The Experts below are selected from a list of 9009 Experts worldwide ranked by ideXlab platform
David Julian Mcclements - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of colour stability of anthocyanins in model beverages by Gum Arabic addition
Food Chemistry, 2016Co-Authors: Cheryl Chung, David Julian Mcclements, Thananunt Rojanasasithara, William MutilangiAbstract:This study investigated the potential of Gum Arabic to improve the stability of anthocyanins that are used in commercial beverages as natural colourants. The degradation of purple carrot anthocyanin in model beverage systems (pH 3.0) containing L-ascorbic acid proceeded with a first-order reaction rate during storage (40 °C for 5 days in light). The addition of Gum Arabic (0.05-5.0%) significantly enhanced the colour stability of anthocyanin, with the most stable systems observed at intermediate levels (1.5%). A further increase in concentration (>1.5%) reduced its efficacy due to a change in the conformation of the Gum Arabic molecules that hindered their exposure to the anthocyanins. Fluorescence quenching measurements showed that the anthocyanin could have interacted with the glycoprotein fractions of the Gum Arabic through hydrogen bonding, resulting in enhanced stability. Overall, this study provides valuable information about enhancing the stability of anthocyanins in beverage systems using natural ingredients.
-
antimicrobial delivery systems based on electrostatic complexes of cationic ɛ polylysine and anionic Gum Arabic
Food Hydrocolloids, 2014Co-Authors: Lynne Mclandsborough, Yuhua Chang, David Julian McclementsAbstract:ɛ-Polylysine (ɛ-PL) is a potent food-grade cationic antimicrobial but its application within foods and beverages is currently limited because of its tendency to associate with anionic substances, thereby increasing product turbidity or forming sediments. In this study, we examined a potential means of overcoming these problems by forming electrostatic complexes between cationic ɛ-PL and anionic Gum Arabic (GA). The nature of the complexes formed depended on the mass ratio of Gum Arabic-to-ɛ-PL (RGA–PL), since this determined their electrical charge, aggregation stability, and antimicrobial efficacy. The electrical charge on the complexes went from positive to negative with increasing RGA–PL, with the point of zero charge being around RGA–PL ∼15. Soluble complexes were formed at low and high RGA–PL levels, but insoluble complexes were formed at intermediate levels (i.e. 5 < RGA–PL < 25). The antimicrobial activities of the ɛ-PL–GA complexes were investigated in a model beverage system against two acid resistant spoilage yeasts: Zygosaccharomyces bailii (ZB) and Saccharomyces cerevisiae (SC). In general, the antimicrobial efficacy of ɛ-PL decreased with increasing amount of GA, and this effect also depended on microorganism type, with SC being less sensitive to increased levels of Gum Arabic than ZB. Finally, we showed that certain ɛ-PL–GA complexes (15 μg/mL ɛ-PL; RGA–PL ≥ 20) could be incorporated into model beverages without adversely affecting their appearance or physical stability. This work has shown that the function of a cationic antimicrobial (ɛ-polylysine) can be improved by incorporating it within electrostatic complexes using a food-grade anionic biopolymer (Gum Arabic).
-
comparison of Gum Arabic modified starch and whey protein isolate as emulsifiers influence of ph cacl2 and temperature
Journal of Food Science, 2002Co-Authors: Ratjika Chanamai, David Julian McclementsAbstract:: The particle size and zeta potential of model beverage emulsions (0.01 wt% soybean oil-in-water emulsions, d ≅ 1 mm) stabilized by Gum Arabic, modified starch, or whey protein isolate (WPI) were studied with varying pH (3 to 9), CaCl2 concentration (0 to 25 mM), and temperature (30 °C to 90 °C). Temperature, pH, CaCl2 strongly influenced emulsions stabilized by WPI because its stabilizing mechanism was mainly electrostatic repulsion, but not those stabilized by Gum Arabic or modified starch because their stabilizing modes of action were mainly steric repulsion. This study may have important implications for the application of WPI as an emulsifier in beverage emulsions.
