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Glyn O Phillips - One of the best experts on this subject based on the ideXlab platform.
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interfacial and emulsifying properties of the electrostatic complex of β lactoglobulin fibril and gum arabic Acacia Seyal
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019Co-Authors: Zhiming Gao, Glyn O Phillips, Yapeng Fang, Katsuyoshi Nishinari, Ying Huang, Ke Zhang, Jixin YangAbstract:Formation, interfacial and emulsifying properties of the electrostatic complex of β-lactoglobulin fibril (BLGF) and gum Arabic Acacia Seyal (AS) were investigated. Necklace-like soluble complex could be formed at pH 3.5, and its charge and interfacial properties depended on the BLGF content. With appropriate amount of BLGF (< 9.09 wt.%), the formed complex possessed a good dispersibility and surface activity. When excessive BLGF (9.09∼50 wt.%) existed, surface charge of the complex was gradually neutralized and aggregation occurred. Homogeneous oil-in-water emulsions could be stabilized by the complex and the droplet size decreased with increasing BLGF content. Higher content of BLGF (9.09∼50 wt.%) was detrimental for emulsification due to the aggregation of complex, and the formed emulsion tended to flocculate. Compared with AS, the complex formed emulsions were much more stable against heating (90 ℃, 30 min) and salting (200 mM NaCl) environments, and the emulsions were stable during long-term storage (46 days). Proposed mechanisms for the adsorption of BLGF/AS complex at the oil-water interface. Pure AS (i) could adsorb at the oil-water interface but formed a loose film due to its poor surface activity and insufficient adsorption amount. With addition of a small amount of fibrils (ii), soluble electrostatic complexes are formed and they can be adsorbed at the interface to formed a dense viscoelastic film due to the surface activity of the BLGF. With a higher content of fibrils (iii), surface charge of the complex tended to be neutralized, causing the aggregation. Because the presence of protein fibrils, they could also adsorb at the oil-water interface to produce a viscoelastic film. However, with a bigger size and irregular shape, the aggregates were difficult to array at the interface as densely as the soluble complex.
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a novel emulsifier prepared from Acacia Seyal polysaccharide through maillard reaction with casein peptides
Food Hydrocolloids, 2017Co-Authors: Chuchu Hou, Glyn O Phillips, Yongmei Xia, Steve W CuiAbstract:Abstract A novel A. Seyal gum-based emulsifier was obtained with dramatically elevated emulsifying properties comparing to A. Seyal polysaccharide, by hydrophobically-modifying Acacia Seyal polysaccharide with casein hydrophobic peptide (CHP) through dry-state Maillard reaction. The formation of CHP- A. Seyal polysaccharide conjugate (SeyCHP) was confirmed with high performance size exclusion chromatography (HPSEC) and determination of graft of degree. The stability of the emulsion of canola oil in water stabilized with the conjugates was investigated. The results revealed that the emulsifying capacities of the conjugates were improved up to 46 times of that of Acacia Seyal polysaccharide, which is close to that of Acacia senegal gum; and the emulsion stability can be enhanced up to 21 times of that of Acacia Seyal polysaccharide. This indicates that covalent modification with hydrophobic peptide to hydrophilic polysaccharide may provide an efficient strategy to improve the emulsifying properties of hydrophilic polysaccharides.
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characterization and emulsifying properties of β lactoglobulin gum Acacia Seyal conjugates prepared via the maillard reaction
Food Chemistry, 2017Co-Authors: Hao Yang, Yapeng Fang, Katsuyoshi Nishinari, Glyn O PhillipsAbstract:Gum Acacia Seyal (ASY) is less valued than is gum Acacia Senegal, due to its poor emulsifying ability. The present study investigated the Maillard reaction between ASY and β-lactoglobulin (BLG) and its impact on the emulsifying properties of ASY. The reaction products of BLG/ASY mixture (r=1/4), prepared by dry-heating at 60°C and a relative humidity of 79%, as a function of incubation time, were characterized by SDS-PAGE, GPC-MALLS and DSC. The results showed that 12-24h of dry-heating under the given conditions was sufficient for conjugation, meanwhile avoiding the formation of deeply coloured and insoluble melanoidins. More than 64% of the protein was incorporated into ASY, resulting in a two-fold increase in arabinogalactan-protein (AGP) content and 3.5 times increase in weight-average molecular mass of ASY. The conjugation with BLG markedly improved the stability of ASY-stabilized emulsions and their resistance against severe conditions, such as low pH and high saline conditions.
