Showing papers on "Guar gum published in 2002"
TL;DR: Pasting curves of starches in gum (hydrocolloid) solutions at low concentrations (starch 3.6%, gum 0.4%) were produced with a Brookfield viscometer as discussed by the authors.
353 citations
TL;DR: In this article, nine polysaccharide gums (sodium alginate, carboxymethyl cellulose, curdlan, gellan, guar gum, gum arabic, κ-carrageenan, locust bean, and xanthan) were compared for their stabilizing effects in sweet potato starch gel against repeated freeze-thawing (FT) treatments.
329 citations
TL;DR: In this article, the graft copolymer (pAAm-g-GG) of guar gum with acrylamide was prepared and crosslinked with glutaraldehyde to form the hydrogel microspheres by the water-in-oil (w/o) emulsification method.
275 citations
TL;DR: Results of the study show that compression-coated tablets containing 80% (FHV-80) of guar gum are most likely to provide targeting of 5-fluorouracil for local action in the colon, since they released only 2.38% of the drug in the physiological environment of the stomach and small intestine.
181 citations
TL;DR: Results of the study show that compression coated metronidazole tablets with either 275 or 350 mg of guar gum coat is most likely to provide targeting of metronidsazole for local action in the colon owing to its minimal release of the drug in the first 5 h.
120 citations
TL;DR: The results indicated that guar gum, in the form of three-layer matrix tablets, is a potential carrier in the design of oral controlled drug delivery systems for highly water-soluble drugs such as trimetazidine dihydrochloride.
109 citations
TL;DR: The above study shows that chitosan could be successfully used as a binder, for colon targeting of water insoluble drugs in preference to guar gum when used in the same concentration.
109 citations
TL;DR: The chain persistence length was found to be insensitive to the degree of galactose substitution and a general value of 9 < C(infinity) < 16 and 3 < L(p) < 5 nm can now be estimated with statistical confidence for all galactomannans.
103 citations
TL;DR: It was found that the physico-chemical nature of added excipients significantly influences the release kinetics from guar-based formulations.
98 citations
TL;DR: The results indicated that guar gum, in the form of three-layer matrix tablets, is a potential carrier in the design of oral controlled drug delivery systems for highly water-soluble drugs such as metoprolol tartrate.
98 citations
TL;DR: In this article, the rheological behavior and synergistic character of mixed polysaccharide systems are examined for blends of xanthan with enzymatically-modified guar, where the enzyme α-galactosidase is used to selectively cleave off the galactose side chains of guar in order to obtain galactomannans with tailored molecular architecture.
TL;DR: In this article, Sensory paired comparison tests were used to study differences in taste intensity in solutions of hydroxypropylmethyl cellulose (HPMC) at concentrations above (1.0% w/w) c*, the coil-overlap concentration (the point at which viscosity changes abruptly with increasing thickener).
TL;DR: In this article, the effect of deacetylation of O-Acetyl galactoglucomannans (GGM) isolated from thermomechanicalpulp (TMP), as well as enzymatically modified guar gum galactomans (GM) were used in the study.
Abstract: Sorption of mannans onto bleached kraft pulp (BKP) was investigated withreference to other interactions of mannans in mechanical pulping andpapermaking. O-Acetyl galactoglucomannans (GGM) isolated from thermomechanicalpulp (TMP), as well as enzymatically modified guar gum galactomannans (GM) wereused in the study. The results showed that deacetylation of TMP GGMs, alsooccurring during peroxide bleaching of TMP, dramatically increased thesorption.A higher sorption was also achieved after salt addition, while temperature hadno effect. Sorption of guar gum GMs onto BKP fibres was, on the other hand,quite unaffected by external conditions such as temperature, pH and saltaddition. The degree to which the pulp was beaten did not notablyinfluence the sorption either – only unbeaten pulp gave a clearly lower mannansorption. A lower number of galactose side groups, however, strongly affectedsorption – the lower the number of side groups, the higher the sorption.The molar mass did not seem to affect the rate of sorption to any higher extentat ambient temperature. At higher temperatures the rate of sorption of smallerGM polymers was, nevertheless, slightly increased. Low-molar-mass GMs alsosorbed at a higher rate onto unbeaten pulp compared to high-molar-mass mannans.GM sorption appeared to be virtually irreversible.
