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At least 19 recordsLinked to original sources
PubMed1991

Investigation of the fine structure of alpha-dextrins derived from amylopectin and their relation to the structure of waxy-maize starch.

Alpha-dextrins, obtained by fractional precipitation with methanol of the products of the action of Bacillus subtilis alpha-amylase on waxy-maize amylopectin, were debranched with isoamylase and the distributions of the unit chains were analysed by gel-permeation chromatography. The large alpha-dextrins still contained long B-chains after hydrolysis for 60 min, but these were absent from the small dextrins with chain numbers of approximately 11 or less. The small dextrins contained increased amounts of chains with lengths intermediate of those of the long B-chains and the main part of the short chains. After hydrolysis for 210 min, almost all of the long B-chains had disappeared and the chains with intermediate lengths had been shortened further. The distributions of the unit chains of the internal chains, obtained by debranching of the phosphorolysis (phi)-limit dextrins, gave similar results and showed that the ratio of A- to B-chains was unchanged during the alpha-amylolysis. Models for the fine structure of the intermediate alpha-dextrins are proposed.

Amylopectin↗
PubMed1992

Estimation of the niacin requirements for tilapia fed diets containing glucose or dextrin.

Two 12-wk experiments were conducted to determine the adequate dietary niacin levels for juvenile hybrid tilapia, Oreochromis niloticus x O. aureus, when diets containing either 38% D(+)-glucose or 38% dextrin (type III, from corn) as the carbohydrate source were fed. In Experiment 1, we used 0, 40, 80, 120, 160 and 200 mg/kg of supplemental niacin in both the glucose- and dextrin-containing diets. In Experiment 2, 0, 10, 25, 40 and 55 mg/kg or 0, 10, 25, 40, 80, 120 and 160 mg/kg of supplemental niacin was incorporated in diets containing glucose or dextrin, respectively. In both experiments, fish fed niacin-deficient diets grew poorly. They developed skin, fin and mouth lesions and hemorrhages; the snout was deformed and there was gill edema. These pathologies began 6 wk after the experiments started. Plasma glucose concentrations were higher in fish fed glucose diets than those fed dextrin diets. Weight gain analyzed by broken-line regression indicated that the adequate dietary niacin level for maximal growth in rapidly growing tilapia fingerlings is 26 mg/kg in fish fed the glucose diet and 121 mg/kg in fish fed the dextrin diet.

Animal Feed↗
PubMed1991

Small intestinal starch digestion in steers: effect of various levels of abomasal glucose, corn starch and corn dextrin infusion on small intestinal disappearance and net glucose absorption.

Eight Holstein steers (four at 300 kg, four at 406 kg) fitted with an elevated carotid artery, hepatic portal and mesenteric venous catheters, and abomasal and ileal cannulas were used in several 4 x 4 Latin square experiments to evaluate small intestinal starch digestion. They were fed alfalfa hay at 1.5% of BW and abomasally infused with water or glucose, corn starch or corn dextrin (one carbohydrate per Latin square) at 20, 40 or 60 g/h, with subsequent determination of small intestinal disappearance and net portal glucose absorption. Increasing the amount of all three carbohydrates infused abomasally increased the amount of carbohydrate disappearing in the small intestine. Increased infusion of glucose caused a continual increase (linear, P less than .01) in net glucose absorption, whereas net glucose absorption for starch and dextrin was maximal at the 20 g/h infusion (quadratic, P less than .05). With the 60 g/h infusion, 94% of the glucose but only 38% of starch and 29% of small intestinal dextrin disappearance could be accounted for as net glucose absorption, leaving a large portion of starch and dextrin disappearance unaccounted for. Of the infused starch and dextrin passing the ileum, 5.8 and 7.3%, respectively, was unpolymerized glucose, indicating that, at least in the distal small intestine, complete starch hydrolysis exceeded the capacity for glucose disappearance. It is concluded that only about 35% of the raw corn starch disappearing in the steer's small intestine resulted in net portal glucose absorption.

Animals↗
PubMed1977

Intravenous infusion of a dextrin, Caloreen, in human subjects: metabolic studies.

