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Characterization of commercial samples of gum arabic
Abstract
Six commercial gum arabic samples and authenticated samples of gum from Acacia senegal and Acacia seyal have been characterised using a range of chemical and physicochemical techniques including determination of specific rotation, sugar composition, nitrogen and amino acid content, and molecular mass distribution. Although some of the gums have slightly different chemical and physicochemical characteristics, gel permeation chromatography shows that each consists of essentially three molecular mass fractions classified as an arabinogalactan, an arabinogalactan-protein complex, and a glycoprotein. The proportions of each varied for the individual samples. The gums were tested using a specifically developed enzyme-linked immunosorbent assay which can identify gum from A. senegal and chemically related species. Their interaction with the antibody could be correlated with differences observed in their molecular compositions. Such evidence will assist in their chemotaxonomic classification.
... The results also showed the presence of metal elements such as manganese, lead, zinc, potassium, calcium, magnesium, copper, cadmium, nickel and iron. These results are similar to the finding of Islam et al. [42], Anderson, et al [43] and Osman, et al [44] who reported that the major elements present in Acacia senegal were Ca, Mg, Na, K, Fe, and Cu. However, the metal elements Mn, Pb, Zn, Cd, Ni which were detected in this research work were not detected by Islam, et al [42], Anderson, et al [43] and Osman, et al [44]. ...
... These results are similar to the finding of Islam et al. [42], Anderson, et al [43] and Osman, et al [44] who reported that the major elements present in Acacia senegal were Ca, Mg, Na, K, Fe, and Cu. However, the metal elements Mn, Pb, Zn, Cd, Ni which were detected in this research work were not detected by Islam, et al [42], Anderson, et al [43] and Osman, et al [44]. Acacia senegal is a complex mixture of polysaccharides, protein and prabinoglacto protein specie. ...
... It has been shown to be highly heterogeneous and is found in nature as mixed calcium, magnesium, potassium and sodium salts of a polysaccharic acid (arabic acid). However, other heavy elements such as Zn, Al, Cd, Cu, Cr, Pb, and Co may also be present but in very small quantities (Islam,et al [42], Anderson, et al [43] and Osman, et al [44]). However, it is evident that the elemental composition is the main reason which contributes to different colors and appearance of different nodules of the same variety or even within different regions in the same nodule. ...
The study was carried out is to assess the chemical composition of Acacia senegal. The phytochemical and elemental analysis of the leaf extract was also carried out according to standard methods. The results of phytochemical analysis showed that the extract contained carbohydrates, tannins, cardiac glycosides, flavonoids, terpenoids, saponins and alkaloids. The elemental analysis of the plant leaf had concentration levels of the elements (mg/l) manganese (1.56), lead (0.002), zinc (0.57), potassium (60), calcium (56.0), magnesium (24.0), copper (0.22), cadmium (0.05), nickel (0.16) and iron (0.04). The presence of bioactive compounds, low concentrations of mineral elements present in the leaf of Acacia senegal may justify the traditional use of the plant for the treatment of diseases and also the plants may be safe for use as herbal medicine with less concern for toxic effects of heavy metals.
... Not defined 12 (Brito et al., 2004;de Brito et al., 2005;Hall, 2009;Janaki and Sashidhar, 1998;Le Cerf et al., 1990;Stephen et al., 2006;Verbeken et al., 2003;Vinod et al., 2010;Vinod et al., 2008aVinod et al., , 2008bWhistler and BeMiller, 1993) Molecular mass (Da) 1.0 × 10 5 1.6 × 10 6 2 -5 × 10 6 8.9 × 10 7 1.1 × 10 6 (Balaghi et al., 2011;Castellani et al., 2010;Deshmukh et al., 2012;Gavlighi et al., 2013aGavlighi et al., , 2013bIdo et al., 2008;Katayama et al., 2008;Mahendran et al., 2008;Osman et al., 1995, Osman et al., 1993a, Osman et al., 1993bPadala et al., 2009;Padil et al., 2016, Padil et al., 2015bPhillips and Williams, 2000;Randall et al., 1988;C.A. Tischer et al., 2002;Tischer et al., 2002a;Verbeken et al., 2003;Vinod et al., 2008aVinod et al., , 2008b Viscosity (dL/g) 13.2 25.9 ...
... The most significant tree gum exudates that find widespread applications are GA, GK, GT, KG and GG; their morphological appearance and constituent sugar moieties are presented in Fig. 2 and their physical and chemical properties and molecular characterization are shown in Table 2. Extensive research has been conducted on various characteristics including their accessibility, molecular weight assignments, structural linkages, well-designed characteristics (rheological, hydration behavior, self-assembly, and surface properties), food and non-food applications (Anderson and Wang, 1990;Anderson et al., 1985a, 1985b, Anderson et al., 1983Anderson and Bridgeman, 1985;Anderson and Grant, 1988;Anderson and McDougall, 1987;Anderson and Stoddart, 1966;Anderson and Weiping, 1992;Brito et al., 2004;de Brito et al., 2005;Fauconnier et al., 2000;Hall, 2009;Sashidhar, 2000, Janaki andSashidhar, 1998;Kumbhare and Bhargava, 1999.;Le Cerf et al., 1990;Mahendran et al., 2008;Osman et al., 1995, Osman et al., 1993a, Osman et al., 1993bPadala et al., 2009;Philips and Williams, 2001;Phillips and Williams, 2009, Philips and Williams, 2001, Randall et al., 1989, Randall et al., 1989Singh and Sharma, 2014b;Stephen et al., 2006;Vegi et al., 2009;Verbeken et al., 2003;Vinod et al., 2008aVinod et al., , 2008bWeiping, 2000;Whistler and BeMiller, 1993). Tree gums are typically grown under geographically-favorable climatic (excessive heat, shortage of moisture and at higher elevations) and soil conditions (Stephen et al., 2006;Verbeken et al., 2003). ...
... The molecular mainstay comprises 1→3linked β-D-galactopyranosyl parts, whereas the side chain consists of two to five 1→3-linked β-D-galactopyranosyl units (as lateral chains) appended to the backbone via 1→6-linkages. The whole structure is made up of α-L-arabinofuranosyl, α-L-rhamnopyranosyl, β-D-glucuronopyranosyl and 4-O-methyl-β-D-glucuronopyranosyl segments, the last two being the end-terminal units (Anderson et al., 1985a;Fauconnier et al., 2000;Mahendran et al., 2008;Osman et al., 1995, Osman et al., 1993a, Osman et al., 1993bPhilips and Williams, 2001;Phillips and Williams, 2000;Randall et al., 1989;Verbeken et al., 2003). GA is structurally fabricated by high molecular fractions of carbohydrate masses (approx. ...
The prospective uses of tree gum polysaccharides and their nanostructures in various aspects of food, water, energy, biotechnology, environment and medicine industries, have garnered a great deal of attention recently. In addition to extensive applications of tree gums in food, there are substantial non-food applications of these commercial gums, which have gained widespread attention due to their availability, structural diversity and remarkable properties as 'green' bio-based renewable materials. Tree gums are obtainable as natural polysaccharides from various tree genera possessing exceptional properties, including their renewable, biocompatible, biodegradable, and non-toxic nature and their ability to undergo easy chemical modifications. This review focuses on non-food applications of several important commercially available gums (arabic, karaya, tragacanth, ghatti and kondagogu) for the greener synthesis and stabilization of metal/metal oxide NPs, production of electrospun fibers, environmental bioremediation, bio-catalysis, biosensors, coordination complexes of metal-hydrogels, and for antimicrobial and biomedical applications. Furthermore, polysaccharides acquired from botanical, seaweed, animal, and microbial origins are briefly compared with the characteristics of tree gum exudates.
... A typical elution pro®le including light scattering (LS), refractive index (RI) measurements and the corresponding distributions of molecular weight (M w ) as determined by MALLS is presented Fig. 1. Similar pro®les have been obtained previously (Osman, Williams, Menzies & Phillips, 1993;Osman, Menzies, Williams & Phillips, 1994;Ray et al., 1995;Idris et al., 1998;Picton et al., 2000). The RI pro®le indicated that the acacia gum sample consisted in two main molecular species. ...
... For the whole gum sample [h ] 0.23 dl g 21 , which is in the range of the 0.15±0.31 dl g 21 average values found in the literature (Anderson & Rahman, 1967; Swenson et al., 1968;Dickinson et al., 1988;Duvallet, Fenyo & Vandevelde, 1989;Randall et al., 1989;Anderson & Weiping, 1991;Osman et al., 1993;Duvallet, Fenyo & Vandevelde, 1993;Chikamai, Banks, Anderson & Weiping, 1996;Idris et al., 1998;Karamalla, Siddig & Osman, 1998). Regarding the [h] of the AGP and AG fractions, we ®nd 0.87 dl g 21 for the former and 0.18 dl g 21 for the latter. ...
... This gum is composed of a highly tailored polysaccharide salt, constituted by residues of L-arabinose, D-galactose, 4-O-Methyl-D-glucuronic acid and L-rhamnose (Figure 3) [15,16]. Mesquite gum chemical composition is similar (different molar ratio) to that one of Arabic gum, which is commonly employed in the food and pharmaceutical industry, due its emulsification capacity [17,18]. In México, mesquite gum is only consumed as a candy, therefore there is a wield field for exploration of this product as emulsifier. ...
... To carry out this analysis, the Thermo Nicolet 6700 FT-IR spectrophotometer with its attenuated total reflectance accessory (Thermo Scientific) was used, using solid samples (powders). Figure 5 shows the FT-IR spectra of the different gums characterized in this research, which are largely comparable with the FT-IR spectrum of Arabic gum (GA) reported in the literature [17,18]. Therefore, it follows that the different mesquite gums produced (oven dried procedure, dense lyophilized and controlled Lyophilized) essentially have the same chemical composition in terms of sugars, amino acids and proteins. ...
The use of nano-emulsions has great advantages over conventional macro-emulsions since the small droplet size allows to expand the options of applications besides presenting a greater surface area. This chapter focuses on the formulation of nano-emulsions of citrus essential oils in water, stabilized with a natural gum (mesquite gum), using a high pressure microfluidic homogenizer to obtain appropriate physicochemical characteristics and kinetic stability. When establishing the general conditions of the methods for obtaining nano-emulsions by high pressure homogenization, several formulations presented stability and size corresponding to nano-emulsions, and these were monitored during 4 months in order to study their stability as a function of time. Taking into account the results of size and stability, the best nano-emulsion obtained had a composition of Persian lemon oil (9.86%), mesquite gum (4.93%) Tween 80 (4.89%), Span 20 (1.45%), and deionized water (78.86%) with an average droplet size of 40 nm. In addition, the antibacterial activity studies also showed that this formulation had the best performance against common bacteria such as Staphylococcus aureus and Escherichia coli. The analysis of the minimum inhibitory concentration (MIC) shows that it is possible to prevent the growth of these particular bacteria using 6.25% of the best nano-emulsion formulations.