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studies on Acacia gums part vii effect of exudates form and tree age on the characteristics of Acacia Seyal var Seyal and Acacia Seyal var fistula
Food Hydrocolloids, 2015Co-Authors: M Andresbrull, Glyn O Phillips, Ishragha G Abdalla, Jesus Cirre, James Edwards, Mohammed E Osman, Saphwan AlassafAbstract:Abstract Authenticated samples of Acacia Seyal var. Seyal and Acacia Seyal var. fistula have been investigated. Samples of each variety from young (5–7 years) and old trees (15–20 years) were collected during the same season from the Eldamazeen area of Sudan. For each variety, two types of gum exudates (seep and nodule form) were collected. The solubility, optical rotation, sugar composition, colour Gardner, viscosity, and molecular weights were measured. The rhamnose and uronic acid contents were higher in var. Seyal than var. fistula but the amount of arabinose is greatest in var. fistula . The galactose content is almost the same for all samples with the possible exception of var. Seyal with a higher content in older trees. The weight average molecular weight (M w ) for var. fistula is almost double that of var. Seyal and generally the proportion of the high molecular fraction increases with age. The average value for the M w of the arabinogalactan moiety (AG) is 6.2 × 10 5 and 9.3 × 10 5 g/mol for Seyal and fistula respectively. Tannin content is highest in seep (∼0.8 wt%), lowest in the nodule form (0.08 wt%) and is a contaminant resulting directly from contact of the gum exudate with the tree bark. Tannin content increases with the age of tree for Seyal var. Seyal but not for var. fistula samples. These results give a clear difference between these two Acacia gum varieties, both of which are currently regulatory approved as gum arabic for food use.
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the core carbohydrate structure of Acacia Seyal var Seyal gum arabic
Food Hydrocolloids, 2013Co-Authors: Steve W Cui, Shaoping Nie, Cathy Wang, Qi Wang, Mingyong Xie, Glyn O PhillipsAbstract:Abstract The structure of gum arabic ( Acacia Seyal ) has been studied using methylation analysis and 2D (COSY, TOCSY, HMQC and HMBC) NMR spectroscopy. Galacturonic acid (13.66%) is a major component not previously identified. The backbone is made up of 1,3-linked galactopyranosyl (Gal p ) residues substituted at O-2, O-6 or O-4 positions, which are terminated with mainly arabinofuranosyl (Ara f) , galacturonopyranosyl (Gal p A), rhamnopyranosyl (Rha p ), but occasionally with arabinopyranosyl (Ara p ), and glucuronopyranosyl (Glc p A) residues. There are long side chains of →3)-α- l -Ara f- (1→ and →2)-α- l -Ara f- (1→ linked to the backbone.
Naofumi Nakagawa - One of the best experts on this subject based on the ideXlab platform.
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foraging energetics in patas monkeys erythrocebus patas and tantalus monkeys cercopithecus aethiops tantalus implications for reproductive seasonality
American Journal of Primatology, 2000Co-Authors: Naofumi NakagawaAbstract:The patas monkeys (Erythrocebus patas) in Kala Maloue, Cameroon, have their birth season in the mid-dry season, whereas closely related, sympatric tantalus monkeys (Cercopithecus aethiops tantalus) have their birth season in the wet season. To evaluate the optimality of a species-specific birth season, I estimated the daily intake of available energy and gross protein, and energy expenditure for one individual of each sex of each species between respective birth and mating seasons. The monkeys obtained a larger amount of available energy and gross protein in the birth season than in the mating season. No significant seasonal differences in energy expenditure between the birth and mating season were found. Thus, the birth season appears to be timed to the season when the monkeys can obtain more surplus energy and protein. Interspecific differences in the optimality of birth season were attributed to widely exploitative foraging, supported by the patas’ high locomotive ability, which may enable them to obtain more energy from seeds of Acacia Seyal and gums of A. sieberiana, and more protein from grasshoppers and seeds of A. Seyal in the mid-dry season than the tantalus monkeys. A review of preceding studies suggests that the availability of seeds of Acacia fruiting during the dry season may exert the dominant influence on timing of birth not only in patas but also in savanna monkeys (Cercopithecus aethiops), which include the tantalus monkeys. Am. J. Primatol. 52:169–185, 2000. © 2000 Wiley-Liss, Inc.
