Composition Of Gum Research Articles

45. Gummosis induced by jasmonates in plum (Prunus domestica) fruits : Relevance to hormonal regulation and chemical composition of gums

45. Gummosis induced by jasmonates in plum (Prunus domestica) fruits : Relevance to hormonal regulation and chemical composition of gums

Magnetic Fe3O4 @ silica–xanthan gum composites for aqueous removal and recovery of Pb2+

A magnetic Fe3O4 @ silica–xanthan gum composite was easily fabricated as a hybrid adsorbent for the removal and recovery of aqueous Pb2+ heavy metal. The natural polymer xanthan gum (XG) was fixed on the surface of the magnetic Fe3O4 microspheres through a sol–gel process. The condensation of XG molecule provided active sites for the selective adsorption of Pb2+ ions from the aqueous solution, and because the composite is magnetically switchable, the process of solid–liquid separation was convenient. Scanning electronic microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, thermogravimetry, and BET surface area determination were utilized for the characterization of the composites. The factors affecting Pb2+ adsorption in a batch mode were studied including the contact time (30–150min), the pH of the media (2–10), the adsorbent dosage (0.01–0.2g/20mL), and the temperature (303–320K). The Pb2+ adsorption followed pseudo-second-order kinetics, and the maximum Pb2+ sorption capacity was 21.32mgg−1 at 293K, pH=6, according to the Langmuir isotherm. The thermodynamic parameters, including the equilibrium constant (K0=9.848), the standard free energy change (ΔG0=−5.774kJmol−1), the standard enthalpy change (ΔH0=6.133kJmol−1), and the standard entropy change (ΔS0=39.21Jmol−1K−1) were discussed. The targeted Pb2+ could be recovered efficiently using 0.05molL−1 HCl. Finally, the Fe3O4 @ silica–XG composites were attmepted for removal of Pb2+ from battery industry wastewater.

Chemical Structure and Rheological Properties of Tara Polysaccharide Gum

Tara gum is a natural hydrocolloid obtained by a mechanical process from the endosperm of Tara tree seeds. In this study, chemical composition and structure of tara polysaccharide gum were characterized by fourier transform infrared spectroscopy (FT-IR) and gas chromatograph-mass spectrometer (GC-MS). Its rheological properties were also discussed. The results showed that tara gum had typical characteristics of plant polysaccharides, which was mainly consisted of galactose and mannose (mass ratio of galactose/mannose was 4.2:1), as well as a small amount of arabinose, glucose and xylose. The viscosity of tara gum solution was increased with the increase of its concentration. The tara gum solution demonstrated a higher viscocity at the shear rate lower than 80 Hz, but a higher elasticity at the shear rate higher than 80 Hz.

Spectral Database for Postage Stamps by Means of FT-IR Spectroscopy

A Fourier transform infrared (FT-IR) spectroscopy study on the entire Italian postage stamps production is presented in this work. Crossing 150 years of issues from the unification of Italy until today, a time line of the major components constituting the stamps has been defined, based on the wide spectral database built on the basis of the numerous analyzed exemplars. Even though it is easy to find reports about stamps' issues history, information arising from these investigations contributes to throw light upon the substances incorporated in the stamps, which could be described as hybrid or composite materials (a sort of undisclosed or hidden story). As a result of the whole spectra acquired in attenuated total reflectance (ATR) mode, changes in paper composition showed the transition from the protein sizing glue to starch sizing; also the employment of kaolin varied through time. First it was used as the extender in the pigment-medium mixture, and finally it constituted the coating on the stamp surface. Also the chemical composition of the adhesive gum on the rear side of stamps has been subjected to modifications, as well as the front side. The earliest back glue was a protein-based adhesive; then it was replaced by gum arabic first and by poly(vinyl acetate) (PVAC) later. FT-IR spectroscopy, supported by the detailed database developed, has been applied, for the first time, in the very useful detection of two counterfeit samples: a fake of the famous Gronchi Rosa, issued in 1961, and a regummed 2 cent red stamp, issued in 1865. The information held in the whole spectral data has been selected and employed in the principal component analysis (PCA) statistical analysis.