1. Caloreen, a glucose-polymer dextrin infused into human volunteers, although producing a clear increase in total plasma carbohydrate did not produce a satisfactory increase in plasma glucose levels or serum insulin levels. 2. Urinary losses were high and although small fragments of the dextrin (suggesting metabolic breakdown of the dextrin) were demonstrated in the urine, no suppression of plasma free fatty acid, glucagon or immediate increase in the respiratory quotient were noted, suggesting that the metabolism is too slow to make it useful for parenteral nutrition in its present form. 3. A dextrin with fewer branch-links might be more suitable.

Adult↗
PubMed1975

Structures of multi-branched dextrins produced by saccharifyiing alpha-amylase from starch.

From the digest of beta-limit dextrin (prepared from glutinous rice starch) with saccharifying alpha-amylase of Bacillus subtilis [EC 3.2.1.1] (BSA), two extensibely branched dextrins consisting of nine (No. 6, Fig. 1) and ten (No 7, Fig.1) glucose units were isolated by paper chromatography. Structural analysis using various enzymes revealed that No. 6 and No. 7 were both mixtures of four triply branched dextrins. They had structures which were built up with 63-alpha-glucosylmaltotriose and/or 62-alpha-glucosylmaltose as a linking unit. However, the branching configuration and the minimum alpha-1, 4-glucosidic linkages existing between two branches followed one of the three structures shown below: (see article).

Amylases↗
PubMed1975

Elimination of precipitates in oil red O fat stain by adding dextrin.

Addition of dextrin in the final 60% isopropanol of the Lillie-Ashburn super-saturated oil red O isopropanol technic moderately intensified the stain and decreased our required staining interval. Precipitates were decreased and the diluted solution remained usable into the second week. A saturated 60% isopropanol oil red O solution contained 33 mg/100 ml. Without dextrin the fresh supersaturated solution contains 40 mg, after 3 days 25 mg. With dextrin the fresh solution contained 130 mg dye, the 10-day-old one 100 mg/100 ml.

1-Propanol↗
PubMed1992

Evaluation of malto-dextrin/glycine oral rehydration solution.

The efficacy and safety of malto-dextrin/glycine-based oral rehydration solution (ORS) when compared with the glucose-based oral rehydration solution (WHO) was evaluated in a randomized double-blind clinical trial. Thirty-one subjects and 31 controls were studied. The mean values of the ORS intake, stool output, duration of diarrhoea, urine output, weight gain and serum electrolytes were comparable in both the study and the control groups (p > 0.05). It was found that the malto-dextrin/glycine ORS offered no therapeutic advantage over the standard glucose ORS (WHO). In view of the accidental preponderance of children of significantly lower nutritional status among the control group (p < 0.05), it is likely that the efficacy of malto-dextrin/glycine ORS might actually be less than that of the glucose ORS.

Diarrhea, Infantile↗
PubMed1992

Amphiphilic properties of polysaccharides: dextrin chains as example.

Polysaccharide chains are usually considered to be highly hydrophilic, since they contain no obvious apolar moieties. However, it is possible for even these chains to display hydrophobic character, arising out of stereochemical constraints in the chain. We had earlier shown that linear dextrin chains display amphiphilic properties, since all the hydroxyl groups are disposed on one side or face of the chain and the hydrogens disposed on the other. We provide further evidence here for this conclusion that dextrins are amphiphilic chains. In contrast, dextrans and cellulosic chains do not display amphiphilicity. Oligosaccharides that can adopt incipient helical structures might display amphiphilicity. This property might be relevant to intermolecular recognition on cell surfaces, lectin-sugar binding, antigen-antibody interactions and the like, and might be manifested more in a heteromolecular recognition process than as homomolecular self-aggregation.

Buffers↗
PubMed1990

Specific assay of alpha-dextrin 6-glucanohydrolase using labeled pullulan.