... The formation of semi-IPN involved free radical polymerization for grafting onto gum acacia and sodium alginate (known polysaccharides) followed by crosslinking of grafted chains [22,23]. Initiator created free radical sites on backbone and monomer to start graft copolymerization which get crosslinked to form semi-IPN in the presence of MBA (Scheme 1) [24,25]. ...
... The applicability of Langmuir plot was utilized to evaluate these parameters using Eqs. (20), (21) and (22). K L measuring distribution coefficient calculated using slope m i.e. the adsorbent dose in g L −1 and intercept of Langmuir plot. ...
Gum acacia and sodium alginate were blended to synthesize highly efficient superadsorbent formed by grafting of poly(acrylic acid) (AA) used as monomer onto the hybrid of gum acacia and sodium alginate and the polymeric chains were crosslinked through N,N′-methylene bisacrylamide (MBA). The overall reaction followed free radical polymerization with ammonium persulphate (APS) used as initiator. Response surface methodology integrated with central composite design (RSM-CCD) could synthesize semi-Interpenetrating network (semi-IPN) having maximum swelling capacity of 1749.2% at MBA, APS and AA concentrations of 0.89 × 10−2 mol L−1, 3.29 × 10−2 mol L−1 and 1.46 mol L−1, respectively using 15 mL water at 70 °C for 2.5 h. The synthesized sample was found to be selective for removal of cationic dyes upto 97.49%, 95.39% and 94.56% for auramine-O (AO), malachite green (MG) and crystal violet (CV), respectively. Adsorption capacities at equilibrium were calculated experimentally as 2.01 mg g−1, 3.06 mg g−1 and 7.55 mg g−1 for AO, MG and CV, respectively. These dyes could be desorbed with 0.1 N HCl for the recyclization of semi-IPN. Adsorption mechanism involved monolayer formation with three step process of adsorption and followed first order kinetics. Exothermic nature of adsorption was revealed by thermodynamic studies.
... This could be attributed to the presence of organic acid of gum arabic (El Elhassan, 2017). Osman et al., (1993) stated that higher amount of arabinose and methyl glucuronic acid is present in GA. Similar observation was reported by Hussein (2006) who noticed that the addition of GA reduced pH value of yoghurt, and found that, samples formulated with 2%, 4% and 6% had pH values of 4.57, 4.40 and 4.30, respectively. ...
The study was carried out to evaluate the effect of Arabic Gum (AG) on the physical properties of yoghurt made from powdered milk. Reconstituted powdered milk was pasteurized at 85oC for 30 minutes and then fast-cooled to 42oC. Starter culture MIX505LYODCU (Streptococcus thermophiles and Lactobacillus bulgaricus SSP.) was added at 3% inclusion level, and the mixtures were incubated at 42oC for four hours. Yoghurt samples were formulated with 0%, 5%, 10% and 15% Arabic Gum in a Completely Randomized Design (CRD). After setting, the yoghurt was kept refrigerated at 10oC for 24hrs. Standard analytical procedures were used to determine the physicochemical properties of the product. . Results showed that, powdered milk contained 3.5% moisture, 24.43% protein, 25.66% fat, 28.45% lactose, 3.65% ash, 6.57 pH and acidity of 0.14. Gum Arabic had moisture, protein, ash, and fibre contents of 7.00%, 2.55%, 1.38%, and 1.26% respectively. Increasing the gum level, led to a significant (P≤0.05) decrease in the pH values of the yoghurt, while wheying-offWheyingwas significantly (P<0.05) affected by the gum arabic level. All treated samples were synerisis free. Viscosity increased as gum concentration increasedwith the control sample having the the lowest viscosity of 1213cp, and samples stabilized with 5%, 10% and 15% Gum Arabic (GA) had viscosities of 1260.42. 1326.25 and 1402.50cp respectively. Regarding storage period, the pH- value of yoghurt was significantly (P<0.05)as well as wheying-off of yoghurt and there was significant (P<0.05) reduction in viscosity during storage period.
... The chemical and physical composition of Gum varies varies slightly depending on its origin, climate, harvest season, tree age and processing conditions, such as spray dying (Flindt, Al-Assaf, Phillips, & Williams, 2005;Osman, Williams, Menzies, & Phillips, 1993). The physical properties of Gum established as quality parameters include moisture, total ash, volatile matter and internal energy. ...
The study attempted to use systematic and thematic analysis of reported top 100 cited articles on Gum research. We adopted systematic and thematic analysis using bibliometric analysis tools, such as Scopus database to search relevant documents in Gum. Data were analyzed by RStudio and VOSviewer, and the top 100 cited articles were systematically classified into structural (both chemical and physical), biological, pharmaceutical, food, and cosmetic properties of Gum. The citation times for the 100 top-cited articles ranged from 93 to 457, with an average citation per document of 151.5 scores. The 100 top-cited articles were published in 48 journals, and the journal "Food hydrocolloids" was a top-rank journal with (n = 15) articles followed by "Carbohydrate polymers" (n = 11) articles. Mcclements DJ was the most productive author (6 articles). China the, USA, and India are the most productive countries with more than 30 articles published in Gum. Among 153 contributed affiliations, King Saud University, Saudi Arabia, and Universiti Putra Malaysia, Malaysia were top affiliations in Gum research with more than 14 published articles. The comprehensive analysis shows that about 78% of articles were focused on the structural, chemical and physical properties (9%) of food biological (8%), and on pharmaceutical properties (5%). This is the first bibliometric analysis to provide a historical perspective on Gum scientific research. The systematic and thematic analysis provides comprehensive information on the scientific research direction , hot topics and trends in Gum.
... Recently, it has gained academic interest because of its potential as a spray-drying carrier for the effective pulmonary delivery of next-generation APIs [29][30][31]. Gum arabic is a heterogeneous collection of polysaccharides and glycoproteins with applications as an emulsifying agent, stabilising agent, and tablet binder [32]. Additional interest stems from its reported physico-chemical benefits as an antioxidant and its role in lipid metabolism [33]. ...
Particulate amorphous solid dispersions (ASDs) have been recognised for their potential to enhance the performance of various solid dose forms, especially oral bioavailability and macromolecule stability. However, the inherent nature of spray-dried ASDs leads to their surface cohesion/adhesion, including hygroscopicity, which hinders their bulk flow and affects their utility and viability in terms of powder production, processing, and function. This study explores the effectiveness of L-leucine (L-leu) coprocessing in modifying the particle surface of ASD-forming materials. Various contrasting prototype coprocessed ASD excipients from both the food and pharmaceutical industries were examined for their effective coformulation with L-leu. The model/prototype materials included maltodextrin, polyvinylpyrrolidone (PVP K10 and K90), trehalose, gum arabic, and hydroxypropyl methylcellulose (HPMC E5LV and K100M). The spray-drying conditions were set such that the particle size difference was minimised, so that it did not play a substantial role in influencing powder cohesion. Scanning electron microscopy was used to evaluate the morphology of each formulation. A combination of previously reported morphological progression typical of L-leu surface modification and previously unreported physical characteristics was observed. The bulk characteristics of these powders were assessed using a powder rheometer to evaluate their flowability under confined and unconfined stresses, flow rate sensitivities, and compactability. The data showed a general improvement in maltodextrin, PVP K10, trehalose and gum arabic flowability measures as L-leu concentrations increased. In contrast, PVP K90 and HPMC formulations experienced unique challenges that provided insight into the mechanistic behaviour of L-leu. Therefore, this study recommends further investigations into the interplay between L-leu and the physico-chemical properties of coformulated excipients in future amorphous powder design. This also revealed the need to enhance bulk characterisation tools to unpack the multifactorial impact of L-leu surface modification.
... The conducting polymers have several applications, such as solar materials, sensors, artificial muscles, actuators, electronic shielding and as components in high-energy batteries (Skotheim et al., 1997). The electrical conducting bio-polymers (Mallik et al., 2004), like GA, has the potential for use as raw material for the fabrication of semiconductor-based sensor devices (Osman et al., 1993). Tiwari (2007) carried out radical copolymerization of GA and polyaniline, taking peroxydisulfate as initiator and oxidant. ...
Gum arabic (GA) is the oldest gum known for its diverse application for more than 5000 years. The gum is produced from some species of Acacia, mainly growing/planted in arid and semi-arid regions of Africa and Asia. Sudan is the leading producer and exporter of GA in the world. GA is a mixture of potassium, magnesium and calcium salts of polysaccharide acid and is easily soluble in water. As it possesses a unique biochemical structure and properties, it finds application as a stabilizer, emulsifier, bulking agent, thickener, carrier, glazing and firming agent, humectant and antioxidant. GA is biocompatible and biodegradable, and its source is renewable. The people worldwide are now again feeling the necessity of using natural additives in products of human consumption, due to severe adverse effects of using synthetic additives. Such a shift in the human mindset has created additional demand for natural products like GA. This gum is produced in resource-constrained areas, where people are poor and need the creation of good livelihood options for improvement in their economic conditions. Apart from GA production, Acacia senegal trees help improve soil health and restrict climate change as well as expansion of desert in arid and semi-arid regions. Increasing production of GA by motivating farmers in arid and semi-arid regions to establish Acacia senegal plantations; creating infrastructure for processing and value addition in the regions of GA production; and finding new application areas of GA are urgent needs of this vital sector. This consolidated review on GA covers the current research work on GA production, properties, processing , application and marketing, unlike several specific reviews considering the need of those who want to initiate research work/already working for this sector.
... In general, these chemicals are mainly produced from plants as plant extracts, which are environmentally friendly because they do not contain heavy metals or other toxic metalloids (arsenic), such as organic acids, phenolic compounds, flavonoids, alkaloids, catechins, terpenoids, and coenzymes, etc [7,9,10]. In particular, some phytochemicals obtained from Acacia trees might possess anti-corrosive properties, such as the gum Arabic (GA) containing arabinogalactan as a major component [7,11]. This substance represents a complex polysaccharidebased plant gum exudate, which exists in a form of a multifunctional hydrocolloid with highly branched, neutral, or slightly acidic arabinogalactans together with some proteins containing calcium, magnesium, and potassium [12]. ...
Corrosion prevention in the food industry is a significant issue given the harsh conditions under which many production processes are performed. Therefore, we developed a methodology to test and analyze the novel type of green corrosion inhibitors for mild steel (M.S) in an acidic medium based on the Arabic gum (GA) variants from Morocco (GAMo), Mauritania (GAMau), and Senegal (GASe) in which these three variants were characterized by FTIR analysis, Weight loss (WL) measurements and electrochemical tests such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods were also used to investigate the inhibition power of these compounds for the corrosion of M.S in 1 M HCl. The surface characterization of M.S surface submerged in the optimal solution of the three compounds was carried out using XPS and AFM analyses. The results from this corrosion test demonstrate that these chemical compounds might be used as mixed-type corrosion inhibitors achieving the highest inhibition at 1 g/L, and the ηmax of GAMo, GASe and GAMau reached up to 96%, 95% and 94%, respectively. Spectroscopic and gravimetric analyses revealed that the highest corrosion inhibition for the GAMo variant due to the physical and chemical mechanism according to the pattern: GAMo > GASe > GAMau. The Langmuir adsorption isotherm governs the adsorption of all GA variants on mild steel surfaces, increasing the polarization resistance and inhibition efficiency and decreasing the double-layer capacitance in a concentration-dependent manner. A CPE, Q determined by fit and graphical methods plotted by synthetic data, was utilized. Using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy, the formation of a protective layer on the steel surface was further confirmed (XPS). The final QSAR model for the Arabic gum indicated the same effect of lipophilicity on corrosion inhibition. Overall, the current study provides valuable information on the AG variants to be used as a novel class of green corrosion inhibitors for the biotechnology and food industry.