TULIPOSIDES AND TULIPALINS IN TULIP GUM

Gummosis in tulip bulbs is one of the negative effects of ethylene gas that is produced during storage by Fusarium-infected bulbs on the healthy bulbs. Several aspects of the gummosis process, like the factors inducing it, the underlying carbohydrate metabolism and the composition of the gum have been described in detail in a review by Saniewski et al. (2007). The composition of tulip gum has mostly been studied in terms of large macromolecules. The gum polysaccharides have been analyzed to determine sugar composition and molecular mass. Up to now relatively little was known about the gum in terms of small (low molecular weight) metabolite content. Gummosis was induced in tulip bulbs of the cultivar ‘Apeldoorn’ by exposing the bulbs to air containing 30 ppm ethylene for 24, 48 or 72 h. Gum was collected after 3 to 4 days. A maximum amount of approximately 5 g per 100 g bulbs was obtained. Extracts of the gum were analyzed by 1H Nuclear Magnetic Resonance (1H NMR) and were found to contain tuliposides, in concentrations up to around 25% (DW). Tuliposides are glycosides consisting of glucose with one or more a-methylene-?-butyrolactone side chains. The side chains, when separated from the glucose, form ring structures known as tulipalins. Six different tuliposides and two tulipalins have been reported in various parts of the tulip plant. However, this is the first time they are reported in the gum from tulip bulbs. Isolated tulipalins and tuliposides have previously been tested for various bioactivities, and have been reported to possess antibacterial, antifungal and insecticidal properties. The presence of these bioactive molecules in tulip gum may suggest a protective role for this physiological response

Rheological characterization of galactomannans extracted from seeds of Caesalpinia pulcherrima

The galactomannan from the seeds of Caesalpinia pulcherrima L. was isolated and purified by precipitation method using alcohol to get C. pulcherrima (CP) gum. CP gum was studied for its physicochemical and rheological properties. The composition of CP gum was found to contain mannose:galactose:glucose:xylose in a proportion of 2.8:1:0.1:0.08, with M/G ratio 2.80. The molecular weight (Mw) for CP gum was obtained to be approximately 2.72×106Da by static light scattering measurements and 2.79×106Da using Mark–Houwink relationship. The intrinsic viscosity by Huggins and Kraemer plots using capillary viscometry was obtained as 12–12.5dl/g. The rheological behavior of aqueous galactomannan solutions was studied at 25°C, using steady-shear and dynamic oscillatory measurements. The various concentrations of CP gum exhibits shear thinning non Newtonian behavior at high shear rate and Newtonian flow at low shear rate. Experimental data in steady shear has been correlated and found a better fitting with the Cross and Carreau models. A graph of the specific viscosity at zero shear rate (ηsp0) against coil overlap parameter (C[η]) was plotted and the slope of the lines in dilute and semi-dilute regions were found to be 1.23 and 4.1 respectively. The critical concentration (C*) was found to be about 3.8/[η]. The linear viscoelastic region for CP gum solutions presented nature as that of macromolecular solutions. At all shear rates and frequencies, ηap and η* had almost similar magnitudes, which shows its reasonable agreement with the Cox–Merz rule. The present investigation shows the suitability of CP gum as a pharmaceutical aid application like viscosity modifier, release retardants, binders.

Preparation and Technological Evaluation of Methacrylic and Polyacrylic Acid/Leucaena Gum as a Thickener in Printing Protein Fibre

Polymethacrylic or polyacrylic acid/leucaena gum composites were prepared via grafting methacrylic acid monomers onto the galactomannan gum, isolated from leucaena seeds, using ammonium persulphate as an initiator. The rheological properties, in addition to the suitability of the composite for the direct printing of protein fabrics with acid or reactive dyes, were thoroughly investigated. It was found that polymethacrylic or polyacrylic acid/leucaena gum pastes are characterized by a non-Newtonian pseudoplastic behaviour; the apparent viscosity at a constant rate of shear depends on the neutralization and storage process. The prepared composites could be successfully used in printing wool and silk, regardless of the nature of the fabric. The K/S depends on the degree of neutralization of the composite employed as well as the storage time. The colour fastness properties to washing, rubbing and perspiration ranges between good to very good.

Tailoring gel modulus using dispersed nanocrystalline hydroxyapatite

Mammalian cells are known to respond to the elastic modulus of the surface to which they adhere. Consequently, there is interest in developing strategies to control the elastic moduli of materials, including hydrogels. One way of controlling modulus in hydrogels is to introduce reinforcing agents such as inorganic materials, for example hydroxyapatite (HA). Although several authors have reported the reinforcement of hydrogels with ceramic particles, there have not been any studies to investigate the effect of size and crystallinity of HA particles on the mechanical properties of hydrogel. In this study, synthetic Calcium phosphate of two different crystallite sizes: one on the nano-scale (∼50 nm) and the other on the micro-scale (∼150 nm) have been used to manufacture HA/gellan gum (GG) composites. It was shown that while nano-scale HA (nHA) reinforced the hydrogel structure, the micro-scale HA (mHA) material acted to weaken it (2.5 wt% HA). Furthermore, it was found that by increasing the content of the nHA in the composite to 50 wt%, the yield strength and bulk modulus was increased by four- and nine-fold, respectively. The reinforcing effect of nHA was attributed to its higher association with the GG coil structure when compared with the mHA, which disrupted gel structure.