-
depletion flocculation of beverage emulsions by Gum Arabic and modified starch
Journal of Food Science, 2001Co-Authors: Ratjika Chanamai, David Julian McclementsAbstract:ABSTRACT: The creaming velocity, apparent viscosity, and ultrasonic attenuation spectra (1 to 50 MHz) of 5 wt% n hexadecane oil-in-water emulsions containing different droplet radii (r = 0.15 - 0.7 μm), biopolymer types (Gum Arabic or modified starch), and biopolymer concentrations (0 to 2.5 wt%) were measured. Depletion flocculation was observed in the emulsions when the nonabsorbed biopolymer concentration exceeded a critical concentration (CFC). The CFC increased with decreasing droplet radius for both biopolymers because the magnitude of the depletion attraction increases with droplet size. The CFC was lower for Gum Arabic than modified starch because it has a higher effective volume in solution. Depletion flocculation led to an increase in creaming instability and apparent viscosity of the emulsions. Flocculation could be nondestructively monitored by measuring the decrease in ultrasonic attenuation of the emulsions. These results show that depletion flocculation by Gum Arabic and modified starch can have an adverse effect on the stability of beverage emulsions.
Rekha Satishchandra Singhal - One of the best experts on this subject based on the ideXlab platform.
-
Hydrophobic derivatives of guar Gum hydrolyzate and Gum Arabic as matrices for microencapsulation of mint oil
Carbohydrate Polymers, 2013Co-Authors: Shatabhisa Sarkar, Sumit Gupta, Prasad Shekhar Variyar, Arun Sharma, Rekha Satishchandra SinghalAbstract:Guar Gum hydrolyzate (GGH) modified with n-octenyl succinic anhydride (OSA) and oleic acid having induced hydrophobicity was evaluated for encapsulation of mint oil and compared with Gum Arabic (GA) and GA-OSA as wall material. Spray dried microcapsules prepared with these wall materials were evaluated for qualitative changes by principal component analysis and for percent retention of mint oil during 8-week storage. Results revealed that microcapsules with GGH-OSA and GGH-oleate showed slightly lower retention of mint oil as compared to GA. GA-OSA microcapsules showed better retention of mint oil than GA itself, as observed from the t1/2, the time required for the mint oil to come down to 50% of its original content. The t1/2 of mint oil in microcapsules of GA, GGH-oleate, GGH-OSA and GA-OSA was 26.12, 23.50, 24.11 and 29.67 weeks, respectively. The results suggested that GGH-OSA has the potential to replace Gum Arabic for encapsulation of mint oil.
-
stability of cumin oleoresin microencapsulated in different combination of Gum Arabic maltodextrin and modified starch
Carbohydrate Polymers, 2007Co-Authors: Dattanand Kanakdande, Rajesh Bhosale, Rekha Satishchandra SinghalAbstract:Abstract Microencapsulations of cumin oleoresin by spray drying using Gum Arabic, maltodextrin, and modified starch (HiCap ® 100) and their ternary blends as wall materials were studied for its encapsulation efficiency and stability under storage. The microcapsules were evaluated for the content and stability of volatiles, and total cuminaldehyde, γ-terpinene and p -cymene content for six weeks. Gum Arabic offered greater protection than maltodextrin and modified starch, in general, although the order of protection offered was volatiles > cuminaldehyde > p -cymene > γ-terpinene. A 4/6:1/6:1/6 blend of Gum Arabic/maltodextrin/modified starch offered a protection, better than Gum Arabic as seen from the t 1/2 , i.e. time required for a constituent to reduce to 50% of its initial value. However protective effect of ternary blend was not similar for the all the constituents, and followed an order of volatiles > p -cymene > cuminaldehyde > γ-terpinene.
-
the use of Gum Arabic and modified starch in the microencapsulation of a food flavoring agent
Carbohydrate Polymers, 2005Co-Authors: Savitha Krishnan, Atul Chandrakant Kshirsagar, Rekha Satishchandra SinghalAbstract:Solvent extracted oleoresins exhibit a flavor profile, close to the freshly ground spice in a wide spectrum of foods. In spite of their many advantages over ground spices, their sensitivity to light, heat and oxygen is a disadvantage. One approach to overcome this disadvantage is by means of microencapsulation. The present work reports on microencapsulation of cardamom oleoresin by spray drying using Gum Arabic, maltodextrin, and a commercially available modified starch as wall materials. The microcapsules were evaluated for the content and stability of volatiles, non-volatiles, entrapped 1,8-cineole and entrapped α-terpinyl acetate for 6 weeks. Gum Arabic offered greater protection to the oleoresin than maltodextrin and modified starch, as seen from the t1/2, time required for a constituent to reduce to 50% of its initial value.