... The M and r G determined for the GA samples shown in Fig. 2 are summarized in Table 3. The M and r G in Table 3 are in good agreement with those reported in literature where GA was analyzed by size exclusion chromatography (SEC) or AF4 coupled with MALS [28,45], according to which the P-1 and P-2 correspond to arabinogalactan (AG) and arabinogalactan protein (AGP), respectively [28,38,45,46]. The P-3 is likely to be composed of aggregates that could be formed by the self-assembly of AGP and is known to be present in plant secretions containing AGP [32]. ...
1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) is widely used as a crosslinker for fluorescence labeling of protein in the fields of biochemistry and food analysis. Many natural polysaccharides often contain some proteins or peptides that are very low in content but play a vital role in their biological function as well as technical applications. Determination of these low-content proteinaceous matters requires a highly sensitive and selective method. In this study, a methodological approach for investigations of the presence of proteinaceous material over the molar mass distribution ( MD ) of polysaccharides was developed using gum acacia (GA) as a model polysaccharide. EDC fluorescence-labeling method was modified by changing the pH (7, 9, and 11) of the solution for the analysis of low-content protein in food materials. Fluorescence spectroscopy and asymmetrical flow field-flow fractionation (AF4) were employed for characterizing the labeling efficiency and physiochemical properties of unlabeled and fluorescence-labeled GA. AF4 provided molar mass ( M ) and the radius of gyration ( r G ) of arabinogalactan (AG) and arabinogalactan protein complex (AGP) and determined the presence of proteinaceous matter over the MD . The labeling efficiencies of GA at pH 7, 9, and 11 determined by fluorescence spectroscopy were 56.5, 68.4, and 72.0%, respectively, with an increment of 15.5% when pH was increased from 7 to 11. The modified EDC fluorescence-labeling method allows highly sensitive and selective analysis of low-content proteinaceous matters and their distribution in natural polysaccharides.
Graphical abstract
... While, the amino acids present to a lesser extent are glycine, histidine, leucine, phenylalanine and threonine (Anderson, Howlett, & McNab, 1985;Osman, Williams, Menzies, & Phillips, 1993). ...
The number of studies on the surface composition of microparticles obtained by spray drying has increased due to the interest in understanding the relationship between the characteristics of these microparticles and the oxidation stability of encapsulated bioactive compounds. The aim of this study was to evaluate the effect of emulsification techniques on the distribution of components on the surface, microstructure, and physicochemical properties of encapsulated β-carotene microparticles obtained by spray drying. Emulsions created by microfluidization and observed by XPS showed a greater presence (11.35–16.82%) of hydrophilic amino acids (histidine, glycine, serine, threonine) on the surface. Emulsions obtained by rotor/stator system exhibited low encapsulation efficiency (9.1–46.0%), and the microparticles presented a high number of surface irregularities (shrinkage and dents) compared to the microfluidization samples. In contrast, emulsions obtained by microfluidization showed shorter wetting (12.37–14.47 min) and solubility times (25.66–30.22 min), attributed to the percentage of protein on the surface of microparticles. The characteristics of the microparticles provided by the microfluidizer could help in the design of fast-hydration and dispersion powder products by spray drying.
... This provides the arabinogalactan with its anionic nature. Arabic gum is known to contain about 15-16% of glucuronic acid units (Osman, Williams, Menzies, & Phillips, 1993). ...
The ability of pea protein isolates (PPI) to form complex coacervates with tragacanth gum was investigated. The coacervate formation was structurally compared to three other PPI-polysaccharide interaction models: arabic gum and sodium alginate (known to form coacervates with PPI) and tara gum, a galactomannan. The effects of the pH and protein/polysaccharide ratio were mainly investigated using turbidity and zeta potential measurements. Regarding the pH of soluble complex formation, the pH of complex coacervates increased with the increase in protein-anionic polysaccharide mixture ratio. SEM images revealed the ability of the spray-drying process to form spherical particles of pea protein-polysaccharide complexes. The specificity of the microparticle surface was protein-dependent. FTIR analyses of coacervates showed the electrostatic interaction between the PPI and the polysaccharides. The results showed that tragacanth gum could be used as an alternative to gum arabic to form complex coacervates with PPI based on zeta potential measurements and coacervation yield studies.
... Gum arabic or acacia gum is a highly branched water soluble heteropolysaccharide obtained from the Acacia Senegal and Acacia seyal trees, belonging to leguminosae family. It is composed of Galactopyranose, L-arabinose, L-rhamnose, D-glucuronic and some proteins as well (Osman et al. 1993). The backbone is composed of 1, 3-linked β-D-galactopyranosyl units, along with side chain is composed of two to five 1, 3-linked β-D-galactopyranosyl units joined to the main chain by 1, 6-linkages ( Figure 4). ...
There is an emerging interest in the field of natural polymers in recent years due to increasing concerns about sustainability and various environmental issues. In this chapter, we highlighted various types of natural polymers (chitosan, chitin, alginate, cellulose, dextran, xylan, etc.) derived from various sources, their structure, occurrence and functions along with their broadly enlarging applications.
... Gum Arabic is a naturally-occurring non-starch complex carbohydrate that is made up of the hardened sap of acacia trees. Its makeup consists of rhamnose, galactose, glucuronic acid, and arabinose (Butler & Cretcher, 1929;Osman, Williams, Menzies, & Phillips, 1993). The purpose of this experiment is to determine whether Bifidobacterium strains isolated from the fecal samples of marmosets are able to ferment gum Arabic or its main component, arabinose. ...
Bifidobacterium is a genus of anaerobic bacteria that are commonly found to inhabit the gastrointestinal tract of many members of the animal kingdom. These microorganisms are adapted to obtain their carbon from the breakdown of complex carbohydrates. Marmosets, a mammal whose gut microbiome is inhabited by high levels of Bifidobacteria, consume gum Arabic as a major part of their diet. The purpose of this experiment is to determine whether Bifidobacterium strains isolated from the guts of marmosets are able to degrade and ferment this complex carbohydrate or one of its main constituents, arabinose. This was accomplished by inoculating isolates of Bifidobacterium species into tubes containing basal MRS medium supplemented with gum Arabic or arabinose and monitoring pH (color change) over time. Each of the 12 marmoset-derived isolates were tested in liquid media containing either 5% arabinose, 3% gum Arabic, or 1% gum Arabic. A positive phenotype indicating fermentation of the substrate was visualized by a shift in the media’s color from purple to yellow. The fermentative capabilities of the marmoset strains were then compared to 13 other Bifidobacterium strains that were isolated from other mammals such as rats, pigs, and humans. Two strains from each group expressed a negative phenotype for arabinose, while all other strains were positive. In the marmoset group, 6 of the strains expressed positive phenotypes for the 1% gum and 8 were positive for the 3% concentration. The group of strains from non-marmoset origins sported 5 positive phenotypes for the 1% concentration of gum Arabic, while 6 strains tested positive for the 3% concentration.
... The chemical composition of GA varies slightly depending on its origin, climate, harvest season, tree age, and processing conditions, such as spray dying [20][21][22][23]. Many studies have shown some differences between the chemical composition of the GA from Acacia senegal and Acacia seyal [24][25][26], the most recent study was conducted by Lopez-Torrez et al. [29]. Both Acacia Gums contained the same amino acids with a higher content of protein in A. senegal (2.7%) than in A. seyal (1.0%) (Table 1). ...
... The GA is also known as gum acacia which is harvested from Acacia senegal L. trees and 85% of it comes from Sudan. The chemical composition of which is n-galactopyranosyl, L-rhamnopyranosyl, Larabinopyranosyl and D-glucopyranosyluronic acid units with calcium, magnesium and potassium ions [19]. All these findings support using GA as an edible coating of guava fruits. ...
Guava (Psidium guajava L.) is a lovely tropical and subtropical fruit that originates in Mexico, Central America, and then taken
to other distant and near parts around the world. In Sudan this popular fruit is produced in orchards and household and is so
profitable but yet attacked by a lot of fruit fly species of the Genera Ceratitis and Bactrocera and the result is a loss of more
than 70%. This research aimed at evaluating the effect of Gum Arabic coating (GAC) in extending the shelf life of guava fruit
and disinfesting it from these notorious pests. Guava fruits from Kadaro orchards, Khartoum North, were tested using seven
concentrations of Gum Arabic solutions. The results reflect that 1: 4 (25%) and 1: 8 (12.5%) (GA: water) concentrations attained
56 and 40% disinfestation, respectively whereas the other lower concentrations effected corresponding results in a range from
20–08%. The reduction in maggots per test fruit reached upto 188% as compared to the control. The highest concentrations (1:
4 and 1: 8) effected a sustainability of 52% in fruit firmness (FF) with an average of medium (3) FF compared to soft FF (4) in
the control. The corresponding results in other lower concentrations (1: 16; 1: 32; 1: 64; 1: 72 and 1: 96) were 36, 24, 24, 20 and
16%, respectively. In addition to an average FF of 4 (soft) for all these concentrations and 5 (very soft) for all the corresponding
controls. Nevertheless, the sustainability of fruit color (FC) effected by the test concentrations was 52, 44, 24, 22, 24, 20, and
24%, respectively. Regarding these results, the two highest test concentrations effected a sizeable disinfestation and control of
fruit flies and a good extension of shelf life of guava in Khartoum State. These findings support using this treatment as an
effective IPM tool to extend guava fruit shelf life and upgrading its postharvest quality.
... The GA is also known as gum acacia which is harvested from Acacia senegal L. trees and 85% of it comes from Sudan. The chemical composition of which is n-galactopyranosyl, L-rhamnopyranosyl, Larabinopyranosyl and D-glucopyranosyluronic acid units with calcium, magnesium and potassium ions [19]. All these findings support using GA as an edible coating of guava fruits. ...