TL;DR: Ionic cross-linking of sodium carboxymethyl guar gum as a mild method for microencapsulation of sensitive drugs, like proteins, is presented and trivalent metal ions like Al and Fe were found to be superior to divalent metal ions.
Abstract: Ionic cross-linking of sodium carboxymethyl guar gum as a mild method for microencapsulation of sensitive drugs, like proteins, is presented. When a solution of sodium salt of carboxymethyl guar gum, containing BSA as a model drug, is added, as droplets, to different multivalent metal ion solutions, they get cross-linked to form insoluble microbeads. The amount of protein retained, morphology of the resulting beads and the subsequent release of the retained protein is simulated intestinal fluids varied with the type of metal ion as well as it's concentration. Trivalent metal ions like Al +++ and Fe +++ were found to be superior to divalent metal ions like Ba ++, Ca ++, Cu ++ and Cd ++ . The optimum concentration around which these ions provide maximum drug retention was found to be much lower for trivalent ions. Beads cross-linked with them released the protein over a longer duration in enzyme free simulated intestinal fluid, than those cross-linked with divalent ions. Mg ++, Sr ++, Co ++ and Zn ++ failed...
TL;DR: In this article, a mixture of guar gum (PAAm-g-GG) and Na-Alg was used for pervaporation separation of water-isopropyl alcohol mixtures over the entire range of mixture composition at 30°C.
Abstract: The blend membranes of sodium alginate (Na-Alg) and poly(acrylamide)-grafted guar gum (PAAm-g-GG) in the ratios of 3:1 and 1:1 were prepared and studied for the pervaporation separation of water–isopropyl alcohol mixtures over the entire range of mixture composition at 30°C. Membranes prepared from neat Na-Alg (M-1) and the 1:1 blend of Na-Alg and PAAm-g-GG (M-3) showed the highest separation selectivity for 10 mass % water in the feed mixture, whereas membranes prepared with the 3:1 blend ratio of Na-Alg to PAAm-g-GG showed the highest separation selectivity of 20 mass % water in the feed. Selectivity decreased with increasing amount of water in the feed for all the membranes, but these values show an increase with increasing amount of grafted copolymer in the blend mixture. Flux increased with increasing amount of water in the mixture, but the flux values did not change markedly with the PAAm-g-GG content in the blend membrane at the lower mass % water. At higher mass % of water, the flux values of the blends increase systematically with increasing amount of PAAm-g-GG in the blend polymer. For the 10 mass %-containing binary mixtures, the pervaporation separation experiments were performed at 30, 40, and 50°C, and the resulting data were used to calculate the Arrhenius activation parameters. These data indicated activated pore-type diffusion of the permeants in the membranes. Dynamic sorption studies were also performed on up to 40 mass % water–isopropyl alcohol mixtures at 30°C. These results, when analyzed by the empirical equation, indicated Fickian transport in all the cases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2014–2024, 2002
TL;DR: Intrinsic viscosities and Huggins' coefficient values were substantially different, depending on the purification method used, and were attributed to differences in fine structure.
TL;DR: In this paper, borate crosslinked guar gels were prepared at three different pHs to understand the relationship between fluid characteristics and its solids transport and sand suspension capabilities.
TL;DR: A synthetic formulation has been developed with viscosity, spinnbarkeit, and pH comparable to that reported for human cervical mucus, shown to be critical factors in the performance of the formulation.
TL;DR: In this article, the authors investigated the hydration kinetics of four commercially produced guar gum powders using viscosity development as an index of hydration rate, using three empirical hydration models: (1) first-order kinetics; (2) logarithmic; and (3) the Weibull function.
TL;DR: In this article, the effect of different hydrocolloids viz. guar gum, sodium alginate, pectin, CMC (carboxy methyl cellulose), xanthan gum and gum acacia on the consistency index, serum loss and flow value of tomato ketchup during storage at 5 and 50°C was studied.