A new method was developed for the assay of alpha-dextrin 6-glucanohydrolase (EC 3.2.1.41), which hydrolyzes the alpha-D (1----6) glucosidic bonds occurring in polyglucans such as pullulan and amylopectin limit dextrins. After enzymatic hydrolysis of a pullulan-dye conjugate, the remaining substrate is precipitated by adding ethanol. Colored reaction products are determined by measuring the supernatant absorbance at 534 nm. The assay is simple, specific, and suitable for both plant and bacterial enzymes.

Bacterial Proteins↗
PubMed1989

Structural and immunochemical analysis of three alpha-limit dextrin oligosaccharides.

Complete structures are described for three urinary oligodextrins from one patient with type II and one patient with type III glycogen storage disease. GLC-MS, direct probe MS, and 1H NMR demonstrate two heptasaccharides and one hexasaccharide containing only alpha 1-4 and alpha 1-6 linkages. The observation that all three oligosaccharides were present in urine of both patients and the occurrence of alpha 1-4 and alpha 1-6 linkages in characteristic sequences indicates that the oligodextrins are limit dextrins derived from alpha-amylolytic degradation of glycogen. The binding affinities of the oligodextrins for a monoclonal antibody (401/6) raised against Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc, were determined by frontal analysis. The highest affinity was exhibited by Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc followed by the two heptasaccharides and the hexasaccharide. The results from quantitative affinity measurements agree with results of structural analysis by physical methods in that all oligodextrins containing the nonreducing terminal sequence, Glc alpha 1-6Glc alpha 1-4Glc . . . , are specifically bound by the antibody with similar affinities, but the affinity is somewhat higher for chains containing the tetrasaccharide sequence Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc at the nonreducing terminal. Utilization of affinity methods offers clear advantages for isolation and characterization of oligosaccharides with very similar structures.

Antibodies, Monoclonal↗
PubMed1992

[The effects of indigestible dextrin on sugar tolerance: I. Studies on digestion-absorption and sugar tolerance].

It is widely acknowledged that high viscosity water-soluble dietary fibers such as pectin and guar gum affect a lowering of blood glucose levels and a reducing of insulin secretion following a sugar load. However, as dietary fibers vary in origin and in chemical properties, their physiological functions differ as well. In this study the effects of Indigestible Dextrin (PF-C), a low viscosity, water-soluble dietary fiber obtained through acid and heat-treatment of potato starch, on various aspects of sugar tolerance were examined. First, the influence of PF-C on sucrose hydrolysis was examined in rat intestinal mucosa cell homogenate confirming that PF-C did not inhibit sucrase activity. Then, in order to investigate the influence of PF-C on sugar digestion-absorption, an experiment was performed by using the everted intestinal sac of the rat in vitro. PF-C did not have an effect on glucose-transport into the serosal medium, whereas PF-C did inhibit the transport of hydrolyzed-glucose from sucrose, with no change in the hydrolysis of sucrose. Recently, Crane et al. reported that there is a specific route for hydrolyzed glucose from sucrose in glucose-absorption on the enteric surface (disaccharidase related transport system). The possibility exists that PF-C specifically affects this pathway. Further, total glucagon released into the serosal medium stimulated by both glucose and sucrose were reduced by PF-C. On the basis of these results, an oral sugar tolerance test was conducted in both rats and healthy human subjects. In male Sprague-Dawley rats (8 weeks old, 250-280g) concurrent administration of PF-C (0.6g/kg body weight) reduced an increase in plasma insulin levels with no change in glucose levels following a glucose (1.5g/kg body weight) load. Further noted were reductions in increases in both plasma glucose and insulin levels following a sucrose (1.5g/kg body weight) plus PF-C (0.6g/kg body weight) load to that of the sucrose (1.5g/kg body weight) single load. These findings reflect the above mentioned in vitro results. Moreover, in healthy male subjects the increase in both plasma insulin and glucagon-like immunoreactivity (Gut GLI) levels following a Trelan-G75 load were significantly reduced by concurrent administration of PF-C. From these observations it would appear that the effectiveness of reducing insulin secretion by PF-C results due to the decrease in sugar absorption by inhibiting the disaccharidase-related transport system.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Effects of dl-fenfluramine on dextrin and casein intakes influenced by textural preferences.