Guava (PsidiumguajavaL.) is a lovely tropical and subtropical fruit thatoriginates in Mexico, Central America,and then taken to other distant and near parts around the world. In Sudan this popular fruit is producedin orchards and household andis so profitable but yet attacked by a lot of fruit fly species of the GeneraCeratitisand Bactroceraand the result is a loss of more than 70%. This research aimed at evaluating the effect of Gum Arabic coating (GAC) in extendingthe shelf life of guava fruit and disinfesting it from these notorious pests. Guava fruits from Kadaro orchards, Khartoum North, were tested using seven concentrations of Gum Arabic solutions. The results reflect that 1: 4 (25%) and 1: 8 (12.5%) (GA: water) concentrations attained 56 and 40% disinfestation, respectively whereas the other lower concentrations effected corresponding results in a range from 20–08%. The reduction in maggots per test fruit reached upto 188%as compared to the control.The highest concentrations (1: 4 and1: 8) effected a sustainability of 52%in fruit firmness (FF) with an average of medium(3) FFcompared to soft FF (4) in the control. The corresponding results in other lower concentrations (1: 16; 1: 32; 1: 64; 1: 72 and1: 96) were 36, 24, 24, 20 and 16%, respectively. In addition to an average FF of 4 (soft) for all these concentrations and 5 (very soft) for all the corresponding controls.Nevertheless,the sustainability of fruit color (FC) effected by the test concentrations was 52, 44, 24, 22, 24, 20,and 24%, respectively. Regarding these results,the two highest test concentrations effected a sizeable disinfestation and control of fruit flies and a good extension of shelf life of guava in Khartoum State. These findings support using this treatment as an effective IPM tool to extend guava fruit shelf life and upgrading its postharvest quality. Keywords:Guava, Fruit flies, Shelf life, Fruit firmness, Color and quality
Guava (Psidium guajava L.) Fruit Coating with Gum – Arabic for Quality and Fruit Fly Control. Available from: https://www.researchgate.net/publication/324969919_Guava_Psidium_guajava_L_Fruit_Coating_with_Gum_-_Arabic_for_Quality_and_Fruit_Fly_Control [accessed May 25 2018].
... Rather, A. seyal gum contains a lower extent of nitrogen, and specific rotations are also completely different. The evaluation of the last parameters may plainly detect the distinction between the two species (Osman et al., 1993). ...
An experiment to determine the effect of gum Arabic (GA) concentrations (0.5, 1.0, and 1.5%) on organoleptic and physicochemical properties of yogurt was conducted using fresh cow's milk with 3% starter culture. The clotting time of the milk was determined by visual observation at 45°C using a constant temperature incubator. Curd formation was observed by rotating the container. Results showed that organoleptic properties of the yogurt increased as the percentage of GA advanced in all tested samples. Yogurt produced using (1.5%) GA had acceptable characteristics (appearance 16.9, color 17.3, body and texture 16.9, flavor 17.4, and taste 16.8). Increasing the amount of GA concentrations in the milk significantly decreased the clotting time in all treatments. Yogurt produced with low concentrations of gum had longer coagulation time (100-110 min) than that produced with high concentration (90 min). The curd obtained with high concentrations of GA was found to be firmer than that obtained using low concentrations. A GA concentration of 1.5% satisfied all the previous characteristics in the manufacture of yogurt, being scored by 85.3% of the respondents.
... The GA is also known as gum acacia which is harvested from Acacia senegal L. trees and 85% of it comes from Sudan. The chemical composition of which is n-galactopyranosyl, L-rhamnopyranosyl, L- arabinopyranosyl and D-glucopyranosyluronic acid units with calcium, magnesium and potassium ions [19]. All these findings support using GA as an edible coating of guava fruits. ...
Guava (Psidium guajava L.) is a lovely tropical and subtropical fruit that originates in Mexico, Central America, and then taken to other distant and near parts around the world. In Sudan this popular fruit is produced in orchards and household and is so profitable but yet attacked by a lot of fruit fly species of the Genera Ceratitis and Bactrocera and the result is a loss of more than 70%. This research aimed at evaluating the effect of Gum Arabic coating (GAC) in extending the shelf life of guava fruit and disinfesting it from these notorious pests. Guava fruits from Kadaro orchards, Khartoum North, were tested using seven concentrations of Gum Arabic solutions. The results reflect that 1: 4 (25%) and 1: 8 (12.5%) (GA: water) concentrations attained 56 and 40% disinfestation, respectively whereas the other lower concentrations effected corresponding results in a range from 20 – 08%. The reduction in maggots per test fruit reached upto 188% as compared to the control. The highest concentrations (1: 4 & 1: 8) effected a sustainability of 52% in fruit firmness (FF) with an average of medium (3) FF compared to soft FF (4) in the control. The corresponding results in other lower concentrations (1: 16; 1: 32; 1: 64; 1: 72 & 1: 96) were 36, 24, 24, 20 and 16%, respectively. In addition to an average FF of 4 (soft) for all these concentrations and 5 (very soft) for all the corresponding controls. Nevertheless, the sustainability of fruit color (FC) effected by the test concentrations was 52, 44, 24, 22, 24, 20, and 24%, respectively. Regarding these results, the two highest test concentrations effected a sizeable disinfestation and control of fruit flies and a good extension of shelf life of guava in Khartoum State. These findings support using this treatment as an effective IPM tool to extend guava fruit shelf life and upgrading its postharvest quality.
... Gum Arabic is an anionic complex of arabinose-galactose, with the main chain very branched in the side by chains of galactose, arabinose, rhamnose and glucuronic acid. It is negatively charged in almost the entire pH range, except at very low pH, in which the dissociation of the carboxyl group is removed (Osman, Williams, Menzies, & Phillips, 1993). ...
Palm oil is a carotenoid‐rich natural compound, whose microencapsulation by complex coacervation may protect it against adverse conditions, allowing applications in food formulations for nutritional enrichment and natural pigmentation. Besides, since the coacervates are insoluble in acid pH of stomach, this undigested lipid is delivered slowly in the intestinal tract, which can help treatment of metabolic disturbs. Accordingly, this study intended to optimize palm oil microencapsulation by complex coacervation using gelatin and gum Arabic as wall materials. For this purpose, the effects of wall material concentration (WM) (2.5, 5.0, and 7.5% w/v), gelatin:gum Arabic ratio (G:GA) (1:2; 1:1; 2:1), and core:wall material ratio (C:WM) (75, 100, and 125%) on the encapsulation efficiency, particle morphology, and size distribution of microcapsules were investigated. Microencapsulation assays followed a factorial central design and, after coacervation, the microcapsules were freeze‐dried. The highest values of encapsulation efficiency were obtained using G:GA = 1:1 or 2:1 with C:WM = 100%, whereas the WM concentration could vary from 2.5 to 7.5%. High concentrations of WM (7.5%) and G:GA = 2:1 hampered the formation of spherical or oval microcapsules. Microcapsules showed average diameter ( D [4.3] ) between 97 and 690 µm, with increasing concentration of WM and higher C:WM ratio contributing to formation of larger microcapsules. The G:GA ratio showed the highest influence on the particle size, with the 1:2 ratio resulting in smaller microcapsules.
Practical applications
Palm oil is a significant source of antioxidants and other phytonutrients, and its microencapsulation may protect these bioactive compounds, enabling its use to nutritional enrichment of dry food formulations, at the same time as functioning as a natural pigment given the intense reddish‐orange color of the oil. In addition, the microcapsules may slow down palm oil release in the gastrointestinal tract, since the coacervates are insoluble in acid pH of stomach, allowing this nutrient to achieve the ileum before being digested and help treatment of metabolic disturbs. Accordingly, microencapsulation of palm oil can be of great interest for food and pharmaceutical industries to develop controlled‐delivery systems to encapsulate and slow down digestion of lipids, inducing modulation of satiety response.
... The chemical composition of GA varies slightly depending on its origin, climate, harvest season, tree age, and processing conditions, such as spray dying [20][21][22][23]. Many studies have shown some differences between the chemical composition of the GA from Acacia senegal and Acacia seyal [24][25][26], the most recent study was conducted by Lopez-Torrez et al. [29]. Both Acacia Gums contained the same amino acids with a higher content of protein in A. senegal (2.7%) than in A. seyal (1.0%) (Table 1). ...
Gum Arabic (GA) is a natural branched-chain multifunctional hydrocolloid with
a highly neutral or slightly acidic, arabino-galactan-protein complex containing
calcium, magnesium, and potassium. Gum Arabic is dried exudate obtained from
the stem and branches of Acacia trees manly Acacia senegal and Acacia seyal.
GAwas used by the Ancient Egyptians as an adhesive when wrapping mummies
and in mineral paints when making hieroglyphs since the second millennium BC.
In modern times, GA is used in foods, pharmaceutical, and many other industries.
In this chapter, we describe the structure, chemical, and physical properties of
Gum Arabic. In addition, biological properties include antioxidant properties of
Gum Arabic, an effect of GA on renal function, blood glucose concentration,
intestinal absorption, degradation of GA in the intestine, lipid metabolism, tooth
mineralization, and hepatic macrophages. Similarly, pharmaceutical, food, and
cosmetic properties of Gum Arabic are discussed.
... The GA is also known as gum acacia which is harvested from Acacia senegal L. trees and 85% of it comes from Sudan. The chemical composition of which is n-galactopyranosyl, L-rhamnopyranosyl, Larabinopyranosyl and D-glucopyranosyluronic acid units with calcium, magnesium and potassium ions [19]. All these findings support using GA as an edible coating of guava fruits. ...
... As we previously reported (2), hemagglutination of type B-erythrocytes by SHA was inhibited in the presence of plant-originated galactomannans, with guar gum > locust bean gum > gum arabic. Gum arabic is known to contain galactose, rhamnose and arabinose as major components (16). However, the precise substructure required to bind SHA remains to be determined. ...
Blood type B-specific Streptomyces S27S5 hemagglutinin (SHA) was discovered and characterized in the 1970s. Although strain 27S5 has been lost, the purified SHA protein survived intact under frozen conditions and retained its activity. Using modern techniques, here we further characterized SHA. Fourier-transform ion cyclotron resonance MS analysis determined SHA's average molecular mass as 13,314.67 Da. MS of digested SHA peptides, Streptomyces genomic database matching, and N-terminal sequencing solved the 131-residue amino acid sequence of SHA. We found that SHA is homologous to N-terminally truncated hypothetical proteins encoded by the genomes of S. lavendulae, S. sp. Mg1, and others. The gene of the closest homologue in S. lavendulae, a putative polysaccharide deacetylase (PDSL), encodes 68 additional N-terminal amino acids, and its C terminus perfectly matched the SHA sequence, except for a single A-to-E amino acid difference. We expressed recombinant SHA(PDSL-A108E) (rSHA) as an enzymatically cleavable fusion protein in E. coli, and glycan microarray analyses indicated that refolded rSHA exhibits the blood type B- and L-rhamnose-specific characteristics of authentic SHA, confirming that rSHA is essentially identical with SHA produced by S. sp. 27S5. We noted that SHA comprises three similar domains, representing 70% of the protein, and that these SHA domains partially overlap with annotated Clostridial hydrophobic with conserved W (ChW) domains. Furthermore, examination of GFP-tagged SHA revealed binding to microbial surfaces. rSHA may be useful both for studying the role of SHA/ChW domains in carbohydrate binding and for developing novel diagnostics and therapeutics for L-rhamnose-containing microorganisms.