Abstract: The effect of different hydrocolloids viz. guar gum, sodium alginate, pectin, CMC (carboxy methyl cellulose), xanthan gum and gum acacia on the consistency index, serum loss and flow value of tomato ketchup during storage at 5 and 50°C was studied. All hydrocolloids increased consistency of tomato ketchup, however, guar gum and xanthan gum caused maximum increase followed by CMC, sodium alginate, gum acacia and pectin. The consistency of tomato ketchup decreased with the increase in storage duration and the decrease was more pronounced at 50°C as compared at 5°C. Both serum loss and flow value decreased with the addition of all the hydrocolloids and increased with the increase in storage duration and temperature. Xanthan gum and guar gum caused maximum decrease in serum loss and flow value whereas pectin caused the least. Regression analysis was also performed to compute models which can be used to predict the effect of each hydrocolloid on consistency index, serum loss and flow value of tomato k...
TL;DR: In this article, the authors investigated the effect of various cryoprotectants such as xanthan gum, guar gum, pectin, carrageenan, sodium caseinate, whey protein concentrate, and dairy powders on a variety of vegetables.
Abstract: Summary Freezing and thawing have been shown to adversely affect the centrifugal drip loss and maximum resistance to penetration of cooked, pureed vegetables (potatoes, carrots and turnips). Amelioration of these effects has been investigated through the addition of cryoprotectants (xanthan gum, guar gum, pectin, carrageenan, sodium caseinate, whey protein concentrate). The effect of each cryoprotectant varied with vegetable type. In general, gums (xanthan and guar) proved most effective in reducing drip losses although carrageenan and pectin exhibited some ability in this regard. Dairy powders produced no effect on drip loss but did alter maximum resistance values after thawing. Depending on the vegetable, quality maintenance or improvement after thawing may be achieved through selection of an appropriate cryoprotectant.
TL;DR: The results of the study show that the matrix tablets containing either 20 or 30% of guar gum are most likely to target celecoxib for local action in the colon, indicating the susceptibility of the guar Gum formulations to the rat caecal contents.
Abstract: The nonsteroidal anti-inflammatory drugs (NSAIDs) are found to be potential chemopreventive agents of colorectal cancer. Celecoxib, an NSAID with selective cyclooxygenase-2 inhibition, was proved to be effective for the prevention of colon cancer in patients with familial adenomatous polyposis (FAP) and sporadic polyps. In the light of this information, the present study was carried out to develop oral colon-targeting drug delivery systems for celecoxib using guar gum as a carrier. Matrix tablets containing various proportions of guar gum were prepared by wet granulation technique using starch paste as a binder. The tablets were evaluated for hardness, drug content and were subjected to in vitro drug release studies. The amount of celecoxib released from the matrix tablets at different time intervals was estimated by a HPLC method. Guar gum matrix tablets released only 2-4% of celecoxib in the physiological environment of stomach and small intestine depending on the proportion of guar gum used in the form...
TL;DR: The results reveal that programmed drug delivery can be obtained from hard gelatin capsules by systemic formulation approach and that the drug release was also dependant on the type of swellable hydrophilic agent (HPMC or guar gum) and molecular weight of HPMC (K15M or 20 cPs).
TL;DR: In this paper, a side-chain cleaving enzyme, α-galactosidase, is used to cleave off galactose sugar units from guar to produce modified galactomannans with varying galactoses contents of 25.2 and 16.2%.
Abstract: Synergistic biopolymer blends composed of xanthan and enzymatically modified guar galactomannan are investigated in terms of their time-dependent properties. In particular, a side-chain cleaving enzyme, α-galactosidase, is used to cleave off galactose sugar units from guar to produce modified galactomannans with varying galactose contents of 25.2 and 16.2%. Laser scanning confocal microscopy and dynamic rheology are used to monitor the properties of each of these two modified guar gum in solution as well as in blends with xanthan as they are allowed to age over a period of 3 weeks. Our results indicate that solutions of guar with a higher galactose (25.2%) content undergo no rheological change over the period of observation and show a constant gel elastic modulus (G‘) in blends with xanthan. Confocal images of the solutions and the blends also indicate that the systems are stable over a period of 3 weeks. In contrast, guar gum with a lower galactose content (16.2%) forms interchain associations in solutio...
TL;DR: In this paper, the phase transition behavior of neutral galactomannans, i.e., locust bean gum (LBG), tara gum (Tara-G) and guar gum (GG)-water systems is investigated.
