Saccharides


Molisch s test A general test for carbohydrates. The carbohydrate is dissolved in water, alcoholic 1-naphthol added, and concentrated sulphuric acid poured down the side of the tube. A deep violet ring is formed at the junction of the liquids. A modification, the rapid furfural test , is used to distinguish between glucose and fructose. A mixture of the sugar, 1-naphthol, and concentrated hydrochloric acid is boiled. With fructose and saccharides containing fructose a violet colour is produced immediately the solution boils. With glucose the appearance of the colour is slower.  [c.264]

Cane sugar.—Melts, darkens, then chars, and finally burns, with a marked odour of burnt sugar. Typical of the changes given by mono- and di-saccharides.  [c.320]

All carbohydrates (mono-, di- and poly saccharides) give the Molisch colour test for details, see Section III,139,(i).  [c.1069]

Cane sugar.—Melts, darkens, then chars, and finally burns, with a marked odour of burnt sugar. Typical of the changes given by mono- and di-saccharides.  [c.320]

The hydroxyl groups of glucose (and, of course, other saccharides) must be regio- and stereo-selectively attacked, if this most abundant natural carbon compound is to be used as starting material. We shall first show with a few selected examples, how this can be achieved (A.H. Haines, 1976 J. Lehmann, 1976 L. Hough, 1979).  [c.266]

Amylopectin and glycogen are saccharides similar to amylose, except with branched chains.  [c.18]

SABRE process Saccharides  [c.865]

Boronic acid—diol covalent interactions creating five- or six-membered rings reversibly form in aqueous media, thus, providing an important tool in the recognition of saccharides (153—155). Moreover, many monosaccharides possess at least two binding sites (diol area) which differ from other monosaccharides. Based on this strategy a number of small saccharide selective receptor molecules with conformationaHy weU-defined distance and orientation between two boronic acid functionahties have been designed. An example is given in Figure 24d (156). D-Glucose yields a relatively strong 1 1  [c.188]

Raw Materials. The highly branched, short-chain polyols used for rigid foams can be initiated from amines such as diethylenetriamine to provide five functional sites or saccharides such as sorbitol or sucrose that have 6 or 8 functional sites, respectively. Subsequent polymerization of PO and/or EO at low levels further controls viscosity and reactivity of the resultant polyol. The level of oxide addition also contributes to the rigidity of the final foam product by controlling the molecular weight per branch point as well as influencing shrinkage resistance and moisture sensitivity. Amine-initiated polyols tend to be autocatalytic due to the tertiary amine groups residual in the molecule.  [c.418]

Production and Utilization. The nutritional requirements of X. campestris have been studied in order to optimize the production of xanthan gum. Fermentations for the industrial production of xanthan gum are done at 28°C, and utilize glucose concentrations from 1—5% (362). Higher glucose concentrations do not result in higher levels of gum biosynthesis. Saccharides such as sucrose, starch, and maltodextrins can also be used for gum production. The use of a completely defined media for gum production has been described (230). It has also been shown that some organic acids including pymvic, succinic, and a-ketoglutaric acids increase the production of xanthan gum. It is necessary to maintain a neutral pH during fermentation in order to obtain maximal yields during polymer biosynthesis the medium becomes acidic, but can be neutralized by the addition of a suitable base.  [c.302]

Various low cost sacrificial agents decrease surfactant adsorption on reservoir rock and increase the surfactant propagation rate. These agents include lignosulfonates and chemically modified lignosulfonates (4,75,151). Sodium saccharide wastes from wood pulping (244) and low molecular weight polyethylene oxide (245) have also been used. Alkaline chemicals (208,209), particularly sodium siUcate (246), which precipitate in the presence of divalent metal ions, can increase the surfactant propagation rate. Intermixing of polymer mobiUty control fluid with a previously injected surfactant slug can result in surfactant—polymer interactions affecting iaterfacial behavior and reducing oil displacement efficiency (246).  [c.194]

Medium Consistency Oxygen. The cost of dewatering, autooxidation, and combustion, especially of pulp impurities such as pitch, has led to the development of processes that operate at medium (10—12%) consistency. Although all of the oxygen needed for reaction in medium consistency oxygen bleaching systems caimot be dissolved into the Hquid phase at 12% consistency, new mixers make it possible to disperse sufficient oxygen in the pulp suspension as small bubbles. Subsequent dissolution and reaction take place as the Hquid-phase oxygen is depleted of oxygen. In medium consistency systems the pulp is thoroughly washed to minimise carryover of black Hquor soflds that compete with lignin for reaction with oxygen. In medium consistency systems (Fig. 33) the reaction is conducted in the presence of 2—3 wt % NaOH. Oxygen consumption is about 110 kg equivalent chlorine per metric ton of pulp, about 2.5% oxygen based on oven-dry pulp. Reaction conditions are typically one hour at 85—110°C to reduce the lignin content of softwood kraft pulp from 6 to ca 3 wt %. Because pulp saccharides are susceptible to oxygen degradation, magnesium salts are usually added as protectors. Catalytic metal concentration can be minimised by incorporating a preliminary acid wash or stage but this is not being practiced commercially.  [c.281]