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Foraging energetics in patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus): implications for reproductive seasonality.
American journal of primatology, 2000Co-Authors: Naofumi NakagawaAbstract:The patas monkeys (Erythrocebus patas) in Kala Maloue, Cameroon, have their birth season in the mid-dry season, whereas closely related, sympatric tantalus monkeys (Cercopithecus aethiops tantalus) have their birth season in the wet season. To evaluate the optimality of a species-specific birth season, I estimated the daily intake of available energy and gross protein, and energy expenditure for one individual of each sex of each species between respective birth and mating seasons. The monkeys obtained a larger amount of available energy and gross protein in the birth season than in the mating season. No significant seasonal differences in energy expenditure between the birth and mating season were found. Thus, the birth season appears to be timed to the season when the monkeys can obtain more surplus energy and protein. Interspecific differences in the optimality of birth season were attributed to widely exploitative foraging, supported by the patas' high locomotive ability, which may enable them to obtain more energy from seeds of Acacia Seyal and gums of A. sieberiana, and more protein from grasshoppers and seeds of A. Seyal in the mid-dry season than the tantalus monkeys. A review of preceding studies suggests that the availability of seeds of Acacia fruiting during the dry season may exert the dominant influence on timing of birth not only in patas but also in savanna monkeys (Cercopithecus aethiops), which include the tantalus monkeys.
Christian Sanchez - One of the best experts on this subject based on the ideXlab platform.
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Fractionation of Acacia Seyal gum by ion exchange chromatography
Food Hydrocolloids, 2020Co-Authors: Rafael Apolinar Valiente, Michaël Nigen, Pascale Williams, Thierry Doco, Véronica Mejia Tamayo, Christian SanchezAbstract:Acacia gum is a complex gum exudate from trees of selected Acacia species (i.e. A. senegal and A. Seyal). It is a continuum of molecular species showing diverse, sugar and protein composition, molar mass and charge density. Numerous studies have been conducted on several aspects of Acacia senegal gum (Asen), including its fractionation. Acacia Seyal gum (Asey) has been less studied, although it has recently been gaining importance. Certain gum characteristics, such as the protein and polysaccharide composition and the molecular parameters, play a key role in the Acacia gums functionality and, hence, in their uses by food, pharmaceutical or materials industries. Our main objective is to obtain a fraction from Asey gum with high molar mass and high protein content, allowing future research works and industrial applications. Asey gum has been separated by ion exchange chromatography (IEC) into two different fractions, IEC-F1 and IEC-F2, which have been thoroughly characterized. Thus, we have succeeded to recover a protein-rich fraction with high molar mass and high intrinsic viscosity, the fraction IEC-F1. The Mark-Houwink-Sakurada analysis further indicated that fraction IEC-F1 presents more anisotropic conformation compared to fraction IEC-F2. From the partial specific volume (v(s)degrees) and the partial specific adiabatic compressibility (beta(s)degrees) coefficients, a more flexible and less hydrated structure in the fraction IEC-F1 compared to Asey gum was suggested.