Abstract: Phase transition behaviour of neutral galactomannans, i.e., locust bean gum (LBG), tara gum (Tara-G) and guar gum (GG)-water systems is investigated. In this study, water content {Wc=(gram of water)/(gram of dry sample)} of these systems was varied from 0.2 to 3.6 g g-1. In the DSC heating curves, glass transition (Tg), cold crystallization (Tcc) and melting (Tm) were observed in all three samples. In addition, liquid crystal transition (T*) was observed in GG-water systems at a temperature higher than Tm. Using Tg, Tcc, Tm and T*, phase diagrams of each system were established. From the melting enthalpy of ice in the systems, three types of water, non-freezing water (Wnf), freezing bound water (Wfb) and free water were calculated. The maximum amount of Wnf was observed at Wc=0.7 g g-1, where Tg showed the lowest temperature. The amount of Wnf in LBG and GG is higher than that of Tara-G, whereas the highest amount of Wfb is found in GG. T* was only observed in GG-water systems. It is concluded that frequency of the side chains in the repeating unit of the main chains of these three galactomannan affects the frozen structure of the glassy state in the presence of water.
TL;DR: Addition of different dietary fibres to a solid meal did not influence gastric emptying and orocaecal transit time and there was a poor, but significant, correlation between gas production and symptoms.
TL;DR: The delayed T(max), decreased C(max) and K(a), unaltered bioavailability, and prolonged t(1/2) and MRT indicated a slow and prolonged release of trimetazidine dihydrochloride from guar gum three-layer matrix tablets in comparison with the immediate release tablet dosage form.
TL;DR: The flow behavior index (n) of all the mixes having optimum levels of various stabilizers was observed to be less than 1; indicating theirpseudoplastic nature.
Abstract: Ice cream made with buffalo milk, using optimum levels of various stabilizers of plant origin, was evaluated for its flow behavior characteristics, with the objective of producing an acceptable quality product. The minimum variation in the viscosity of mix was observed at three rates of shear (348.88, 523.33 and 1046.66 S(-1)) for all ice cream mixes. The flow behavior index (n) of all the mixes having optimum levels of various stabilizers was observed to be less than 1; indicating their pseudoplastic nature. Consistency coefficient (m) of sodium alginate was found to be 1.19; highest among all the stabilizers, followed by gelatin (1.17), karaya (1.08), guar gum (0.75), acacia gum (0.70), ghatti gum (0.36), and the control (0.29). The consistency coefficient (m) signifies the apparent viscosity of the pseudoplastic fluid. The viscosity of the mixes having various stabilizers (optimum levels) was found to be in descending order: Sodium alginate, gelatin, karaya, guar gum, acacia, ghatti and control.
TL;DR: In this paper, the turbulent drag reduction characteristics in a rotating disk apparatus were investigated by using polysaccharide guar gum in deionized water, and the ultrasonic degradation method was adopted to obtain different molecular weight fractions of guar Gum for this study.
Abstract: The turbulent drag reduction characteristics in a rotating disk apparatus were investigated by using polysaccharide guar gum in deionized water. The ultrasonic degradation method was adopted to obtain different molecular weight fractions of guar gum for this study. The stability of guar gum over time was observed to be better than the typical synthetic water-soluble drag reducers [e.g., poly(ethylene oxide)]. A linear correlation between polymer concentration and the concentration/(drag reduction) for different molecular weights of guar gum was obtained, and the universal drag reduction curve for the guar gum/deionized water system was constructed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2938–2944, 2002; DOI 10.1002/app.10300
TL;DR: In this article, the authors used viscometry, texture analysis, and centrifugation to investigate the effects of chain conformational changes of xanthan or deacetylated Xanthan gum on its interaction with guar gum.
Abstract: :
Ubbelohde viscometry, texture analysis, and centrifugation were used to investigate the effects of chain conformational changes of xanthan or deacetylated xanthan gum on its interaction with guar gum. Guar gum was not effective in denaturing xanthan gum when the xanthan helical structure was stabilized by salt. The intrinsic viscosities of deacetylated xanthan and guar blends were higher than those calculated from the weight averages of the 2. Conformational change was not observed for deacetylated xanthan, presuming deacetylated xanthan was in the exact conformation for guar to bind so that the most stable heterotypic structure between deacetylated xanthan and guar was formed directly, thus the strongest interaction was observed between deacetylated xanthan and guar.