Analysis and Specifications. Typical product analyses include sohds level, ash, color, conductivity, purity, and minor saccharide levels (19). Specifications for anhydrous and monohydrate crystalline dextrose are available (15). High quahty anhydrous dextrose produced for the pharmaceutical industry is prepared in accordance with additional specifications (20).  [c.292]

High fmctose com symps (HFS, HFCS, isosymp, isoglucose) are concentrated carbohydrate solutions containing primarily fmctose and dextrose as well as lesser quantities of higher molecular weight saccharides. A 42 wt % fmctose symp is produced by partial enzymatic isomerization of dextrose hydrolyzate.  [c.293]

Analysis, Specifications, and Health Factors. Com symps are usually sold with a specification of the Baumn measurement which is related to sohds content. A typical value is 43.5° Be, corresponding to 80.3 wt % sohds for a 42-DE acid-converted symp. Sohds content for symps at 41, 42, 43, 44, and 45° Be (sp gr 1.39, 1.41, 1.42, 1.43, and 1.45) are 75.0, 77.1, 79.1, 81.2, and 83.3 wt %, respectively. Higher DE symps exhibit slightly higher sohds levels at the same densities. DE is deterrnined by copper reducing methods. Saccharide composition is deterrnined by high performance hquid chromatography. Other analyses include color, iron, and pH. Specifications for glucose symp and dried glucose symp are available (53). Maltodextrin and com symp products are substances that are presumed to be GRAS by the EDA (54). Health and safety aspects are the same as those for dextrose.  [c.295]

Derivatization is useful for detection of compounds such as amino acids and amines that lack easily detectable groups. For similar reasons, saccharides, as a class of compound, ehcit much interest. Two derivatization schemes have been reported using benzamide (61) and FMOC—hydrazine (62) to produce fluorescent products.  [c.245]

Immunology is the basis of vaccine technology. Only through the better understanding of the function of the human immune system can better antigens as vaccine candidates be designed. Eor example, the discovery of the functions of T- and B-lymphocytes led to the development of capsular saccharide—protein conjugate vaccines. Discovery of the different Th 1 and Th 2 immune responses also generated great interest in designing a vaccine that can stimulate a specific immune response, which may be critical for some viral vaccines. CeU-mediated immunity (CMI) has also been demonstrated to be critical for a successful vaccine. Several vaccine candidates, especiaUy for viral vaccines, have been based on this approach. The mucosal and secretory immune system has also been studied extensively. This area wiU lead to the better design of vaccines for oral deUvery or intranasal deUvery of vaccine, which may be more efficacious for diseases originating in the mucosal system.  [c.360]

The generalized stmcture is a highly substituted monocyclic lactone (aglycone) to which is attached one or more saccharides glycosidically linked to hydroxyl groups on either the aglycone or another saccharide. The aglycones are derived via similar polyketide biosynthetic pathways and thus share many stmctural features in terms of pattern and stereochemistry of substituents (28). Traditional macroHde antibiotics are divided into three families according to the size of the aglycone which can be 12-, 14-, or 16-membered.  [c.93]

Table 1. Saccharides Found in Macrolide Antibiotics Table 1. Saccharides Found in Macrolide Antibiotics
Figure Bl.l 1.10 offers an example. It shows the 400 MHz H NMR spectrum of a-I-methylglucopyranose, below two fiirther spectra where H-decoupling has been applied at H-1 and H-4 respectively. The main results of the decouplings are arrowed. Irradiation at the chemical shift position of H-1 removes the smaller of the two couplmgs to H-2. This proves the saccharide to be in its a fonn, i.e. with ( ) xi 60° rather than 180°, according to the Karplus relationship given previously. Note tliat both the H-1 resonance and the overlapping solvent peak are almost totally suppressed by the saturation, caused by the decoupling irradiation. The H-4 resonance is a near-triplet, created by the two large and nearly equal couplings to H-3 and H-5. In both tliese cases, ( ) 180°. The spectrum in this shift region is complicated by the methyl singlet and by some minor peaks from impurities. However, these do not affect the decoupling process, beyond being severely distorted by it. Genuine effects of decoupling are seen at the H-3 and the H-5 resonances only. Figure Bl.l 1.10 offers an example. It shows the 400 MHz H NMR spectrum of a-I-methylglucopyranose, below two fiirther spectra where H-decoupling has been applied at H-1 and H-4 respectively. The main results of the decouplings are arrowed. Irradiation at the chemical shift position of H-1 removes the smaller of the two couplmgs to H-2. This proves the saccharide to be in its a fonn, i.e. with ( ) xi 60° rather than 180°, according to the Karplus relationship given previously. Note tliat both the H-1 resonance and the overlapping solvent peak are almost totally suppressed by the saturation, caused by the decoupling irradiation. The H-4 resonance is a near-triplet, created by the two large and nearly equal couplings to H-3 and H-5. In both tliese cases, ( ) 180°. The spectrum in this shift region is complicated by the methyl singlet and by some minor peaks from impurities. However, these do not affect the decoupling process, beyond being severely distorted by it. Genuine effects of decoupling are seen at the H-3 and the H-5 resonances only.
Mono- and di saccharides are colourless solids or sjrrupy liquids, which are freely soluble in water, practically insoluble in ether and other organic solvents, and neutral in reaction. Polysaccharides possess similar properties, but are generally insoluble in water because of their high molecular weights. Both poly- and di-saccharides are converted into monosaccharides upon hydrolysis.  [c.453]