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fractionation of Acacia Seyal gum by ion exchange chromatography
Food Hydrocolloids, 2020Co-Authors: Rafael Apolinarvaliente, Michaël Nigen, Pascale Williams, Thierry Doco, Veronica Mejia Tamayo, Christian SanchezAbstract:Abstract Acacia gum is a complex gum exudate from trees of selected Acacia species (i.e. A. senegal and A. Seyal). It is a continuum of molecular species showing diverse, sugar and protein composition, molar mass and charge density. Numerous studies have been conducted on several aspects of Acacia senegal gum (Asen), including its fractionation. Acacia Seyal gum (Asey) has been less studied, although it has recently been gaining importance. Certain gum characteristics, such as the protein and polysaccharide composition and the molecular parameters, play a key role in the Acacia gums functionality and, hence, in their uses by food, pharmaceutical or materials industries. Our main objective is to obtain a fraction from Asey gum with high molar mass and high protein content, allowing future research works and industrial applications. Asey gum has been separated by ion exchange chromatography (IEC) into two different fractions, IEC-F1 and IEC-F2, which have been thoroughly characterized. Thus, we have succeeded to recover a protein-rich fraction with high molar mass and high intrinsic viscosity, the fraction IEC-F1. The Mark-Houwink-Sakurada analysis further indicated that fraction IEC-F1 presents more anisotropic conformation compared to fraction IEC-F2. From the partial specific volume (vs°) and the partial specific adiabatic compressibility (βs°) coefficients, a more flexible and less hydrated structure in the fraction IEC-F1 compared to Asey gum was suggested.
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surface properties of Acacia senegal vs Acacia Seyal films and impact on specific functionalities
Food Hydrocolloids, 2018Co-Authors: Chutima Aphibanthammakit, Michaël Nigen, Christian Sanchez, Sebastien Gaucel, Pascale ChalierAbstract:Abstract The microstructure and surface properties of spin coated films were studied to determine the structuration of Acacia gum films depending on gum type and composition. The difference between A. Seyal and A. senegal films was clearly evidenced by surface morphology (SEM and AFM) and through the contact angle measurement: A. senegal films having a smoother and more hydrophobic surface ( θ = 62°) than A. Seyal films ( θ = 42°) characterized by aggregated structuration. The film hydrophobicity increased with glycerol addition for both gum films (A. senegal, θ = 68° and A. Seyal, θ = 50°). This could be due to hydrogen-bonding between hydroxyl groups of plasticizer and polar groups of Acacia gums favoring their reduction on films surface. Both gum films behave as dual polar surface showing high disperse component of free energy compared to the polar component. Both gums showed strong affinity for apolar compounds ( θ
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flexibility and hydration of amphiphilic hyperbranched arabinogalactan protein from plant exudate a volumetric perspective
Colloids and Interfaces, 2018Co-Authors: Veronica Mejia Tamayo, Michaël Nigen, Pascale Williams, Thierry Doco, Denis Renard, Rafael Apolinarvaliente, Christian SanchezAbstract:Plant Acacia gum exudates are composed by glycosylated hydroxyproline-rich proteins, which have a high proportion of heavily branched neutral and charged sugars in the polysaccharide moiety. These hyperbranched arabinogalactan-proteins (AGP) display a complexity arising from its composition, architecture, and conformation, but also from its polydispersity and capacity to form supramolecular assemblies. Flexibility and hydration partly determined colloidal and interfacial properties of AGPs. In the present article, these parameters were estimated based on measurements of density and sound velocity and the determination of volumetric parameters, e.g., partial specific volume (vs°) and coefficient of partial specific adiabatic compressibility coefficient (βs°). Measurements were done with Acacia senegal, Acacia Seyal, and fractions from the former separated according to their hydrophobicity by Hydrophobic Interaction Chromatography, i.e., HIC-F1, HIC-F2, and HIC-F3. Both gums presented close values of vs° and βs°. However, data on fractions suggested a less hydrated and more flexible structure of HIC-F3, in contrast to a less flexible and more hydrated structure of HIC-F2, and especially HIC-F1. The differences between the macromolecular fractions of A. senegal are significantly related to the fraction composition, protein/polysaccharide ratio, and type of amino acids and sugars, with a polysaccharide moiety mainly contributing to the global hydrophilicity and a protein part mainly contributing to the global hydrophobicity. These properties form the basis of hydration ability and flexibility of hyperbranched AGP from Acacia gums.