Stabilization of emulsions by gum tragacanth (Astragalus spp.) correlates to the galacturonic acid content and methoxylation degree of the gum

Gum tragacanth samples from six species of Iranian Astragalus bush plants (“goat's-horn”) were evaluated for their emulsion stabilizing effects and their detailed chemical composition in order to examine any possible correlation between the make-up and the emulsion stabilizing properties of gum tragacanth. The six gum tragacanth samples were exudates from the species Astragalus parrowianus, Astragalus fluccosus, Astragalus rahensis, Astragalus gossypinus, Astragalus microcephalus, and Astragalus compactus. The six gum samples varied with respect to their levels and ratios of water-soluble (tragacanthin) and water-swellable (bassorin) fractions, their monosaccharide composition, methoxylation, and acetylation degrees. The gums from A. parrowianus and A. fluccosus had relatively high tragacanthin:bassorin ratios of ∼66:34 and ∼75:25, respectively, whereas in the other gums this ratio approached 50:50 (A. rahensis, A. microcephalus, A. compactus) or tipped toward higher bassorin than tragacanthin (A. gossypinus). The monosaccharide make-up of the six gums also varied, but all the gums contained relatively high levels of galacturonic acid (∼100–330 mg/g), arabinose (50–360 mg/g), xylose (∼150–270 mg/g), and galactose (∼40–140 mg/g), and also contained fucose, rhamnose, and glucose. The ability of the gums to act as stabilizers in whey protein isolate based emulsions varied. The best emulsion stabilization effect, measured as lowest creaming index ratio after 20 days, was obtained with the A. fluccosus gum. The emulsion stabilization effect correlated linearly and positively to the methoxylation degree, and galacturonic acid content of the gums, but not to acetyl or fucose content. A particularly high correlation was found between methoxyl level in the soluble gum part and emulsion stabilization. The work provides some important clues to the emulsion stabilization mechanisms in relation to the monosaccharide composition of tragacanth gums.

Preparation of Cellulose Fiber/Cationic Guar Gum Composites by Wet-Hot Pressure Technology

In this study, the high density 900kg/m3 biodegradable cellulose fiber composites have been successfully manufacture from treated cellulose fiber by wet-hot pressure technology. The cellulose fiber was treated with cationic guar gum(CGG) by the process of adsorption. It was found that the composite made from treated cellulose fibers have better mechanical properties such as the tensile properties and stiffness. Chemical groups of samples were studied through the use of FTIR spectroscopy.

The Instability of Storage of Middle Distillate Fuels: A Review

The author reviews the research studies that have been so far carried out and reported in the literature on the stability of middle distillate fuels. The emphasis is mainly given to understand the stability of diesel fuels. It has been divided into five principle sections: (a) Introduction, (b) Methods for Determination of Fuel Stability, (c) Mechanism of Degradation, (d) Composition of Total Gum, and (e) Current Status of Methods to Improve Fuel Stability. The introduction provides information of in-stabilization of distillate fuel that depends on the various blending streams of middle distillates in the introduction part. In the second section the author elaborate the methods so far used to determine the instability of middle distillate fuels. The third section serves the elaborated mechanism of degradation, the role of chemical composition of distillate fuels, and the responsible components in distillate fuels that impart in degradation of distillate fuels. The fourth section comprises the composition of material formed during degradation and the fifth section of reveals the current status of methods used to improve the stability. In combination, these five sections would provide a ready reference source of data available in the literature on diesel fuel stability.

Contribution of the cashew gum (Anacardium occidentale L.) for development of layer-by-layer films with potential application in nanobiomedical devices

The search for bioactive molecules to be employed as recognition elements in biosensors has stimulated researchers to pore over the rich Brazilian biodiversity. In this sense, we introduce the use of natural cashew gum (Anacardium occidentale L.) as an active biomaterial to be used in the form of layer-by-layer films, in conjunction with phthalocyanines, which were tested as electrochemical sensors for dopamine detection. We investigated the effects of chemical composition of cashew gum from two different regions of Brazil (Piauí and Ceará states) on the physico-chemical characteristics of these nanostructures. The morphology of the nanostructures containing cashew gum was studied by atomic force microscopy which indicates that smooth films punctuated by globular features were formed that showed low roughness values. The results indicate that, independent of the origin, cashew gum stands out as an excellent film forming material with potential application in nanobiomedical devices as electrochemical sensors.