... 3 Therefore, two common polysaccharides; arabic gum and carrageenan which are widely used in as approved main ingredient or additives in food industries due to their unique properties has been selected in this study. 4,5 Arabic gum is an exudate tree gum that functioned as emulsifier agent in medicines or drink syrup because it is extremely soluble in water up to 50% concentration. 6 Meanwhile, carrageenan is a seaweed extract that can be diluted in DI water to produce a very viscous solution at low concentration. ...
p>The main objective of this work is to develop film and study the thermal characteristics of polysaccharides films at various concentration of carrageenan in the mixture by calculating activation energy of polysaccharides films. There were four (4) film samples of two polysaccharides combination; arabic gum (AG) and carrageenan (C) with different formulations; sample A, sample B, sample C and sample D prepared. Sample A film is the control sample that contained only arabic gum and distilled water (DI) with 40% weight arabic gum per volume DI water (w/v%). Meanwhile for sample B and C were prepared with concentration 40 w/v% of Arabic gum and two differents of carrageenan concentrations; 1 w/v% and 10 w/v% respectively. Polyethylene glycol 400 (PEG 400) as a plasticiser was added into sample D film. The sample films were thermally characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under nitrogen atmosphere. The major thermal transitions as well as, activation energies of the major decomposition stages were determined. Sample A and B films exhibited the highest (112.43 kJ/mol) and the lowest (102.89 kJ/mol) activation energy of thermal decomposition, respectively. The activation energies were lower at larger amounts of sulfate groups from carrageenan on the degradation reactions. The DSC trend for all samples shows two (2) major intense peaks recorded in the DSC thermograms; an endothermic transition at temperature around 100°C and followed by an exothermic transition at temperature around 300°C. The endothermic transition is due to the heat absorption for dehydration of water, H2O and the decomposition of samples process. Meanwhile, the exothermic transition is caused by the formation of H2O, CO and CH4 in polysaccharide film from dehydration, depolymerisation and decomposition at the high-temperature stages.
Chemical Engineering Research Bulletin 19(2017) 80-86</p
... Of the various potential resources, the plant kingdom owing to the great diversity of its species has often been considered as one of the most important choices to meet this goal. A large number of natural gums have been studied over the last decades (Balaghi, Mohammadifar, & Zargaraan, 2010;Dakia, Blecker, Robert, Wathelet, & Paquot, 2008;Dhami et al., 1995;Funami et al., 2009;Kang, Guo, Wang, Phillips, & Cui, 2015;Osman et al., 1995;Rinaudo, 2006;Thrimawithana, Young, Dunstan, & Alany, 2010) but only a few have successfully been commercialized and launched on to the market (Katzbauer, 1998;Osman, Williams, Menzies, & Phillips, 1993;Ramaswamy & Basak, 1992). ...
Persian gum is an exudate polysaccharide from the trunk and branches of wild almond tree which has recently attracted the attention of many researchers owing to its unique properties and the diverse possible applications it may find in the food industry. This article provides a comprehensive review on the physicochemical, structural and functional characteristics (e.g., emulsifying properties) of the gum and introduces a number of attempts made with the view to use it for improving the flow behavior, texture or shelf life stability of food products.
... GA displayed a low molar mass (3.4 Â 10 5 g mol Àl ), proteinpoor component (population 1) and a high molar mass (1.9 Â 10 6g mol À1 ), protein-rich component (population2) [19]. In earlier studies, population 1, the major component in GA, is referred to as arabinogalactan (AG) [20,21]. Fig. 1 shows the molecular structure of arabinogalactan (AG) [22]. ...
Purpose
This paper aims to investigate the influence of temperature (25 to 65 C°) on the adsorption and the inhibition efficiency of Gum Arabic for the corrosion of API 5L X42 pipeline steel in 1M HCl.
Design/methodology/approach
Inhibition behaviour on steel in HCl has been studied in relation to the concentration of the inhibitor as well as the temperature using potentiodynamic polarization curves and electrochemical impedance spectroscopy. Thermodynamic parameters of adsorption were calculated from the viewpoint of adsorption theory.
Findings
The results show that, at a temperature range from 25 to 65 C°, Gum Arabic was good inhibitor for API 5L X42 pipeline steel and its inhibition efficiency was significantly stable. The maximum inhibition efficiency (93 %) is obtained at 4 g l-1. In absence and presence of GA, there is almost no change in the corrosion mechanism occurs regardless of the temperature. The adsorption of (GA) on steel surface is an exothermic process. The adsorption of (GA) involves physical adsorption.
Practical implications
The use of Gum Arabic as an eco-friendly corrosion inhibitor is practical for carbon steel in hydrochloric acid.
Originality/value
The stability of inhibition efficiency of Gum Arabic at a temperature range from 25 to 65 C° could find possible applications in acid pickling, industrial acid cleaning and acid descaling.
... We assume that the following considerable reasons could be behind the better cyclic performance of GA/H 3 PO 4 -based solid-state supercapacitor compare to that PVA/H 3 PO 4 -based solidstate supercapacitor. The GA is a fairly complex chemical combination of branched polymers and oligomers containing arabinose, galactose, rhamnose, and uronic acids as monosaccharide components that can also be associated with some proteins [22], hence, the presence of substantial functional groups which can make an efficient contact with solid phase of electrode surface. The good contact between the interface of electrolyte and electrode may provide comparatively higher wettability to the electrode surface, increasing the ion adsorbing ability and accelerating electron transfer to the surface of electrode [17,18]. ...
The development of innovative gel electrolyte is nowadays considered one of the most important features for the realization of high-safety and high-performance energy storage devices. Consequently, in the past few years, much effort have been dedicated to prepare new gel polymer electrolytes, unfortunately, they suffer from poor wettability with electrode surface which retard them to achieve high ion accessibility. Here, we propose a novel gel-like electrolyte which is prepared by exploiting the emulsifying property of low cost and environmentally safe gum Arabic (GA) as the polymer matrix and ortho-phosphoric acid (H3PO4) as the supporting electrolyte. This prepared gel electrolyte (GA/H3PO4) demonstrates excellent supercapacitive performance in the counterpart of conventional gel electrolyte of polyvinyl alcohol (PVA)/H3PO4 in all-solid-state supercapacitor. Besides the electrolytic performance, as prepared gel also exhibited the self-healing feature, no decay in capacitance was observed upon mechanically separation and restacking of both electrodes of the solid-state assembly. The prepared GA/H3PO4 electrolyte is also capable of maintaining its capacitance over 5000 repeating charge/discharge cycles.
... It is suggested that the high-molecular-weight fraction of the gum consists of large carbohydrate blocks with a molecular mass of approximately 2.5 · 10 5 Da attached individually to a polypeptide chain. GA is obtained from the stems and branches of Acacia Senegal and Acacia seyal, and being a branched polysaccharide, it exhibits unique structural, physical and chemical properties [84][85][86][87]. Consequently, it is widely used in food and pharmaceutical applications [88][89][90]. ...
The recent advances and potential applications of nanoparticles and nanofibres for energy, water, food, biotechnology, the environment, and medicine have immensely conversed. The present review describes a 'green' method for the synthesis and stabilization of nanoparticles and 'green electrospinning' both using tree gums (arabic, tragacanth, karaya and kondagogu). Furthermore, this review focuses on the impending applications of both gum stabilized nanoparticles and functionalized membranes in remediation of toxic metals, radioactive effluents, and the adsorptive removal of nanoparticulates from aqueous environments as well as from industrial effluents. Besides, the antibacterial properties of gum derivatives, gum stabilized nanoparticles, and functionalized electrospun nanofibrous membranes will also be highlighted. The functionalities of nanofibrous membranes that can be enhanced by various plasma treatments (oxygen and methane, respectively) will also be emphasized.
Tea tree oil (TTO) is widely known essential oil extracted from Melaleuca alternifolia leaves naturally having antimicrobial and antibacterial activities. Due to its highly volatile nature it rapidly evaporates causing loss of efficiency and shorten the effects. Microencapsulation technique was incorporated to ensure the core material is being protected from the immediate contact with the environment and offers controlled release. In this study, microencapsulation of Tea Tree Oil was done by employing complex coacervation technique using Chitosan - Gum acacia system as the coating material and utilized tannic acid as the crosslinking agent. All the materials used in this process are from natural sources which are safe for the human and the environment. In designing the operating process condition for TTO encapsulation, we found that wall ratio of 2:5 and 3.6 pH gave the best yield along with better efficiency. The proposed method studied the surface morphology of the microcapsules with an efficiency and yield of 84.50% and 69.9 % respectively.
The aim of this research is the evaluation of inhibitory efficiency of Gum Arabic (GA) against the corrosion of API5L X60 pipeline steel in H2SO4 (0.5M) media, using mass loss measurement and electrochemical methods. The results show that inhibition efficiency increases with inhibitor concentration to attain 83% at 4 g/L of GA. Polarization curves reveal that GA acts as a mixed-type inhibitor in sulfuric acid. The adsorption of GA on pipeline API 5L X60 steel surface obeyed the Langmuir adsorption isotherm. Gibbs free energy of adsorption indicated that the adsorption process is spontaneous and the molecules adsorbed on the metal surface by the process of physical adsorption.
Gold nanoparticles (GNP) are noble metal nanocarriers that have been recently researched upon for pharmaceutical applications, imaging, and diagnosis. These metallic nanocarriers are easy to synthesize using chemical reduction techniques as their surface can be easily modified. Also, the properties of GNP are significantly affected by its size and shape which mandates its stabilization using suitable techniques of surface modification. Over the past decade, research has focused on surface modification of GNP and its stabilization using polymers, polysaccharides, proteins, dendrimers, and phase-stabilizers like gel phase or ionic liquid phase. The use of GNP for pharmaceutical applications requires its surface modification using biocompatible and inert surface modifiers. The stabilizers used, interact with the surface of GNP to provide either electrostatic stabilization or steric stabilization. This review extensively discusses the surface modification techniques for GNP and the related molecular level interactions involved in the same. The influence of various factors like the concentration of stabilizers used their characteristics like chain length and thickness, pH of the surrounding media, etc., on the surface of GNP and resulting to stability have been discussed in detail. Further, this review highlights the recent applications of surface-modified GNP in the management of tumor microenvironment and cancer therapy.
In this review, the focus of discussion is the polysaccharide fraction of cashew gum (CG), an exudate of Anacardium occidentale L., a plant typical of hot and humid tropical climates commonly found in northeastern Brazil and from which cashew nuts are extensively commercialized. CG purification, biological activity, and physical–chemical properties are explored in this work, in addition to applications of this biopolymer as a component of biomaterials used to either support, enhance, or replace damaged tissues or improve biological function. Evidence of its successful use to produce a range of biomaterials, from particles to gels and films, and to improve properties of already existing formulations are provided, supporting its versatility in this field of application.
Gum arabic (GA), an anionic polysaccharide, is very successfully employed as a carrier, because of its unique physicochemical and biological characteristics, such as its charge-based character, biocompatibility, and biodegradability. In the present chapter, first, the safety, compositional properties, and chemical structure of GA are discussed, and then different methods for the fabrication of GA-based nanostructured systems with an overview of the related research are summarized. The chapter also discusses the potential of GA-based nanostructured systems in food and pharmaceutical applications.