-
microencapsulation of cardamom oleoresin evaluation of blends of Gum Arabic maltodextrin and a modified starch as wall materials
Carbohydrate Polymers, 2005Co-Authors: Savitha Krishnan, Rajesh Bhosale, Rekha Satishchandra SinghalAbstract:Abstract Although the spice oleoresins provide complete flavour profile than their respective essential oils, their sensitivity to the light, heat and oxygen is a disadvantage. This can be overcome by effective encapsulation. The present work reports on the microencapsulation of cardamom oleoresin by spray drying using binary and ternary blends of Gum Arabic, maltodextrin, and modified starch as wall materials. The microcapsules were evaluated for the content and stability of volatiles, entrapped 1,8-cineole and entrapped α-terpinyl acetate for 6 weeks. A 4/6,1/6,1/6 blend of Gum Arabic:maltodextrin:modified starch offered a protection, better than Gum Arabic as seen from the t 1/2 , time required for a constituent to reduce to 50% of its initial value.
Pelin Gunc Ergonul - One of the best experts on this subject based on the ideXlab platform.
-
optimisation of wall material composition of freeze dried pumpkin seed oil microcapsules interaction effects of whey protein maltodextrin and Gum Arabic by d optimal mixture design approach
Food Hydrocolloids, 2020Co-Authors: Zeynep Aksoylu Ozbek, Pelin Gunc ErgonulAbstract:Abstract D–optimal mixture design approach was used for optimisation of wall material composition including whey protein concentrate (WPC), maltodextrin, and Gum Arabic to effectively encapsulate cold–pressed pumpkin seed oil (CPPSO) by freeze–drying. Interaction and/or synergistic effects of these wall materials on the rheological and physical properties of oil–in–water emulsions and some physicochemical characteristics of microcapsules were examined. Rather than individual effects of each wall material component, effects of their interactions were dominant on the quality attributes of emulsions and microcapsules. Microencapsulation by freeze–drying decreased α–, γ– and total tocopherols and total phenolic contents (TPC) of CPPSO. Two wall material compositions (12.28% WPC + 5% maltodextrin +2.70% Gum Arabic or 10% WPC + 5% maltodextrin +5% Gum Arabic) with increased emulsion stability, encapsulation efficiency, solubility, total polyunsaturated fatty acids (PUFA) content and decreased wettability time and total saturated fatty acids (SFA) content were predicted by optimisation tool.
Glyn O Phillips - One of the best experts on this subject based on the ideXlab platform.
-
synthesis and antioxidant properties of Gum Arabic stabilized selenium nanoparticles
International Journal of Biological Macromolecules, 2014Co-Authors: Huiling Kong, Katsuyoshi Nishinari, Yapeng Fang, Jixin Yang, Yifeng Zhang, Glyn O PhillipsAbstract:Abstract Selenium nanoparticles (SeNPs) were prepared by using Gum Arabic (GA) as the stabilizer in a facile synthetic approach. The size, morphology, stability and antioxidant activity in vitro of the Gum Arabic-selenium nanocomposites (GA-SeNPs) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and ultraviolet–visible spectrophotometry (UV–vis). SeNPs (particle size of ∼34.9 nm) can be stabilized in Gum Arabic aqueous solutions for approximately 30 days. FTIR results show that SeNPs were combined to the hydroxyl groups of GA. In the present work, the alkali-hydrolyzed GA (AHGA) was also prepared and its efficiency in stabilizing SeNPs was compared with GA. It was concluded that the branched structure of GA was a significant factor for the functionality. The hydroxyl radical scavenging ability and DPPH scavenging ability of GA-SeNPs were higher than those of AHGA-SeNPs and could reach 85.3 ± 2.6%, 85.3 ± 1.9% at a concentration of 4 mg/ml, respectively.
-
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.
-
a further amendment to the classical core structure of Gum Arabic acacia senegal
Food Hydrocolloids, 2013Co-Authors: Steve W Cui, Shaoping Nie, Cathy Wang, Qi Wang, Mingyong Xie, Glyn O PhillipsAbstract:Using the more recently available techniques such as methylation–GC–MS, 1D (1H, 13C) and 2D (COSY, TOCSY, HMQC and HMBC) NMR spectral analysis, we have revisited the classical structure of Gum Arabic (Acacia senegal). Methylation and GC–MS analysis confirmed that Gum Arabic (A. senegal) is a highly branched polysaccharide with the backbone composed of 1,3-linked galactopyransyl (Galp) residues substituted at O-2, O-6 or O-4 positions. The terminal sugar residues are 59.5% of the total sugars. The residues of →2,3,6-β-d-Galp1→, →3,4-Galp1→, →3,4,6-Galp1→ and substitutions at O-2 and O-4 position were not identified in previous studies.