Dielectric behaviour and pore size distribution of collagen–guar gum composites: Effect of guar gum

Abstract Collagen is usually combined with other biopolymers to enhance its physico-chemical properties for tissue engineering applications. In this study, guar gum, a non ionic plant derived polysaccharide was mixed with collagen and the effect of the same on dielectric behaviour and pore size distribution of the composites has been investigated. Circular dichroic studies show that guar gum does not bring any alteration in the conformation of the native protein. Thermoporometry result shows that by varying the concentration of guar gum, the pore size distribution of the biocomposite can be controlled. The thermal stability of biocomposite system increases as the concentration of guar gum increases and reaches a maximum of 40 ± 0.5 °C. Initiation of the polarization mechanism through the ionic charge drift on the protein-additives interfaces is affected due to the guar gum concentration, which influences the hydration shell of the protein molecule.

Optimization of low-cholesterol–low-fat mayonnaise formulation: Effect of using soy milk and some stabilizer by a mixture design approach

In the present study, the optimized mixture proportions of low cholesterol-low fat mayonnaise contained soy milk as an egg yolk substitute (10%) with different composition of xanthan gum (XG), guar gum (GG) and mono- & diglycerides emulsifier (MDG) (0–0.36% of each component) were determined by applying the simplex-centroid mixture design method to achieve the desired stability, textural and rheological properties and sensory characteristics for effective formulation process. Results revealed that the best mixture was the formulation contained 6.7% mono- & diglycerides, 36.7% guar gum and 56.7% xanthan gum. The xanthan gum was the component showing the highest effect on all the properties of mayonnaise samples. In addition, an increase of xanthan gum followed by guar gum caused greater values for the stability, heat stability, consistency coefficient, viscosity, firmness, adhesiveness, adhesive force and overall acceptance and lower value for flow behavior index. Depending on the desirable level of xanthan gum, guar gum and mono- & diglycerides, creation of low cholesterol-low fat mayonnaise with properties closely matching those of commercial ones is possible.

Impact of chemical composition of xanthan and acacia gums on the emulsification and stability of oil-in-water emulsions

Xanthan gum (GX) and acacia gum (GA) are widely employed in food industry, indeed xanthan gum is used for its thickening properties of aqueous solutions and acacia gum for its emulsifying ability. The present work aims to study the effect of GX–GA mixtures on the stability of oil-in-water (o/w) emulsions; attention is particularly focused on the impact of the chemical structure of each gum. Emulsion stability has been evaluated by monitoring the evolution of droplet size and viscometric properties over time when submitted to accelerated ageing conditions. On the one hand results show that the higher the ArabinoGalactanProtein (AGP) content the more stable the emulsion as observed when GA is used alone. On the other hand, we proved, unexpectedly, that the most viscous aqueous phase does not exhibit the best emulsion stability. Besides, we clearly evidenced the presence of specific interactions between GX and GA in both emulsion and aqueous solution, these interactions being governed by the gums chemical composition.

Guar gum: processing, properties and food applications—A Review

Guar gum is a novel agrochemical processed from endosperm of cluster bean. It is largely used in the form of guar gum powder as an additive in food, pharmaceuticals, paper, textile, explosive, oil well drilling and cosmetics industry. Industrial applications of guar gum are possible because of its ability to form hydrogen bonding with water molecule. Thus, it is chiefly used as thickener and stabilizer. It is also beneficial in the control of many health problems like diabetes, bowel movements, heart disease and colon cancer. This article focuses on production, processing, composition, properties, food applications and health benefits of guar gum.

Avaliação do bis(4-metilfenilditiocarbimato)zincato(II) de tetrabutilamônio como acelerador no processo de vulcanização do elastômero polibutadieno

O ZNIBU, acelerador de caráter lento foi avaliado neste trabalho em composições de polibutadieno. Este acelerador foi sintetizado com o objetivo de substituir, ou reduzir, o uso de alguns aceleradores comerciais muito utilizados em composições elastoméricas mas que, por serem formadores de nitrosaminas, podem ser prejudiciais à saúde. A fim de corrigir o caráter de acelerador lento do ZNIBU, este composto foi utilizado em conjunto com o acelerador comercial CBS (N-ciclohexil-2-benzotiazol-2-sulfenamida). Foi observado que pequenas quantidades dos dois aceleradores não são efetivas na aceleração da vulcanização nas composições do tipo goma pura. No entanto a presença de negro de fumo exerce um efeito positivo sobre a velocidade. As propriedades mecânicas estudadas mostram que o ZNIBU aumenta a resistência à tração da goma pura (35%), em comparação com a composição similar vulcanizada com CBS e, na presença do negro de fumo, este aumento é ainda mais expressivo (175%). Quanto à resistência ao rasgamento, a vulcanização com o ZNIBU forneceu o mais baixo valor da propriedade para a goma pura, enquanto que a composição com negro de fumo apresentou o mais alto valor.