Gum Arabic (GA) is a polysaccharide widely used in industry as an emulsifier and encapsulating agent. Nevertheless, its physicochemical properties can be largely improved. The objective of this study was then to modify its structure to improve its functionalities or to provide new ones. To do so, a heterogeneous catalysis process using a laccase and a phenolic compound, curcumin, in aqueous solution was performed. The laccase allowed the oxidation of curcumin, which was then able to be grafted onto the polymer. Therefore, this environmentally friendly process allowed the modification of GA with curcumin oxidation products (OXP) by creating ester bonds between GA and OXP. The molecular mass of GA was largely increased after functionalization. This product contained two fractions of approximately ∼1.165 × 10⁸ g.mol⁻¹ and ∼5.057 × 10⁶ g.mol⁻¹. All these modifications impacted greatly the polymer properties such as its thermal behaviour, with a significant decrease of its glass transition, its hydrophilicity and its hygroscopicity. They also brought antioxidant properties to the modified GA. Moreover, the modification led interestingly to the spontaneous formation of spherical monodisperse micrometric particles in water.
Context
Obesity-associated chronic metabolic disease is a leading contributor to mortality globally. Plants belonging to the genera Acacia are routinely used for the treatment of diverse metabolic diseases under different ethnomedicinal practices around the globe.
Objective
The current review centres around the pharmacological evidence of intestinal-level mechanisms for metabolic health benefits by Acacia spp.
Results
Acacia spp. increase the proportions of gut commensals (Bifidobacterium and Lactobacillus) and reduces the population of opportunistic pathobionts (Escherichia coli and Clostridium). Acacia gum that is rich in fibre, can also be a source of prebiotics to improve gut health. The intestinal-level anti-inflammatory activities of Acacia are likely to contribute to improvements in gut barrier function that would prevent gut-to-systemic endotoxin translocation and limit “low-grade” inflammation associated with metabolic diseases.
Conclusion
This comprehensive review for the first time has emphasised the intestinal-level benefits of Acacia spp. which could be instrumental in limiting the burden of metabolic disease.
Gold nanoparticle (AuNP)-based systems have been extensively investigated as diagnostic and therapeutic agents due to their tunable properties and easy surface functionalization. Upon cell uptake, AuNPs present an inherent cell impairment potential based on organelle and macromolecules damage, leading to cell death. Such cytotoxicity is concentration-dependent and completely undesirable, especially if unspecific. However, under non-cytotoxic concentrations, internalized AuNPs could potentially weaken cells and act as antitumor agents. Therefore, this study aimed to investigate the antitumor effect of ultrasmall AuNPs (~3 nm) stabilized by the anionic polysaccharide gum arabic (GA-AuNPs). Other than intrinsic cytotoxicity, the focus was downregulation of cancer hallmarks of aggressive tumors, using a highly metastatic model of melanoma. We first demonstrated that GA-AuNPs showed excellent stability under biological environment. Non-cytotoxic concentrations to seven different cell lines, including tumorigenic and non-tumorigenic cells, were determined by standard 2D in vitro assays. Gold concentrations ≤ 2.4 mg L 1 (16.5 nM AuNPs) were non-cytotoxic and therefore chosen for further analyses. Cells exposed to GA-AuNPs were uptaken by melanoma cells through endocytic processes. Next we described remarkable biological properties using non-cytotoxic concentrations of this nanomaterial. Invasion through an extracellular matrix barrier as well as 3D growth capacity (anchorage-independent colony formation and spheroids growth) were negatively affected by 2.4 mg L 1 GA-AuNPs. Additionally, exposed spheroids showed morphological changes, suggesting that GA-AuNPs could penetrate into the preformed tumor and affect its integrity. All together these results demonstrate that side effects, such as cytotoxicity, can be avoided by choosing the right concentration, nevertheless, preserving desirable effects such as modulation of key tumor cell malignancy features.
The most prevalent food intolerance is the celiac disease. Consequently the research of different ingredient that can provide a better variety of food product and with higher quality is increasing. In this work the use of brea gum (BG) as enhancer in the development of gluten-free bread was evaluated comparing the result with a more common gum as Arabic gum (AG) and with a control sample. The gums were purified and physic-chemical characterized (moisture, ash, protein, fat, carbohydrates). Gluten free samples with and without gums were analyzed by measuring the specific volume (SV) of bread, textural profile and sensory properties. The results showed that BG has more of three times of protein, respect of AG improving nutritional value of the product. Also, samples with BG show a significant statistical increase of SV of bread in any of the proportions studied (2–5% w/w) (p > 0.05) with respect to the control and AG samples. Both hydrocolloids produce a statistical significate improvement in the bread texture, reducing the hardness, the chewability and the gomosity. The sensory analysis performed in samples with 3.5% w/w of gums revealed statistically significant difference in manual texture, flavor and global preference with respect to the control. The BG used is of natural origin and abundant in several regions of America, especially in much of the Argentine territory. Its application in the improvement of gluten-free bread formulations constitutes an opportunity for the food market and in parallel, for the survival of the native forest and its communities.
This study was carried out to explore the synbiotic of supplemented Gum Arabic and Bifidobacterium longum BB536 for developing functional peanut milk. Peanut was roasted at 130°C for 20 min and soaked in water for 12 h, blended 5 min and filtered using a double layered cheese cloth to prepare the roasted peanut milk. Ten grams of two types of gums Arabic (Acacia senegal and Acacia seyal) were weighted, dissolved in 90 ml of distilled water and heated (60°C for 30 min). Peanut milk beverages were supplemented with Gum Arabic solutions (100ml/ 900ml) Acacia senegal, Acacia seyal and mixed (A.senegal and A. seyal) and then were inoculated with Bifidobacterium longum BB536. The inoculation was carried out under controlled conditions at 37 ºC. The initial pH of the peanut milk was adjusted to 6.7 before mixing with gum Arabic solutions. Total bacterial count, pH, titrable acidity, TSS, total sugars, moisture, and Bifidobacterium longum BB536 viable count in peanut milk beverage were determined. There was an increase in total viable count and titrable acidity, decrease in pH, TSS and total sugars for all treatments. The maximum counts were 5.36, 6.79, and 6.95 log CFU/ml in fermented peanut milk, fermented peanut milk supplemented with Acacia senegal gum, fermented peanut supplemented with Acacia seyal , fermented peanut milk supplemented with gum mix,respectively. The maximum counts were attained at 18 h fermentation in all fermented milks exept in peanut supplemented with Acacia seyal gum (6.3 log CFU/ml) was attained at 24 h fermentation. The high levels of strain BB 536 in all fermented milk exceeded the minimum numbers required to presence in probiotics functional foods which are at least 6.0 log CFU/ml except fermented peanut milk without gum (5.36 log CFU/ml). Therefore, fermentation of peanut milk with Bifidobacterium longum BB536 and Gums Arabic could exert prebiotication effect and make suitable carrier for development of functional peanut milk.
This work characterized the physicochemical properties of two carbohydrate fractions, ASP1 and ASP2, that were sequentially extracted using NaOH and then NaOH/H 2 O 2 from the pulp remained from the extraction of sugar beet pectin (SBP). It has been shown that ASP1 and ASP2 differed from SBP in terms of chemical and macromolecular features. The ability of the ASPs to stabilize oil-in-water emulsions containing 10% w/w oil was compared using SBP and gum arabic (GA) as reference emulsifiers. The volume weighted droplet size (d 4,3 value) decreased as the concentration of SBP, ASP1, ASP2 and GA, increased in series 1.25, 1.5, 1.5, and 9% w/w and after which it remained constant except for ASP2 where the d 4,3 increased at concentrations above 2.5%. At concentrations of 1.25, 1.5, 1.5, and 9% of SBP, ASP1, ASP2, and GA, critical d 4,3 values of 0.55, 0.52, 2.14 and 0.55 μm were obtained, and droplet size for ASP2 was about 4 times greater compared with the other polysaccharides. The effects of pH (2–5) and ionic strength (Na ⁺ or Ca ²⁺ , 0–100 mM) on the emulsifying activity at the critical concentration of the polysaccharide were studied. Emulsions stabilized by either ASP1 or 2 were unstable in the presence of Ca ²⁺ due to the occurrence of bridge flocculation between oil droplets. It is concluded that ASP1 and ASP2 possess relatively inferior emulsification properties and, thus, are potential emulsifiers for use in low-calcium systems.
Gum Arabic is a natural acacia tree exudate containing hyperbranched polysaccharides and proteins. Here, we perform a dual chromatographic separation together with small-angle X-ray and neutron scattering structural characterizations. We show that the different species present in Gum Arabic can not be easily classified in distinct families. They are rather build from various combinations of two building blocks that are evidenced by a mismatch between small-angle X-ray and neutron scattering. One block corresponds to hyperbranched polysaccharides, which we describe as three-dimensional multi-scale porous colloids possessing three length scales of 7, 2 and 0.7 nm. The other block corresponds to protein chains that organize as Gaussian chains in solution and are prone to aggregation. A large array of polysaccharide/protein conjugates was identified, which differs in size, hydrophobicity and amino-acid content. Still, their structure is always the juxtaposition of the two building blocks structures. Additionally, small-angle neutron scattering reveals that large-scale structures are ubiquitous in Gum Arabic solutions and originate from the self-association of both free and conjugated polypeptide chains. Despite its compositional complexity, Gum Arabic solutions thus possess a robust multi-scale structure that is mainly impacted by concentration and ionic repulsions.
Previously, we fully investigated the chemical and structural characteristics of two acacia gum samples. Now, the gums’ physical chemical properties were investigated using zeta potential, fluorescence spectroscopy, potentiometric titration, viscometry and SAXS, and correlated to the gums's structural and self-association particularities. Since acacia gums are widely used in many food products, our aim was to elucidate the origin of the Acacia mearnsii gum (GN) properties in comparison with a commercial Acacia gum (GA). Both gums are negatively charged polyelectrolytes, nevertheless, the uronic acids in GN are stronger in view of the pKa of the carboxyl groups are ∼10–25% lower than in GA. Also, the acid dissociation constant (pKa) for both gums, can be related to the gums aggregation behavior. The pKa variability is more pronounced at lower gum concentrations and an inflexion point is noted close to the critical adsorption concentration. GN presents a more pronounced self-association behavior and a higher intrinsic viscosity (0.23 dL g⁻¹ vs 0.13 dL g⁻¹), indicating a less compact structure. The SAXS scattering profile of GA revealed two size levels, consistent with a thin ellipsoid morphology with 2.0 nm (thickness) and 12.0 nm (radius). GN, though, presented just one broad bulge, suggesting a higher dispersity level. It was demonstrated that specific variations in the gums chemical structure reflect directly on their self-assembly feature which, in turn, plays an important role on the gums intrinsic physical chemistry properties, whatever the probed length scale.
