovery from these matrices. Examples of the application of IC analysis in applied sugar research and processing problems include clarification studies, degradation of molasses, sugar solution colour removal and factory process problems.     

Improvement of Ethanol Production Using <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> by Enhancement of Biomass and Nutrient Supplementation

Optimization of ethanol production through addition of substratum and protein-lipid additives was studied. Oilseed meal extract was used as protein lipid supplement, while rice husk was used as substratum. The effect of oil seed meal extract and rice husk was observed at varying concentration of medium sugar from 8% to 20%. Of the three oil seed meal extracts used, viz. groundnut, safflower, and sunflower, safflower was found to be most efficient. The use of oilseed meal extract at 4% was found to enhance ethanol production by almost 50% and enhanced sugar tolerance from 8% to 16%. A further increase of almost 48% ethanol was observed on addition of 2 g of rice husk per 100 ml of medium. An increase in cell mass with better sugar attenuation was observed. Further optimization was sought through use of sugarcane juice as the sugar source. While 8.9% ethanol yield with 75% sugar attenuation was observed at 20% sucrose concentration, it was found to increase to 12% (v/v) with almost complete utilization of medium sugar when sugarcane juice was used. Cell weight was also observed to increase by 26%.     

New polycationic polynorbornene latexes bearing an amphiphilic sugar corona of counterions: synthesis and complexation with DNA

A new family of polycationic polynorbornene with ω-gluconamidoalkanoates and ω-lactobionamidoalkanoates as amphiphilic counterions has been prepared. These polymers spontaneously form stable latexes in water with an amphiphilic sugar corona around the particles. With these counterions, the sugar moieties are separated from the surface of latex particles by the aminoalkanoic acid residue and consequently are remote from the surface of such latexes. Such location of sugar may promote their stronger interaction with cell receptors. These original amphiphilic compartmentalized surface polycationic latexes are able to bind and efficiently complex DNA in very small complexes. Furthermore, because of the effect of the sugar corona on the formation of the complexes, there is only a slight influence of the hydrophobicity of the counterions on DNA packing.     

玉米支链淀粉在单糖、寡糖水溶液中的粘度行为

通过乌氏粘度计和数字流变仪研究了玉米支链淀粉在单糖和寡糖溶液中的特性粘度和表观粘度.发现在稀溶液中,玉米支链淀粉的特性粘度随糖浓度的增加而降低;浓溶液中,玉米支链淀粉的糖溶液的表观粘度随糖浓度的增加而升高.小分子糖对支链淀粉在糖溶液中的特性粘度和表观粘度的影响由强到弱依次为蔗糖>麦芽糖>葡萄糖>半乳糖>果糖.     

Antimicrobial Activity of Broth Fermented with Kefir Grains

Kefir grains originate from the Caucasus region and are used for preparing beverages using sugar solution, milk, and fruit juice. As long as they are formed by a microbial consortium useful in the intestine, the produced drinks can be called probiotics. The aim of this study was to determine the antimicrobial activity during kefir fermentation in sugar broth. Fermentations with three kinds of carbohydrates (molasses, demerara sugar, and brown sugar) as carbon source were carried out. Brown sugar promoted the greatest antimicrobial activities, producing inhibition halos corresponding to 35, 14, 12, 14, and 14 mm for Candida albicans, Salmonella typhi, Shigella sonnei, Staphylococcus aureus, and Escherichia coli, respectively. Different carbon source concentrations and the time of fermentation influenced the size of the inhibition halos of the pathogenic microorganisms.     

Detection of added beet or cane sugar in maple syrup by the site-specific deuterium nuclear magnetic resonance (SNIF-NMR) method: collaborative study