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Flexibility and hydration of amphiphilic hyperbranched arabinogalactan-protein from plant exudate: a volumetric perspective
Colloids and Interfaces, 2018Co-Authors: Véronica Mejia Tamayo, Michaël Nigen, Pascale Williams, Thierry Doco, Rafael Apolinar Valiente, Denis Renard, Christian SanchezAbstract:Plant Acacia gum exudates are composed by glycosylated hydroxyproline-rich proteins, which have a high proportion of heavily branched neutral and charged sugars in the polysaccharide moiety. These hyperbranched arabinogalactan-proteins (AGP) display a complexity arising from its composition, architecture, and conformation, but also from its polydispersity and capacity to form supramolecular assemblies. Flexibility and hydration partly determined colloidal and interfacial properties of AGPs. In the present article, these parameters were estimated based on measurements of density and sound velocity and the determination of volumetric parameters, e.g., partial specific volume (v(s)degrees) and coefficient of partial specific adiabatic compressibility coefficient (beta(s)degrees). Measurements were done with Acacia senegal, Acacia Seyal, and fractions from the former separated according to their hydrophobicity by Hydrophobic Interaction Chromatography, i.e., HIC-F1, HIC-F2, and HIC-F3. Both gums presented close values of v(s)degrees and beta(s)degrees. However, data on fractions suggested a less hydrated and more flexible structure of HIC-F3, in contrast to a less flexible and more hydrated structure of HIC-F2, and especially HIC-F1. The differences between the macromolecular fractions of A. senegal are significantly related to the fraction composition, protein/polysaccharide ratio, and type of amino acids and sugars, with a polysaccharide moiety mainly contributing to the global hydrophilicity and a protein part mainly contributing to the global hydrophobicity. These properties form the basis of hydration ability and flexibility of hyperbranched AGP from Acacia gums.
Saphwan Alassaf - One of the best experts on this subject based on the ideXlab platform.
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studies on Acacia gums part vii effect of exudates form and tree age on the characteristics of Acacia Seyal var Seyal and Acacia Seyal var fistula
Food Hydrocolloids, 2015Co-Authors: M Andresbrull, Glyn O Phillips, Ishragha G Abdalla, Jesus Cirre, James Edwards, Mohammed E Osman, Saphwan AlassafAbstract:Abstract Authenticated samples of Acacia Seyal var. Seyal and Acacia Seyal var. fistula have been investigated. Samples of each variety from young (5–7 years) and old trees (15–20 years) were collected during the same season from the Eldamazeen area of Sudan. For each variety, two types of gum exudates (seep and nodule form) were collected. The solubility, optical rotation, sugar composition, colour Gardner, viscosity, and molecular weights were measured. The rhamnose and uronic acid contents were higher in var. Seyal than var. fistula but the amount of arabinose is greatest in var. fistula . The galactose content is almost the same for all samples with the possible exception of var. Seyal with a higher content in older trees. The weight average molecular weight (M w ) for var. fistula is almost double that of var. Seyal and generally the proportion of the high molecular fraction increases with age. The average value for the M w of the arabinogalactan moiety (AG) is 6.2 × 10 5 and 9.3 × 10 5 g/mol for Seyal and fistula respectively. Tannin content is highest in seep (∼0.8 wt%), lowest in the nodule form (0.08 wt%) and is a contaminant resulting directly from contact of the gum exudate with the tree bark. Tannin content increases with the age of tree for Seyal var. Seyal but not for var. fistula samples. These results give a clear difference between these two Acacia gum varieties, both of which are currently regulatory approved as gum arabic for food use.
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studies on Acacia exudate gums part vi interfacial rheology of Acacia senegal and Acacia Seyal
Food Hydrocolloids, 2008Co-Authors: Mona Elmanan, Glyn O Phillips, Saphwan Alassaf, Peter A. WilliamsAbstract:The effect of concentration, ageing and enzyme degradation on the interfacial rheology at the liquid/air (L/A) and liquid/liquid (L/L) interface of aqueous solutions of the gum exudates from Acacia senegal and Acacia Seyal have been studied. Both gums had film forming capabilities which increased as a function of time and concentration. The interfacial elasticity of the A. senegal gum samples was greater than that of the A. Seyal gums and increased with increasing arabinogalactan protein (AGP) content of the A. senegal gums and their overall protein content. When the AGP was degraded by proteolytic enzyme the interfacial viscoelasticity was lost for both A. senegal and A. Seyal gums. The different interfacial elasticity and viscosity of these two gums at the oil–water interface may reflect their well known differing abilities to maintain long term emulsion stability.