-
rheological properties of Gum Arabic solution from newtonianism to thixotropy
Food Hydrocolloids, 2011Co-Authors: Yapeng Fang, Katsuyoshi Nishinari, Hongbin Zhang, Saphwan Alassaf, Glyn O PhillipsAbstract:Abstract The influence of molecular association on the rheological behavior of Gum Arabic solution was studied. Using time-dependence of transient shear stress a reversible molecular association could be arrested and the thixotropy of Gum Arabic solution was interpreted. The structural breakdown, buildup and the effect of shear history due to molecular association could be related using the Casson’s equation. Stress jump measurements distinguished the effect of molecular association on the elastic and viscous contributions of shear stress. An elastic-like contribution dominated at low shear rates whereas the viscous component became important at high shear rates. The elastic contribution was strongly affected by the molecular association of Gum Arabic, with increased molecular association contributing to a larger elastic contribution. The elastic and viscous contributions were also investigated in transient flow. Both of the contributions increased with rest time, indicating a buildup of molecular association. With increasing the rest time the elastic contribution increased much faster than the viscous contribution to the total stress.
-
new insights into the structural characteristics of the arabinogalactan protein agp fraction of Gum Arabic
Journal of Agricultural and Food Chemistry, 2008Co-Authors: T Mahendran, Glyn O Phillips, Saphwan Alassaf, P A Williams, T C BaldwinAbstract:The structural characteristics of the Gum exudate of Acacia senegal (Gum Arabic) have been investigated by monitoring the composition and physicochemical properties before and after treatment with proteolytic enzyme and various alkaline systems. Molecular mass ( M w) and radius of gyration ( R g) measurements were performed using gel permeation chromatography (GPC) coupled to refractive index, UV absorbance, and multiangle light scattering detectors and indicated that the macromolecules present have a compact structure. It was found that treatment with proteolytic enzyme caused the arabinogalactan-protein component (AGP) with average molecular mass approximately 2 x 10 (6) Da to degrade, yielding material of molecular mass approximately 4 x 10 (5) Da, whereas the bulk of the material corresponding to the protein-deficient arabinogalactan component (AG) with molecular mass 4 x 10 (5) remained unaffected. Barium hydroxide was found to hydrolyze the polysaccharide component (AG) itself in addition to the proteinaceous component as demonstrated in control experiments using dextran. However, sodium borohydride/sodium hydroxide treatments were unable to hydrolyze dextran and were assumed to hydrolyze only the proteinaceous component of Gum Arabic. The AGP component was completely degraded, yielding material of molecular mass approximately 4.5 x 10 (4) Da. It has been concluded, therefore, that the enzyme did not fully hydrolyze all of the protein present and that the AGP component of Gum Arabic consists of carbohydrate blocks of approximately 4.5 x 10 (4) Da linked to a polypeptide chain consistent with the wattle blossom structure. Because the AGP was degraded to differing extents using a mild and more severe sodium borohydride/sodium hydroxide treatment, it was concluded that the polysaccharide moieties were linked through both O-serine and O-hydroxyproline residues. The Gum Arabic sample was deglycosylated by treatment with anhydrous hydrogen fluoride and revealed the presence of two putative core proteins of approximately 3 x 10 (4) and approximately 5 x 10 (3) Da, respectively, which correspond to proteins of approximately 250 and 45 amino acids in length. A new model for the structure of the AGP component has been proposed.
Zeynep Aksoylu Ozbek - One of the best experts on this subject based on the ideXlab platform.
-
optimisation of wall material composition of freeze dried pumpkin seed oil microcapsules interaction effects of whey protein maltodextrin and Gum Arabic by d optimal mixture design approach
Food Hydrocolloids, 2020Co-Authors: Zeynep Aksoylu Ozbek, Pelin Gunc ErgonulAbstract:Abstract D–optimal mixture design approach was used for optimisation of wall material composition including whey protein concentrate (WPC), maltodextrin, and Gum Arabic to effectively encapsulate cold–pressed pumpkin seed oil (CPPSO) by freeze–drying. Interaction and/or synergistic effects of these wall materials on the rheological and physical properties of oil–in–water emulsions and some physicochemical characteristics of microcapsules were examined. Rather than individual effects of each wall material component, effects of their interactions were dominant on the quality attributes of emulsions and microcapsules. Microencapsulation by freeze–drying decreased α–, γ– and total tocopherols and total phenolic contents (TPC) of CPPSO. Two wall material compositions (12.28% WPC + 5% maltodextrin +2.70% Gum Arabic or 10% WPC + 5% maltodextrin +5% Gum Arabic) with increased emulsion stability, encapsulation efficiency, solubility, total polyunsaturated fatty acids (PUFA) content and decreased wettability time and total saturated fatty acids (SFA) content were predicted by optimisation tool.