Results of a collaborative study are reported for the detection of added beet or cane sugar in maple syrup by the site-specific natural isotope fractionation-nuclear magnetic resonance (SNIF-NMR) method. The method is based on the fact that the deuterium content at specific positions of the sugar molecules is different in maple syrup from that in beet or cane sugar. The syrup is diluted with pure water and fermented; the alcohol is distilled with a quantitative yield and analyzed with a high-field NMR spectrometer fitted with a deuterium probe and fluorine lock. The proportion of ethanol molecules monodeuterated at the methyl site is recorded. This parameter (D/H)I is decreased when beet sugar is added and increased when cane sugar is added to the maple syrup. The precision of the method for measuring (D/H)I was found to be in good agreement with the values already published for the application of this method to fruit juice concentrates (AOAC Official Method 995.17). An excellent correlation was found between the percentage of added beet sugar and the (D/H)I isotopic ratio measured in this collaborative study. Consequently, all samples in which exogenous sugars were added were found to have a (D/H)I isotopic ratio significantly different from the normal value for an authentic maple syrup. By extension of what is known about plants having the C4 cycle, the method can be applied to corn sweeteners as well as to cane sugar. One limitation of the method is its reduced sensitivity when applied to specific blends of beet and cane sugars or corn sweeteners. In such case, the C13 ratio measurement (see AOAC Official Method 984.23, Corn Syrup and Cane Sugar in Maple Syrup) may be used in conjunction.     

Two-dimensional HPLC coupled to ICP-MS and electrospray ionisation (ESI)-MS/MS for investigating the bioavailability in vitro of arsenic species from edible seaweed

Edible seaweed consumption is a route of exposure to arsenic. However, little attention has been paid to estimate the bioaccessibility and/or bioavailability of arsenosugars in edible seaweed and their possible degradation products during gastrointestinal digestion. This work presents first use of combined inductively coupled plasma mass spectroscopy (ICP-MS) with electrospray ionization tandem mass spectrometry (ESI-MS/MS) with two-dimensional HPLC (size exclusion followed by anion exchange) to compare the qualitative and quantitative arsenosugars speciation of different edible seaweed with that of their bioavailable fraction as obtained using an in vitro gastrointestinal digestion procedure. Optimal extraction conditions for As species from four seaweed namely kombu, wakame, nori and sea lettuce were selected as a compromise between As extraction efficiency and preservation of compound identity. For most investigated samples, the use of ammonium acetate buffer as extractant and 1 h sonication in a water bath followed by HPLC-ICP-MS resulted in 40–61% of the total As to be found in the buffered aqueous extract, of which 86–110% was present as arsenosugars (glycerol sugar, phosphate sugar and sulfonate sugar for wakame and kombu and glycerol sugar and phosphate sugar for nori). The exception was sea lettuce, for which the arsenosugar fraction (glycerol sugar, phosphate sugar) only comprised 44% of the total extracted As. Interestingly, the ratio of arsenobetaine and dimethylarsinic acid to arsenosugars in sea lettuce extracts seemed higher than that for the rest of investigated samples. After in vitro gastrointestinal digestion, approximately 11–16% of the total As in the solid sample was found in the dialyzates with arsenosugars comprising 93–120% and 41% of the dialyzable As fraction for kombu, wakame, nori and sea lettuce, respectively. Moreover, the relative As species distribution in seaweed-buffered extracts and dialyzates was found to be very similar. Collection of specific fractions from the size-exclusion column to be analysed using anion-exchange HPLC-ESI-MS/MS enabled improved chromatographic selectivity, particularly for the less retained arsenosugar (glycerol sugar), facilitating confirmation of the presence of arsenosugars in seaweed extracts and dialyzates. Using this approach, the presence of arsenobetaine in sea lettuce samples was also confirmed.     

Iterative synthesis of spacered glycodendrons as oligomannoside mimetics and evaluation of their antiadhesive properties

Dendrimer chemistry is an attractive concept for mimicry of the highly branched character of the bioactive carbohydrates found as part of a cell's sugar coat, called the glycocalyx. Glycodendrimers have thus been used to study biological processes occurring on cell surfaces, such as bacterial adhesion. This paper details a new approach in glycodendrimer synthesis, in which a 3,6-diallylated carbohydrate is utilised as core molecule, hydroboration-oxidation is the activating step, and glycosylation with branched and unbranched sugar trichloroacetimidates is used for dendritic growth. To obtain pure dendritic pseudo-tri- and -heptasaccharides in good yields, radical addition of mercaptoethanol to peripheral double bonds was also evaluated with great success. A collection of six new hyperbranched glycodendrons was tested for their potential as inhibitors of type 1 fimbriae-mediated bacterial adhesion in an ELISA and the results were interpreted with regard to sugar valency and spacer characteristics.