The effects of dl-fenfluramine (2.5 mg/kg) on selection between the textures of nutrient preparations were tested by presenting rats with a choice between pairs of three sizes of chow crumb with 45% dextrin, casein, maltodextrin, or calcium caseinate added or with no nutrient added. The usual effect of fenfluramine was to reduce the intake preference for a coarser over a finer crumb. This drug effect differed, however, with the preparation of protein or of carbohydrate added to each crumb size. There was no consistent effect of nutrient, and hence the reported effects of this dose of dl-fenfluramine cannot be attributed to nutrient-specific selection.

Animals↗
PubMed1991

Hydrophobic surfaces in oligosaccharides: linear dextrins are amphiphilic chains.

Polysaccharide chains are usually considered to be highly hydrophilic, since they have no obvious nonpolar moieties in them. Yet, it is possible to realise conformations in these chains wherein all the hydroxy groups are disposed in one side or face of the chain and the hydrogens disposed in the other. We experimentally demonstrate that such an amphiphilic surface is present in linear oligomeric dextrins, i.e., alpha-1,4-linked D-glucosides, but not in alpha-1,6-D-glucosides (dextrans) or in beta-1,4-D-glucosides (cellulose). This amphiphilicity is generated as a consequence of the stereochemical constraints, which vary with the structure of the sugar and with the type of linkage. Oligosaccharide chains that can adopt incipient helical structures might display amphiphilicity. This property might be relevant to intermolecular recognition on cell surfaces, lectin-sugar binding, antigen-antibody interactions and the like, and might be manifested more in heteromolecular recognition process than as homomolecular self-aggregation.

Carbohydrate Conformation↗
PubMed1977

Production of Schardinger beta-dextrin by soluble and immobilized cyclodextrin glycosyltransferase of an alkalophilic Bacillus sp.

Succinylated cyclodextrin glycosyltransferase (EC 3.2.1.19) of an alkalophilic Bacillus sp. was adsorbed on a vinylpyridine copolymer. The enzyme had about 25% of the activity of soluble enzyme added. No increase of pH or thermal stability of the enzyme was observed by the adsorption, whereas optimum temperature for the enzyme action was shifted from 50 to 55 degrees C. The enzyme converted starch to cyclodextrine without significant loss of activity under the conditions of 4 times reusing of 6 hr conversion by the batch system or 2 weeks continuous reaction by the column system at 55 degrees C and pH 8.0. About 46% of the potato starch solution [15% (w/v)] was converted to cyclodextrins by the enzyme, and 52% was converted by the simultaneous action of the enzyme and alkaline pullulanase of alkalophilic Bacillus sp. (No. 202-1). These values were almost the same as those obtained by the soluble enzyme or enzymes system.

Bacillus↗
PubMed1979

Starch metabolism in Pseudomonas stutzeri. II. Purification and properties of a dextrin glycosyl-transferase (D-enzyme) and amylomaltase.

Amylomaltase and disproportionating enzyme (D-enzyme) were purified to homogeneity from cell-free extracts of Pseudomonas stutzeri using a six-step procedure. The presence of both glycosyltransferases in the same organism has not been reported before. Molecular weight determination by gel chromatography gave a value of 74,000 for the amylomaltase and 115 000 for the D-enzyme. Two subunits of different molecular weight were found in each enzyme as proved by sodium dodecyl sulfate-gel electrophoresis. The optimum pH of amylomaltase and D-enzyme activity is 7.6--7.7. Action of both glycosyltransferases on different maltodextrins showed that amylomaltase is most active with maltotetraose, and the Km value for this substrate is 7.1 mM. D-Enzyme catalyzed glucose release from maltose (Km = 8.3 mM) at a higher rate than from maltotriose and maltotetraose. With maltotriose as initial substrate, D-enzyme forms glucose, maltopentaose, maltoheptaose, maltononaose, maltoundecaose as major products. Amylomaltase acts on maltotriose, maltotetraose, and maltopentaose to form a series of homologous 1,4-alpha-glucans. No essential chain-lengthening reaction occurred with maltohexaose.

Glucans↗