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studies on Acacia exudate gums part iv distribution of molecular components in Acacia Seyal in relation to Acacia senegal
Food Hydrocolloids, 2005Co-Authors: N E Siddig, Glyn O Phillips, Mohammed E Osman, Saphwan Alassaf, P A WilliamsAbstract:Abstract Acacia Seyal was fractionated on the basis of molecular size and hydrophobicity into a number of fractions. The molecular weight of the whole gum and its fractions were determined using gel permeation chromatography (GPC) with on-line monitoring using light scattering, refractive index and UV absorbance detectors. The results show that the three main components designated arabinogalactan protein (AGP), arabinogalactan (AG) and glycoprotein (GP) known to be present in Acacia senegal could also be present in A. Seyal . However, in A. senegal , the high molecular weight AGP component is more significant and is present in greater proportion than for A. Seyal . The most important difference is that at least two components are present in the high molecular weight fraction in A. Seyal , indicating that it would be erroneous to identify this completely with the AGP fraction in A. senegal .
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studies on Acacia exudate gums part v structural features of Acacia Seyal
Food Hydrocolloids, 2005Co-Authors: C Flindt, Glyn O Phillips, Saphwan Alassaf, P A WilliamsAbstract:An investigation of the molecular structure of Acacia Seyal relative to Acacia senegal provides an indication of the components which influence emulsification effectiveness. Samples of A. Seyal var. Seyal and A. Seyal var. fistula were fractionated using gel permeation chromatography. The fractions and the whole gum were analysed to determine the molecular weight, sugar content, amino acid, protein content, nitrogen, and intrinsic viscosity. The results confirm earlier findings that samples of A. Seyal, as a broad grouping, have weight average molecular weights several times greater than A. senegal, due to the greater proportion of the high molecular weight component. Although the molecular weight of A. Seyal is considerably greater than A. senegal, the intrinsic viscosity is less. The structure is, therefore, more compact, than the structure of A. senegal. The sugar composition and amino acids in each of the gums are identical but are present in different proportions, which is the main reason why A. Seyal is dextrorotatory and A. senegal is laevorotatory. The distribution of the protein is different between the various components which constitute the gums. In A. senegal the protein is mainly located in association with the high molecular weight component (AGP-peak 1). Enzyme hydrolysis points to two components being associated with the high molecular weight material in A. Seyal, only one of which is degraded by the enzyme pronase. In hydrophobic fractionation studies, a protein rich component of extremely high molecular weight (Fraction 3) was found in A. Seyal but not in A. senegal. In size fractionation this would co-elute with the main component, which is further evidence for the presence of the two different high molecular weight components in A. Seyal, unlike A. senegal. The adsorption of these high molecular weight protein fractions of A. Seyal onto an oil droplet was tested and found not to be a highly efficient emulsifying component. Structurally, while A. Seyal may have the same core structural linkages as A. senegal, the degree of branching is greater, with the protein distributed differently.
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studies on Acacia gums part iii molecular weight characteristics of Acacia Seyal var Seyal and Acacia Seyal var fistula
Food Hydrocolloids, 2005Co-Authors: E A Hassan, Glyn O Phillips, Saphwan Alassaf, P A WilliamsAbstract:Seventy four authenticated A. Seyal samples have been studied in order to establish the molecular characteristics of this important species and the differences between the two variants A. Seyal var. Seyal (ASS) and A. Seyal var. fistula (ASF) belonging to the Gummiferae series. Comparison is thus possible with A. senegal from the Vulgares series. The weight average molecular weight of A. Seyal is at least three times greater than A. senegal. From average values ASF has a significantly higher molecular weight than ASS, contains less protein and more inorganic ash residue. Yet despite the high molecular weight, the intrinsic viscosities of ASF and ASS are less than for A. senegal, indicating a more compact molecular structure, which is supported by the root mean square radii measurements giving molecular size ratios of A. Seyal to A. senegal of 0.77–1. The protein distribution in A. Seyal is different, and whereas the protein in A. senegal is mainly associated with the high molecular weight component (AGP∼106) it is distributed differently and mainly associated with a lower molecular weight component in A. Seyal. The Mark-Houwink plots for A. senegal confirm the differences in shape and size compared with A. Seyal. The average molecular weight for ASF is 2.1×106, for ASS 1.7×106 compared with an average value of 0.6×106 for AS.
