Functional characteristics of gum arabic

Snowden, Martin J.; Phillips, Glyn O.; Williams, Pascale

doi:10.1016/s0268-005x(87)80017-6

Cited by 38 publications

(22 citation statements)

References 15 publications

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“…Since the adsorbed layer thickness is 61 nm in the presence of 0.5 M NaNO 3 this indicates that the molecules may adsorb end-on at the surface. Snowden previously reported that the adsorption capacity for Acacia senegal gum adsorbed onto polystyrene latex particles was 1 mg m À2 in water and that this increased to~5 mg m À2 for adsorption from electrolyte (Snowden, Phillips, & Williams, 1987). The increase in the amount adsorbed is explained by the fact that the electrolyte screens lateral electrostatic interactions between the gum molecules adsorbed at the surface allowing more to be accommodated.…”

Section: Adsorbed Layer Thicknessmentioning

confidence: 99%

Molecular characteristics, association and interfacial properties of gum Arabic harvested from both Acacia senegal and Acacia seyal

2016

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a b s t r a c tThe molecular composition of Acacia senegal and Acacia seyal gum exudate samples were studied using transmission electron microscopy. The molecules observed in both samples were found to have diameters of either~20 mm,~60 mm or~10 mm. These most likely represent the arabinogalactan (AG), arabinogalactan-protein (AGP) and glycoprotein (GP) molecules present in Acacia gum exudates. Micrographs obtained for gum solutions that had been left to stand for up to 5 days, indicated that molecular aggregation had occurred, this was particularly evident for the Acacia senegal sample. This aggregation process was attributed to intermolecular electrostatic interactions. The adsorbed layer thickness of the gums adsorbed onto polystyrene latex particles was determined using dynamic light scattering. For the Acacia senegal gum sample, it was found that the adsorbed layer thickness increased over time and after 14 days had a value of 61 nm. These findings are indicative of multilayer adsorption, through intermolecular electrostatic interaction. For the Acacia seyal gum sample the adsorbed layer thickness was only~3 nm and did not increase over time. Transmission electron microscopy revealed the presence of a distinct, thick adsorbed layer for the Acacia senegal gum and the presence of a much thinner, more diffuse layer for the Acacia seyal gum sample. Emulsification studies showed that the Acacia senegal gum was more effective at stabilising limonene oil-in-water emulsions than the Acacia seyal sample and that this was because markedly more Acacia senegal gum adsorbed at the oil-water interface compared to the Acacia seyal gum exudate.

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Section: Adsorbed Layer Thicknessmentioning

confidence: 99%

Molecular characteristics, association and interfacial properties of gum Arabic harvested from both Acacia senegal and Acacia seyal

2016

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“…This corresponds to zero time of hydrolysis. The pH was measured after 5,10,15,20,25,30,45,60,90,120,150,180 and 210 minutes of hydrolysis. The pH at the end of 5 minutes was found to be 1.60, and after 10 and 15 minutes, it was found to be 1.62 and 1.63 respectively.…”

Section: Acid Catalyzed Hydrolysismentioning

confidence: 99%

Fluorescence spectral studies of Gum Arabic: Multi-emission of Gum Arabic in aqueous solution

Dhenadhayalan

Mythily²,

Rajendran³

2014

Journal of Luminescence

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“…Obviously, the ability of AG to stabilize solid interfaces is the basis of ink and paint manufacturing [25][26][27]. AG was also used to stabilize latex nanoparticles as a model interface system with a surface coverage of about 0.5 to 5 mg/m 2 depending on the solvent conditions and initial AG concentration [28,29]. The surface coverage was found to be similar at liquid-liquid interfaces in oil-in-water O/W emulsions [4].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Hyperbranched Arabinogalactan-Proteins from Plant Exudate at the Solid–Liquid Interface

Davantès

Nigen

Sánchez

et al. 2019

Colloids and Interfaces

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Adsorption of hyperbranched arabinogalactan-proteins (AGPs) from two plant exudates, A. senegal and A. seyal, was thoroughly studied at the solid–liquid interface using quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR), and atomic force microscopy (AFM). Isotherms of the adsorption reveal that 3.3 fold more AGPs from A. seyal (500 ppm) are needed to cover the gold surface compared to A. senegal (150 ppm). The pH and salt concentration of the environment greatly affected the adsorption behavior of both gums, with the surface density ranging from 0.92 to 3.83 mg m−2 using SPR (i.e., “dry” mass) and from 1.16 to 19.07 mg m−2 using QCM-D (wet mass). Surprisingly, the mass adsorbed was the highest in conditions of strong electrostatic repulsions between the gold substrate and AGPs, i.e., pH 7.0, highlighting the contribution of other interactions involved in the adsorption process. Structural changes of AGPs induced by pH would result in swelling of the polysaccharide blocks and conformational changes of the polypeptide backbone, therefore increasing the protein accessibility and hydrophobic interactions and/or hydrogen bonds with the gold substrate.

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Functional characteristics of gum arabic

Cited by 38 publications

References 15 publications

Molecular characteristics, association and interfacial properties of gum Arabic harvested from both Acacia senegal and Acacia seyal

Molecular characteristics, association and interfacial properties of gum Arabic harvested from both Acacia senegal and Acacia seyal

Fluorescence spectral studies of Gum Arabic: Multi-emission of Gum Arabic in aqueous solution

Adsorption of Hyperbranched Arabinogalactan-Proteins from Plant Exudate at the Solid–Liquid Interface

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