Gum Arabic (GA) is a soluble fiber obtained from Acacia senegal and Acacia seyal trees grown in sub-Saharan Africa, particularly Sudan. It is one of the most important medicinal plants used in traditional, or alternative, medicine. The main purpose of writing this chapter is to view recent and updated information about GA, which is promising as a medicinal plant and has short- and long-term health potentiality that can be developed as future phytopharmaceuticals to manage and/or treat panoply of various diseases. Pharmacologically, GA has been confirmed to have several therapeutic actions, such as being hypoglycemic, antidiabetic, antioxidant, immunomodulatory, and antiulcer. GA is used by local communities to protect against hepatic, renal, and cardiac complications in diabetic and chronic renal failure patients. The studies on the effects of GA on lipid metabolism in experimental animals are also documented. Ingestion of GA can decrease plasma cholesterol concentrations both in human and animals.
This study aimed to know the key chemical compound influencing gummosis in petioles of intact growing culinary rhubarb (Rheum rhabarbarum L.) with special emphasis on its sugar composition. The application of methyl jasmonate (JA-Me, 0.5 and 1% in lanolin, w/w) in the middle of intact petiole of growing rhubarb substantially induced gummosis in the entire petioles, below and above the treatment, within several days. JA-Me at 0.5% in lanolin greatly stimulated ethylene production in intact petiole of growing rhubarb, on the 3rd day after JA-Me treatment, ethylene level being increased five times or more. However, an ethylene-releasing compound, ethephon (2-chloroethylphosphonic acid, 1 and 2% in lanolin, w/w) alone had no effect on gummosis. Analysis of gum polysaccharides by a gel permeation chromatography with a Tosho TSK-gel G5000PW gel permeation column revealed that almost all of rhubarb gum polysaccharides were eluted near the void in this gel chromatography system, suggesting that molecular mass of rhubarb gum polysaccharides are more than 500 kDa, while precise mass has not been decided in this study. Analysis of gum sugar composition after hydrolysis revealed that rhubarb gums is rich in galactose (ca. 30%), arabinose (ca. 20%), and galacturonic acid (15–20%), although other sugars also existed in small quantities. These results suggest that the key chemical compound of gummosis in petioles of rhubarb is jasmonates rather than ethylene, and gum polysaccharides consist of not only pectic arabinogalactans but also homogalacturonans.
The gum arabic (GA) exudates from Acacia senegal have a wide range of industrial applications in their natural as well as chemically-modified forms. Chemical copolymerization is one of the most effective method for modifying structure and properties of polysaccharides. Likewise, polyaniline (PANI) is an intrinsically conducting polymer and is one of the most extensively studied pH-responsive redox polymer. Though, for better technological biocompatibility such as in the field of biosensors, the inclusion of GA due to its ionic functionality is highly desirable as smart zwitterion biomaterials. In this chapter, one such effort has been put forth to discuss gum arabic-co-polyaniline (GA-co-PANI) a pH-responsive redox copolymer and its properties for biosensor applications. The use of different schematic presentations will make it easier to understand the copolymerization of PANI onto GA electrical conductance, redox behavior, IV characteristics, and acid-base sensitivity. Herein we also describe its conducting mechanism.
Separation of the wound exudate from Acacia senegal (L.) Willd., "gum arabic," on a preparative Superose-6 column gave two major fractions: a high molecular weight gum arabic glycoprotein (GAGP) containing about 90% carbohydrate and a lower molecular weight heterogenous gum arabic polysaccharide fraction. Hydrogen fluoride-deglycosylation of GAGP gave a large ( approximately 400 residue) hydroxyproline-rich polypeptide backbone (dGAGP). Alkaline hydrolysis of GAGP showed that most of the carbohydrate was attached to the polypeptide backbone as small ( approximately 30 residue) hydroxyproline (Hyp)-polysaccharide substituents. After partial acid hydrolysis of the Hyp-polysaccharide fraction we identified O-galactosylhydroxyproline as the glycopeptide linkage, identical with that of hydroxyproline-rich arabinogalactan-proteins (AGPs). However, unlike the acidic alanine-rich AGPs, GAGP is basic and notably deficient in alanine. Thus, while the GAGP polypeptide backbone more closely resembles that of the Hyp-rich cell wall protein extensin, the GAGP polysaccharide sidechains resemble AGPs. Possibly all three proteins comprise a phylogenetically related extensin superfamily of extended rod-like macromolecules. The "wattle-blossom" model for AGP and gum arabic predicts a few large polysaccharide substituents along the polypeptide backbone of a spheroidal macromolecule. On the contrary, our data imply a rodlike molecule with numerous small polysaccharide substituents (attached to 24% of the Hyp residues), regularly arranged along a highly periodic polypeptide backbone based, hypothetically, on a 10 to 12 residue repetitive peptide motif. Thus, a simple statistical model of the gum arabic glycoprotein predicts a repeating polysaccharide-peptide subunit of about 7 kilodaltons. The small polysaccharide substituents will maximize intramolecular hydrogen bonding if aligned along the long axis of the molecule, forming in effect a twisted hairy rope. Electron micrographs of rotary shadowed GAGP molecules support that prediction and may also explain how such apparently large molecules can exit the cell by endwise reptation through the small pores of the primary cell wall.
Gum from Acacia senegal has been fractionated using hydrophobic affinity chromatography. Characterization, including identification of sugars and determination of protein and amino acid contents, has been undertaken for each fraction together with measurements of molecular mass and molecular mass distribution using laser light scattering and gel permeation chromatography. The results have indicated that the gum consists of three distinct components. Fraction 1. which represents 88.4% of the total, is an arabinogalactan with molecular mass 2.79 x 10(5) and is deficient in protein. Fraction 2, which represents 10.4% of the total. is an arabinogalactan-protein complex with a molecular mass of 1.45 x 10(6), containing similar to 50% of the total protein. It is envisaged that on average each molecule of fraction 2 consists of five carbohydrate blocks of molecular mass similar to 2.8 x 10(5) covalently linked through a chain of amino acid residues. Fraction 3 represents only 1.24% of the total gum but contains similar to 25% of the total protein and has been shown to consist of one or more glyeoproteins. Whereas the proteinaceous components of fractions 1 and 2 contain predominantly hydroxyproline and serine. this is not the case for fraction 3.
The chromatography of polysaccharides on resinous ion-exchangers has been reported by Steiner, Neukom, and Deuel (1958). Neukom et al. (1960) later reported the chromatography of a variety of wheat and sugar-beet polysaccharides on DEAEcellulose. Only "neutral" polysaccharides could be eluted at pH 6-8 by increasing buffer and salt concentrations; acid polysaccharides, e.g. pectic acid, were eluted by various strengths of alkali. Neutral polysaccharides could also be hromatographed at a somewhat alkaline pH by working with borate systems, which give charged complexes with many carbohydrates.
The gum polysaccharide of Acacia senegal, the main source of gum arabic, has been re-examined by means of two series of sequential Smith degradations, one starting with the whole polysaccharide, the other with a product from which all acid-labile side-chains had been removed by prior partial hydrolysis. Investigation, mainly by methylation analysis and estimation of molecular weight, of the products obtained at each stage of these two series of degradations, both of which ultimately yielded small galactans that appeared to be identical, has afforded evidence for the presence in the polysaccharide chain of uniform blocks of (1→3)-linked d-galactopyranosyl residues; these blocks are comparable in size to those postulated for many arabinogalactans of simpler structure. Some amplification of the structural model proposed for this polysaccharide by earlier workers is possible in the light of these new data.
Proteolysis of Acacia senegal gum by pronase leads to subunits of ~200 000 weight-average mol. wt. The origin of gum heterogeneity is discussed and considered to be due to a variable number of sub-units linked to a protein core.
Analytical data and 13C NMR spectra are presented for samples of gum from three Acacia senegal (L.) Wild. trees growing in Niger. The data show that the samples comply with the Revised (1990) Specification for gum arabic; the spectra reveale that the gums have, moreover, close structural similarities to Sudanese gum arabic. There is great scope in Niger to increase agroforestry activity based on expansion of its natural Acacia senegal population, but increased care will be necessary at the harvesting and marketing stages to ensure that gum from Acacia senegal is kept free from admixture with that from Combretum nigricans, Acacia seyal and Acacia sieberana, which are not permitted food additives, and which occur more extensively at present in Niger.
Antibodies directed against terminal carbohydrate units of gum arabic and gum mesquite were deteced in sera of rabbits immunized intramuscularly with solutions of the gums and Freund's complete adjuvant. The antibodies were isolated by affinity chromatography on adsorbents of AH-Sepharose 4B containing ligands of the appropriate gum. From the sera of animals immunized with gum arabic, two sets of anti-carbohydrate antibodies were isolated and these were shown to have specificity for different disaccharide units at the non-reducing ends of the gum molecule. From the sera of animals immunized with gum mesquite only one set of anti-carbohydrate antibodies with specificity for a terminal disaccharide unit was obtained. Isoelectric focusing coupled with agar diffusion of the purified antibodies showed that all of the sets of antibodies were composed of isomeric proteins with each isomer exhibiting antibody activity. The antibodies of a set are appropriately termed isoantibodies and it is likely that each isomer is synthesized by a different immunocyte of the host. Hapten inhibition studies with oligosaccharides isolated from the gums showed that gum arabic possesses two different immunodeterminants with the structure α-l-arabinofuranosyl-(1→4)-d-glucuronic acid and β-d-glucuronosyl-(1→6)-d-galactose while gum mesquite possessed only one determinant with the structure 4-methyl-β-d-glucuronosyl-(1→6)-d-galactose.
The exudate from Acacia Senegal (gum arabic) is a proteinaceous polysaccharide, the protein content ranging from ca. 1–5% to 3% for samples from different producing areas. The data presented for the proteinaceous components of eight bulk commercial gum arabic samples, and for eleven gum specimens secured from Acacia Senegal trees growing at various locations in the main Sahelian gum‐producing areas, show that their amino acid compositions vary considerably, particularly in respect of the three major components (hydroxyproline, serine and proline) although the proportions of other amino acids (e.g. alanine, cystine, isoleucine, methionine, threonine, tyrosine, valine) are remarkably constant. The data presented may be useful for extending the current specifications for identity and purity, at present based solely on polysaccharide parameters, for gum arabic (E414).
Analytical data for the sugar and amino acid compositions are presented for the gum exudates from Acacia gerrardii Benth. var. gerrardii and Acacia goetzii Harms subsp. goetzii Brenan, which have not been studied previously. Conversion factors have been calculated from the amino acid data to facilitate the conversion of Kjeldahl nitrogen values to protein contents; the factors are considerably higher than that assumed in earlier studies of Acacia spp. The analytical data substantiate previous chemotaxonomic conclusions that species in Bentham's sub-series Gummiferae (e.g. A. gerrardii) all have positive optical rotations, low viscosity, arabinose/galactose ratios greater than unity and low rhamnose contents. In contrast, species in Bentham's subseries Vulgares (e.g. A. goetzii) have negative optical rotations, are comparatively more acidic and more viscous, with arabinose/galactose ratios less than unity and higher proportions of rhamnose; such species can be regarded as being related to A. senegal, the source of commercial gum arabic. The data confirm previous evidence that hydroxyproline and serine are the major amino acids in the proteinaceous components of Acacia gums; such components are structurally and functionally important. Comment is made on the liabilities faced by gum importers.