Michaël Nigen - One of the best experts on this subject based on the ideXlab platform.
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Fractionation of Acacia Seyal gum by ion exchange chromatography
Food Hydrocolloids, 2020Co-Authors: Rafael Apolinar Valiente, Michaël Nigen, Pascale Williams, Thierry Doco, Véronica Mejia Tamayo, Christian SanchezAbstract:Acacia gum is a complex gum exudate from trees of selected Acacia species (i.e. A. senegal and A. Seyal). It is a continuum of molecular species showing diverse, sugar and protein composition, molar mass and charge density. Numerous studies have been conducted on several aspects of Acacia senegal gum (Asen), including its fractionation. Acacia Seyal gum (Asey) has been less studied, although it has recently been gaining importance. Certain gum characteristics, such as the protein and polysaccharide composition and the molecular parameters, play a key role in the Acacia gums functionality and, hence, in their uses by food, pharmaceutical or materials industries. Our main objective is to obtain a fraction from Asey gum with high molar mass and high protein content, allowing future research works and industrial applications. Asey gum has been separated by ion exchange chromatography (IEC) into two different fractions, IEC-F1 and IEC-F2, which have been thoroughly characterized. Thus, we have succeeded to recover a protein-rich fraction with high molar mass and high intrinsic viscosity, the fraction IEC-F1. The Mark-Houwink-Sakurada analysis further indicated that fraction IEC-F1 presents more anisotropic conformation compared to fraction IEC-F2. From the partial specific volume (v(s)degrees) and the partial specific adiabatic compressibility (beta(s)degrees) coefficients, a more flexible and less hydrated structure in the fraction IEC-F1 compared to Asey gum was suggested.
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fractionation of Acacia Seyal gum by ion exchange chromatography
Food Hydrocolloids, 2020Co-Authors: Rafael Apolinarvaliente, Michaël Nigen, Pascale Williams, Thierry Doco, Veronica Mejia Tamayo, Christian SanchezAbstract:Abstract Acacia gum is a complex gum exudate from trees of selected Acacia species (i.e. A. senegal and A. Seyal). It is a continuum of molecular species showing diverse, sugar and protein composition, molar mass and charge density. Numerous studies have been conducted on several aspects of Acacia senegal gum (Asen), including its fractionation. Acacia Seyal gum (Asey) has been less studied, although it has recently been gaining importance. Certain gum characteristics, such as the protein and polysaccharide composition and the molecular parameters, play a key role in the Acacia gums functionality and, hence, in their uses by food, pharmaceutical or materials industries. Our main objective is to obtain a fraction from Asey gum with high molar mass and high protein content, allowing future research works and industrial applications. Asey gum has been separated by ion exchange chromatography (IEC) into two different fractions, IEC-F1 and IEC-F2, which have been thoroughly characterized. Thus, we have succeeded to recover a protein-rich fraction with high molar mass and high intrinsic viscosity, the fraction IEC-F1. The Mark-Houwink-Sakurada analysis further indicated that fraction IEC-F1 presents more anisotropic conformation compared to fraction IEC-F2. From the partial specific volume (vs°) and the partial specific adiabatic compressibility (βs°) coefficients, a more flexible and less hydrated structure in the fraction IEC-F1 compared to Asey gum was suggested.