The synthesis of complex organic molecules demands the availability of a variety of protective groups to ensure the survival of reactive functional groups during synthetic operations. An ideal protective group combines stability under a wide range of conditions with susceptibility to facile removal ( deblocking ) by a specific, mild reagent. It is also desirable that the introduction of the blocking group is easy and that its reactions are complementary to other protecting groups. Within the last 20 years a large variety of new protective groups capable of removal under exceptionally mild and/or highly specific conditions has been developed mainly in syntheses of natural oligomers, e.g. peptides (see p. 229), nucleotides (see p. 216), and saccharides (see p. 266ff.), which has been summarized in a book by J.W.F. McOmie (1973). We shall discuss only a few protecting agents of common functional groups, which have proven to be useful in synthesis, and indicate some possible sequences for working with these blocking agents.  [c.154]

The Latin word for sugar is saccharum and the derived term saccharide is the basis of a system of carbohydrate classification A monosaccharide is a simple carbohydrate one that on attempted hydrolysis is not cleaved to smaller carbohydrates Glucose (C6H12O6)  [c.1026]

A rationalization of the complex behavior of pectins in solutions and gels with respect to their stmcture, solvation, and the presence of ions and other saccharides has been presented (123). The solution and sorption properties of gum tragacanth and the pectin isolated from the roots of Hibiscus mani/)ot F (Tororoaoi) contributes to their use in specialty paper manufacture (124—126).  [c.32]

J. F. Robyt, ia J. J. Marshall, ed.. Mechanisms of Saccharide Pofmeri ation and Depoljmeri tion Academic Press, New York, 1980, pp. 43—54.  [c.306]

Saponins are widely distributed in plants and marine organisms and consist of a steroid or terpene skeleton attached to a saccharide (Fig. 4). In plants, for example, many sapogenins contain sugar residues attached to the 3P-hydroxyl group. Classical methods of isolation of saponins were inadequate for separating individual components therefore, the characterization of most of the pure saponins arose only in the late 1970s with the integration of siUca gel column chromatography, semipreparative hplc, preparative dc, and special isolation techniques adapted to particular situations.  [c.419]

Fmctose possesses coUigative properties that distinguish it from sucrose, glucose, and other nutritive sweeteners. It is one of the more effective monosaccharide humectants, binding moisture and lowering water activity, in food appHcations, thereby rendering the food products less susceptible to microbial growth and more stable to moisture loss (3,4). Ratios of fmctose and higher molecular weight saccharides, oligosaccharides, and polysaccharides can be balanced to give increased control over freezing temperatures and storage stabiHty in fro2en products.  [c.44]

Maltose [69-79-4] (malt sugar) is a disacchatide, 4-0-a-D-glucopyranosyl-D-glucose (3), comprising two molecules of glucose (dextrose). Although occurring in some plants and fmits (26,27), it is more frequently recognized as a stmctural component of starch. Pure maltose is isolated with difficulty from a directed starch hydrolysate, ie, high maltose com symp, by precipitation with ethanol. Purification can be achieved by way of the -maltose octaacetate. Removal of the acetate groups allows crystallization of the monohydrate of -maltose. Commercial maltose typically contains 5—6 wt % of the trisacchatide maltotriose with traces of glucose (28). High maltose symps from starch typically contain ca 8—9 wt % glucose, 40—80 wt % maltose, with higher saccharides as the remainder (29,30).  [c.45]