Investigations involving fractional precipitation of A. senegal gum by sodium sulphate lead to a discussion on the type of heterogeneity exhibited by the gum. Molecular-sieve chromatography is used to estimate number-average molecular weights. Results obtained using this chromatographic technique on the degraded gum produced on autohydrolysis indicate that such mild conditions of hydrolysis are not always very selective as a means of degradation. The degraded gum is shown to have galactose residues as reducing end-groups. There is no evidence for labile, internal, arabinofuranosyl linkages in the whole gum. In addition, chromatographic evidence is obtained for the presence of 6-O-(4-O-methyl-β-D-glucopyranosyluronic acid)-D-galactose residues in A. senegal gum.
Fractionation of Acacia senegal gum has been carried out on Sephacryl gels S-400 and S-500. The shape and relative height of the chromatograms are sample dependent.Physicochemical data including circular dichroism and the weight-average molecular weights distribution show that about 70% of the material is composed of homogeneous polysaccharide chains with a very low nitrogen content. The remaining material is a combination of polysaccharide and nitrogen moieties (probably an arabinogalactan-protein complex).Our data are consistent with the new and simplified structural models proposed recently for this polysaccharide.
Native and disrupted granules were used to prepare and stabilise oil-in-water emulsions containing washed sunflower oil. Native granules were in an insoluble aggregated form, whereas, after addition of sodium chloride, granules were disrupted and their proteins and lipoproteins were liberated and solubilised. Native granules were adsorbed at the oil–water interface as complex particles without dissociation of their individual proteins and lipoproteins. This aggregated state allowed a greater surface coverage than the molecular state following upon granules disruption, because of the convective mass-transport occurring during homogenisation. However, in emulsions made by means of these aggregates, the droplet size was larger, and stabilisation against creaming and coalescence were less efficient than that of emulsions made with proteins and lipoproteins liberated from disrupted granules. The electrophoretic study of emulsion droplets revealed that, whatever the native or disrupted form, all major granules proteins were adsorbed at the oil–water interface. Results suggest that it is possible to realise emulsions with native granules but that such emulsions are less fine, less homogenous and less stable than emulsions realised with disrupted granules.
The gum fractions isolated from Acacia senegal gum using hydrophobic affinity chromatography have been further characterized by 1H- and 13C-NMR spectroscopy and by methylation analysis. Fractions 1 and 2 are essentially polysaccharides of similar sugar and uronic acid content, the units of which have now been found to be linked in the same manner, despite a difference in the proportion of associated protein (0.44 and 9.18% respectively). The glycoprotein fraction 3 (carbohydrate content 50–54%), comprising a minor but important part of the whole gum, is made up of monosaccharide units in the same relative proportions, which are linked in a similar manner to those found for the major, carbohydrate-rich components. A molecular model proposed earlier, wherein five carbohydrate blocks such as make up fraction 1 are joined to polypeptide to form fraction 2, gains support from the near identity of the carbohydrate moieties in these fractions. The carbohydrate in fraction 3 is of lower molecular weight than that of 1, and may be attached to any of the hydroxy-amino acids present in abundance.
Molecular size distribution of Acacia senegal gum on Sephacryl gel S-400 is compared before and after incubation with the proteolytic enzyme Pronase. The profile and elution volumes of chromatograms are greatly modified: a rather broad system of high molecular weight peaks near the exclusion volume is resolved into a single peak at lower molecular weight.Physicochemical data from isolated Pronase-treated samples tend to favour, for crude Acacia senegal gum, a structure where varying numbers of polysaccharide units of MW ca 2×105 are linked to a protein core. The effect of Pronase on Acacia mearnsii and Combretum nigricans gums was also investigated.Our results are discussed in relation to structural models proposed for these arabinogalactan-protein complexes.
In the light of advances in structural gum-chemistry, the analytical data available from earlier analytical and structural studies of gum arabic (Acacia Senegal Willd.), and of the gum exudates from Acacia laeta, A. campylacantha and A. seyal, have been re-interpreted. The structures originally suggested were based on random arbitrary assignments of substituent sugars without an attempt to establish regular structures. Modelling considerations and recalculations show that the data can also be interpreted in terms of more ordered structures. These are consistent with almost all of the available experimental data and give a much clearer insight into the nature and extent of the structural differences shown by the two Acacia gums of commercial importance. Acacia senegal (gum arabic, gum hashab) and Acacia seyal (gum talha).
Two sets of antibodies directed against different carbohydrate units of gum arabic were isolated from the sera of rabbits immunized intramuscularly with gum arabic and Freund's complete adjuvant. The isolation was effected by affinity chromatography on two columns attached in series and containing an absorbent of AH-Sepharose 4B with ligands of partially hydrolyzed gun arabic in the first column and an adsorbent of AH-Sepharose 4B with ligands of native gum arabic in the second column. The two populations of anti-gum arabic antibodies were obtained and have been designated as Set 1 and Set 2 on the basis of their mobilities on agar diffusion. The antibodies of Set 1 consisted of 4 isomeric antibodies and those of Set 2 consisted of 11 isomeric antibodies. Native gum arabic samples were oxidized with periodate or reduced with sodium borohydride and carbodiimide under standard conditions and the modified samples were totally inactive in the precipitin test. On the basis of methylation data and immunological results it was concluded that terminal disaccharide moieties of the gum having the structure beta-D-glucosyluronic acid-(1----6)-D-galactose and alpha-L-arabinofuranosyl-(1----4)-D-glucuronic acid were the immunodeterminant groups for Set 1 and Set 2 antibodies, respectively.
Antibodies directed at gum arabic have been induced in rabbits immunized with gum arabic in Freund's complete adjuvant. These antibodies have been isolated in pure form by affinity chromatography on AH-Sepharose 4B containing gum arabic ligands. Oxidation of the susceptable carbohydrate residues of gum arabic with periodate or reduction of the glucuronic acid moieties with carbodiimide and borohydride converted the polysaccharide to products which no longer yielded precipitin reactions with the antibodies. The antibodies are therefore anti-carbohydrate antibodies with specificity for certain carbohydrate units of the gum arabic. Results of chemical modification and inhibition experiments indicate that 4-alpha-L-arabinofuranosyl-D-glucuronic acid units of the polysaccharide are the major immunodeterminant groups.
Nitrogen conversion factors for gum arabic (Acacia senegal (L.) Willd.), gum tragacanth (Asiatic Astragalus spp.), gum karaya (Sterculia spp.), guar gum (Cyamopsis spp.), locust bean (carob) gum (Ceratonia spp.), tara gum (Caesalpinia spp.), and xanthan gum (Xanthomonas campestris) have been calculated from data for the amino acid compositions of their proteinaceous components. The factors derived differ from the arbitrary values (5.7 or 6.25) at present specified by international regulatory authorities for some emulsifiers, stabilizers and thickeners.
Convenient syntheses were developed to obtain on a multigram scale the novel taste enhancer N-(1-carboxyethyl)-6-(hydroxymethyl)pyridinium-3-ol 1, called alapyridaine, as a racemic mixture and as pure (+)-(S) and (-)-(R) enantiomers, respectively. 5-(Hydroxymethyl)-2-furaldehyde was used as key intermediate and was reacted with l-alanine under alkaline conditions to obtain racemic 1. Alternatively, reductive amination of 5-(hydroxymethyl)-2-furaldehyde with Raney-Ni/hydrogen and l- or d-alanine followed by mild oxidation led to (+)-(S)-1 and (-)-(R)-1, respectively. Racemization was promoted under alkaline and boiling conditions via a carbanion, the formation of which was facilitated by the electron-withdrawing effect of the iminium cation and the resonance-stabilizing capacity of the pyridinium moiety. Under these conditions, 1 was obtained in a 1:1 mixture of the phenol (1) and phenolate (1-H) forms as shown by X-ray diffraction. Racemic 1 formed monoclinic crystals of high molecular organization in which the phenol-type (RS)-1, the phenolate-type (RS)-1-H, sodium cations, and ethanol molecules are present. The crystal structure of [Na(1)(1-H).(C(2)H(6)O)] shows one-dimensional mu(2)-bridging-oxygen polymers stabilized by a three-dimensional network of ionic, hydrogen bond, and pi-stacking interactions with channels occupied by solvent molecules.
Adulteration of vegetable oil is of concern for both commercial and health reasons. Compositional based fingerprints can potentially reveal both the oil source and its possible adulteration. Here, electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) resolves and identifies literally thousands of distinct chemical components of commercial canola, olive, and soybean oils, without extraction or other wet chemical separation pretreatment. In negative-ion ESI FT-ICR MS, the acidic components of soybean oil are easily distinguished from those of canola and olive oil based on relative abundances of C(18) fatty acids, whereas olive oil differs from canola and soybean oil based on relative abundances of tocopherols. In positive-ion ESI FT-ICR MS, the three oils are readily distinguished according to the relative abundances of di- and triacylglycerols with various numbers of double bonds in the fatty acid chains. We demonstrate the detection of soybean oil as an adulterant of olive oil, based on relative abundances of members of each of several chemical families. We suggest that the detailed chemical compositions of vegetable oils can be used to characterize them and to detect and identify adulterants.
Specifications for gum arabic (Acacia senegal)
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Specifications for identity and purity of certain food additives; Food and Nutrition Paper 49; FAO: Rome Arabinogalactan-proteins: structure, biosynthesis and function
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Thevariationin composition and properties of gum nodules from Acacia seyal
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FAO. Specifications for identity and purity of certain food additives; Food and Nutrition Paper 34; FAO: Rome, 1986, pp 93-95.
For a discussion of the Journal's expectations for compound characterization, please read Compound Identification: A Journal of Agricultural and Food Chemistry Perspective
- Novel Compound Characterization
Novel Compound Characterization. For a discussion of the Journal's expectations for
compound characterization, please read " Compound Identification: A Journal of
Agricultural and Food Chemistry Perspective " by R. J. Molyneux and P. Schieberle. J.
DOI: 10.1021/jf070242j) It is essential that novel compounds, either synthetic or isolated from natural sources, be characterized rigorously and unequivocally. Supporting data normally include physical form, melting point (if solid
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Agric. Food Chem. 2007, 55, 4625–4629 (DOI: 10.1021/jf070242j). It is essential that novel
compounds, either synthetic or isolated from natural sources, be characterized rigorously and
unequivocally. Supporting data normally include physical form, melting point (if solid), UV/IR
spectra if appropriate, 1 H and 13 C NMR, mass spectrometric data, and optical rotation (when
compounds have chiral centers).
Analysis of Polyphenolic Antioxidants from the Fruits of Three Pouteria Species by Selected Ion Monitoring Liquid Chromatography–Mass Spectrometry
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Reporting liquid chromatography (HPLC) and HPLC/MS: " Analysis of Polyphenolic
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