Preparation of anatase nano‐TiO2/xanthan gum composite (NTX) and rheological study of the interior wall coatings using NTX as additive

PurposeThe purpose of this paper is to develop a kind of novel and high‐performance rheological additive, an eco‐friendly composite of anatase nano‐TiO2 particles and xanthan gum (NTX), for interior wall coatings.Design/methodology/approachNTX was prepared through heating and refluxing the mixture of TiO2 hydrosol and xanthan gum, and five interior wall coating samples were fabricated with different NTX contents. The morphology of nano‐TiO2 hydrosol and NTX were characterised with TEM, and the stability and rheological properties of these coating samples were studied.FindingsTEM images showed a core‐shell structure of NTX, and that nano‐TiO2 particles in it were encapsulated by xanthan gum, which was anticipated to weaken Van der Waals force among nano‐TiO2 particles thus preventing the aggregation of nano‐particles. All of the five coating samples were found to be non‐Newtonian pseudo‐plastic fluid, and showed excellent stability and thixotropic property.Research limitations/implicationsThis paper focused on the preparation, the characterisation of NTX additive and the study of the rheological behaviours of the coating samples with NTX. Some other aspects, such as coating durability, photocatalytic ability and film properties, will be studied in the future.Practical implicationsIt was proven that NTX was an effective eco‐friendly rheological additive for interior wall coatings. Consequently, this paper threw light on developing eco‐friendly interior wall coatings.Originality/valueA kind of novel and effective rheological additive was developed for interior wall coatings in the study reported in the paper. A method was also developed to introduce functional nano‐particles into coating in a good dispersion state.

Comparative study on the role of Food gums in the production of Cocoa-enriched Candies.

Proximate composition and functional properties of food gums (gelatin and corn starch) and cocoaenriched candies made with and without the food gums were analysed. Gelatin was richer than corn starch in protein (49.60%), crude fibre (2.56%) and moisture (7.46%) while corn starch was higher in carbohydrate (76.28%). Gelatin exhibited significantly higher water absorption (10g/g), and emulsifying capacity (43.09%) and stability (18.66%) than corn starch (28.80% and 17.35% respectively). Corn starch exhibited better gelation capacity (2.5%) than gelatin (0.5%) and had a higher bulk density (0.6g/cm). Non gum-based candy contained higher percentages of protein (5.98%), crude fibre (1.52%) and moisture (7.90%) with better, emulsifying and oil absorption properties than gum-based candies. Gelatin-based candy had the best bulk density compared to corn starch and non gum-based candies and exhibited higher carbohydrate and moisture contents than corn starch-based candy. Gelatin having a better functionality gave a more acceptable product compared to corn starch. This study showed that apart from the added health benefits of gums to foods, candies could be made without food gums as the non gum-based candy compared favourably with the gum-based candy in physical characteristics.Key words: Candy; Gums; Functional properties

Evaluation of properties of unsaturated polyester/acetylated hydroxypropyl guar gum composites

AbstractGuar gum is a naturally occurring galactomannan, which is extremely hydrophilic in nature. Hydroxypropyl guar gum (HPG) was subjected to acetylation using acetic anhydride and pyridine. The effect of the reduction in the hydrophilic nature of the polymer on its filler properties was studied by using the derivatized guar gum as filler in an unsaturated polyester composite. The effect of degree of substitution and the concentration of filler on the rheological, chemical, and mechanical properties of the composites were studied. Results indicated that an increase in the acetate content in the HPG resulted in an increased polymer–filler interaction. However, the composites resulting from these derivatized HPGs showed reduced mechanical properties. This decrease in the mechanical properties were attributed to the decrease in the hydrogen bonding in the filler particles, thus reducing the cohesiveness and strength of the filler particles themselves. Thus, polysaccharides can be used as fillers but chemically modifying them results in a change in the basic nature of the filler itself and is not just restricted to surface modification as is the case of inorganic fillers and fibers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010