As of this writing (ca 1996), an ideal alternative sweetener does not exist. There are, however, many sweet compounds ia use, which generate less calories than sugar, albeit without all the advantages of sugar. These alternative sweeteners can be classified iato two groups nutritive and nonnutritive. Alternative nutritive sweeteners are less caloric than sugar, but retain many of sugar s desirable chemical and physical properties. Hence these are useful as hulking agents ia sugar-free products. Principal examples of alternative nutritive sweeteners are the sugar alcohols (qv), eg, sorbitol [50-70-4], mannitol [69-65-8], xyhtol [87-99-0], maltitol [585-88-6], lactitol [585-86-4], erythritol [149-32-6], hydrogenated starch hydrolysate and isomalt, a mixture of glucosyl sorbitol [534-73-6] and glucosyhnannitol [20942-99-8]. These alcohols are reduced saccharides resulting from catalytic hydrogenation and, for the most part, are less sweet and less caloric than sugar (ca 2.4 kcal/g (10.0 kJ/g)) (1) and mostly noncariogenic. Erythritol reportedly yields only 0.4 kcal/g (1.67 kJ/g). Sorbitol, mannitol, and xyUtol are approved food additives ia the United States.  [c.272]

NHDC is an off-white powder having low solubiUty in water (0.5 g/L at room temperature). It is quite stable over a broad range of pH and temperature. Under extreme conditions, hydrolysis of the ether linkage between the saccharides and the aglycone can take place. However, the aglycone itself is reported to be sweet. NHDC is allowed for use as a sweetener by the European Union Sweeteners Directive in 1994. It has not been approved as a sweetener in the United States. In 1993, however, it was affirmed by FEMA as a GRAS flavor modifier (EEMA no. 3811) for many food categories.  [c.281]

Com sweeteners, maple symp, and molasses, all commercially available symps, are concentrated solutions of carbohydrate. These products, produced for a variety of food and nonfood appHcations, are in some cases also available in a dry form. Com sweeteners are prepared from hydroly2ed starch (qv) and include dextrose [50-99-7] (D-glucose), high fmctose com symp (HFS), regular com symp, and maltodextrin (see Sweeteners), which all have in common the raw material source, general methods of preparation, and many properties and appHcations. Dextrose, the common or commercial name for D-glucose, is available as a symp or as a pure crystalline soHd. HFS is produced by the partial enzymatic isomerisation of dextrose. Com symps and maltodextrins are clear, colorless, viscous Hquids prepared by hydrolysis of starch to solutions of dextrose, maltose, and higher molecular weight saccharides. Maple symp, like com symp, is a nutritive sweetener produced as a concentrated carbohydrate (sucrose) solution. Molasses is a symp produced as a by-product of sugar (qv) manufacture.  [c.288]

Com symps [8029-43 ] (glucose symp, starch symp) are concentrated solutions of partially hydrolyzed starch containing dextrose, maltose, and higher molecular weight saccharides. In the United States, com symps are produced from com starch by acid and enzyme processes. Other starch sources such as wheat, rice, potato, and tapioca are used elsewhere depending on avadabiHty. Symps are generally sold in the form of viscous Hquid products and vary in physical properties, eg, viscosity, humectancy, hygroscopicity, sweetness, and fermentabiHty.  [c.294]

Properties. Com symps are defined as those starch hydrolysis products exhibiting a DE of 20—99.4. Lower DE products are classified as maltodextrins [9050-36-6] and higher DE products as dextrose. Symps are often described in terms based on the type of production process, ie, acid conversion, acid—enzyme conversion, and enzyme—enzyme conversion on the degree of hydrolysis (high conversion) or on a particular saccharide in the symp (high maltose). Examples of some of these symps are shown in Table 5. The most adequate characterization is with respect to the concentration of individual saccharides. In many cases, it is the individual saccharides or groups of saccharides that determine symp characteristics. Consequently, corn symps exhibit many functional properties, including fermentabiHty, viscosity, humectancy—hygroscopicity, sweetness, coUigative properties, and browning reactions, which differ from the properties of other symps.  [c.294]

Standardization and Testing". RequHemeats are geaerally specified within Hceases Hi the United States, and include a variety of Hi-process tests to assess purity, safety, and potency of the iadividual components and potency and safety of the final product. Potency is standardized by determining the size of the conjugate and the quantitative amount of saccharide that is bound to the carrier protein. General safety and immunogenicity is assessed Hi animals.  [c.357]

Because one or more aminosugars are usually present, these compounds are basic and can form acid addition salts. In addition, one or more neutral sugars are often present. A few macroHdes possess no aminosugar. The saccharides share some common features they tend to be highly deoxygenated and A/- and/or 0-methylated and the amino groups are located at either positions 3 or 4. The most common sugars found in macroHdes are given in Table 1.  [c.93]


See pages that mention the term Saccharides : [c.80]    [c.1458]    [c.1461]    [c.404]    [c.404]    [c.1027]    [c.424]    [c.825]    [c.189]    [c.352]    [c.360]    [c.300]    [c.317]    [c.291]    [c.357]    [c.78]   
Purification of laboratory chemicals (2003) -- [ c.566 ]