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surface properties of Acacia senegal vs Acacia Seyal films and impact on specific functionalities
Food Hydrocolloids, 2018Co-Authors: Chutima Aphibanthammakit, Michaël Nigen, Christian Sanchez, Sebastien Gaucel, Pascale ChalierAbstract:Abstract The microstructure and surface properties of spin coated films were studied to determine the structuration of Acacia gum films depending on gum type and composition. The difference between A. Seyal and A. senegal films was clearly evidenced by surface morphology (SEM and AFM) and through the contact angle measurement: A. senegal films having a smoother and more hydrophobic surface ( θ = 62°) than A. Seyal films ( θ = 42°) characterized by aggregated structuration. The film hydrophobicity increased with glycerol addition for both gum films (A. senegal, θ = 68° and A. Seyal, θ = 50°). This could be due to hydrogen-bonding between hydroxyl groups of plasticizer and polar groups of Acacia gums favoring their reduction on films surface. Both gum films behave as dual polar surface showing high disperse component of free energy compared to the polar component. Both gums showed strong affinity for apolar compounds ( θ
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flexibility and hydration of amphiphilic hyperbranched arabinogalactan protein from plant exudate a volumetric perspective
Colloids and Interfaces, 2018Co-Authors: Veronica Mejia Tamayo, Michaël Nigen, Pascale Williams, Thierry Doco, Denis Renard, Rafael Apolinarvaliente, Christian SanchezAbstract:Plant Acacia gum exudates are composed by glycosylated hydroxyproline-rich proteins, which have a high proportion of heavily branched neutral and charged sugars in the polysaccharide moiety. These hyperbranched arabinogalactan-proteins (AGP) display a complexity arising from its composition, architecture, and conformation, but also from its polydispersity and capacity to form supramolecular assemblies. Flexibility and hydration partly determined colloidal and interfacial properties of AGPs. In the present article, these parameters were estimated based on measurements of density and sound velocity and the determination of volumetric parameters, e.g., partial specific volume (vs°) and coefficient of partial specific adiabatic compressibility coefficient (βs°). Measurements were done with Acacia senegal, Acacia Seyal, and fractions from the former separated according to their hydrophobicity by Hydrophobic Interaction Chromatography, i.e., HIC-F1, HIC-F2, and HIC-F3. Both gums presented close values of vs° and βs°. However, data on fractions suggested a less hydrated and more flexible structure of HIC-F3, in contrast to a less flexible and more hydrated structure of HIC-F2, and especially HIC-F1. The differences between the macromolecular fractions of A. senegal are significantly related to the fraction composition, protein/polysaccharide ratio, and type of amino acids and sugars, with a polysaccharide moiety mainly contributing to the global hydrophilicity and a protein part mainly contributing to the global hydrophobicity. These properties form the basis of hydration ability and flexibility of hyperbranched AGP from Acacia gums.
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Flexibility and hydration of amphiphilic hyperbranched arabinogalactan-protein from plant exudate: a volumetric perspective
Colloids and Interfaces, 2018Co-Authors: Véronica Mejia Tamayo, Michaël Nigen, Pascale Williams, Thierry Doco, Rafael Apolinar Valiente, Denis Renard, Christian SanchezAbstract:Plant Acacia gum exudates are composed by glycosylated hydroxyproline-rich proteins, which have a high proportion of heavily branched neutral and charged sugars in the polysaccharide moiety. These hyperbranched arabinogalactan-proteins (AGP) display a complexity arising from its composition, architecture, and conformation, but also from its polydispersity and capacity to form supramolecular assemblies. Flexibility and hydration partly determined colloidal and interfacial properties of AGPs. In the present article, these parameters were estimated based on measurements of density and sound velocity and the determination of volumetric parameters, e.g., partial specific volume (v(s)degrees) and coefficient of partial specific adiabatic compressibility coefficient (beta(s)degrees). Measurements were done with Acacia senegal, Acacia Seyal, and fractions from the former separated according to their hydrophobicity by Hydrophobic Interaction Chromatography, i.e., HIC-F1, HIC-F2, and HIC-F3. Both gums presented close values of v(s)degrees and beta(s)degrees. However, data on fractions suggested a less hydrated and more flexible structure of HIC-F3, in contrast to a less flexible and more hydrated structure of HIC-F2, and especially HIC-F1. The differences between the macromolecular fractions of A. senegal are significantly related to the fraction composition, protein/polysaccharide ratio, and type of amino acids and sugars, with a polysaccharide moiety mainly contributing to the global hydrophilicity and a protein part mainly contributing to the global hydrophobicity. These properties form the basis of hydration ability and flexibility of hyperbranched AGP from Acacia gums.
