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This study focuses on understanding the effect of ionic strength on the mechanical and microstructural properties of novel composite gels containing 13% whey protein isolate (WPI) and 4% de-structured waxy potato starch (DWPS). The DWPS... more
This study focuses on understanding the effect of ionic strength on the mechanical and microstructural properties of novel composite gels containing 13% whey protein isolate (WPI) and 4% de-structured waxy potato starch (DWPS). The DWPS is a physically modified waxy potato starch treated at 140 °C for 30 min under constant shear. Thermodynamic incompatibility between WPI and DWPS was observed upon the addition of NaCl (~75 mM) or CaCl2 (10–75 mM). The combined effects of such thermodynamic incompatibility with the changes in protein connectivity induced by varied ionic strength led to the formation of distinctive gel structures (inhomogeneous self-supporting gels with a liquid centre and weak gels with paste-like consistency) that were different from thermodynamic compatible homogeneous self-supporting gels (pure WPI and WPI + maltodextrin gels). At ≥ 250 mM NaCl, instead of a paste-like texture, a recovered soft and creamy self-supporting gel structure was observed when using DWPS....
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We report on the properties of analogue cream cheeses prepared using glucono delta-lactone (GDL) acidulant, notably the impact of particular processing and formulation variables, (homogenisation pressure, coagulation pH and temperature,... more
We report on the properties of analogue cream cheeses prepared using glucono delta-lactone (GDL) acidulant, notably the impact of particular processing and formulation variables, (homogenisation pressure, coagulation pH and temperature, and stabiliser level) on cream cheese physical, material and microstructural properties. Protein–protein and protein-fat interactions were seen to be the primary structural contributors to the physical properties of cream cheese. Cream cheese microstructure and its properties demonstrated well-defined correlations to specific and controllable processing elements within the manufacturing process, showing significance in interactions between parameters in multivariable linear regression analysis (P < 0.05). Summarising the effect of processing variables on key cheese properties, we observed that a progressive reduction in fat particle size of cheese milk arising from increasing homogenisation pressures was seen to increase the total surface area of ...
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White bread contains a high proportion of easily digestible starch, which contributes to an undesirable rapid increase in blood glucose concentration. This study investigated the effects of nonstarch polysaccharides (NSP) -xanthan gum,... more
White bread contains a high proportion of easily digestible starch, which contributes to an undesirable rapid increase in blood glucose concentration. This study investigated the effects of nonstarch polysaccharides (NSP) -xanthan gum, lambda-carrageenan and psyllium husk on the physical functionality and glycaemic potency of white bread. The amount of water for each formulation was adjusted based on DoughLab set at a target torque value of ~500 FU for sufficient dough development. Adding NSP generally resulted in significantly increased loaf volumes and decreased hardness. The glycaemic potency (glycaemic glucose equivalents (GGE) g) of bread was found to be reduced with the addition of NSP at all levels (1, 3 and 5% w/w based on flour weight). Increasing the concentration of xanthan gum and lambda-carrageenan did not show any further decrease in the glycaemic potency. Notably, adding 5% w/w psyllium husk significantly reduced the glycaemic potency from ~49 GGE/100 g in the referen...
Research Interests: Chemistry, Food Science, Starch, Xanthan Gum, Foods, and 5 moreCarrageenan, Potency, polysaccharide, Psyllium, and husk
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The digestibility of wheat starch gels in the presence of Mesona chinensis polysaccharide (MCP) was studied.
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Research Interests: Chemistry, Food Science, Rheology, Calcium, Starch, and 5 moreAnimal Production, In Vitro, Food Sciences, LWT, and polysaccharide
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J6 - STUDENT - A novel food stabilizer extracted from Ocimum basilicum L. seeds: a ideological study SeyedH. Hosseini-Parvar1-\ SeyedA. Mortazavi1, SeyedM.A Razavi', Lara Matia-Merino^ Kelvin KT. Goti3. Ali Motamedzadegan1 1 Ferdowsi... more
J6 - STUDENT - A novel food stabilizer extracted from Ocimum basilicum L. seeds: a ideological study SeyedH. Hosseini-Parvar1-\ SeyedA. Mortazavi1, SeyedM.A Razavi', Lara Matia-Merino^ Kelvin KT. Goti3. Ali Motamedzadegan1 1 Ferdowsi University of ...
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The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB - reference), (2) 75% of kibbled purple... more
The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB - reference), (2) 75% of kibbled purple wheat in 25% white bread matrix (PB), (3) a 1:1 mixture of 37.5% kibbled soy beans and 37.5% of kibble purple wheat in 25% white bread matrix (SPB). Each bread was ingested in three forms: unchewed (U), as customarily consumed (C), and homogenized (H). Twelve participants ingested 40 g available carbohydrate portions of each bread in each form, with post prandial blood glucose measured over 120 min. Glycaemic responses to WB were the same regardless of its form when ingested. Unchewed PB had significantly less glycaemic effect than WB, whereas the C and H forms were similar to WB. Based on a glycaemic index (GI) of 70 for WB the GI values for the C, U and H breads respectively were WB: 70.0, 70, 70, PB: 75, 42, 61, SPB: 57, 48, 55 (%) (Least significant...
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Summary Basil seed (Ocimum basilicum L.) is cultivated in large quantities in different regions of Iran. This seed has reasonable amounts of gum with good functional properties which is comparable with commercial food hydrocolloids. A... more
Summary Basil seed (Ocimum basilicum L.) is cultivated in large quantities in different regions of Iran. This seed has reasonable amounts of gum with good functional properties which is comparable with commercial food hydrocolloids. A central composite rotatable design was applied to evaluate the effects of temperature, pH and water ⁄ seed ratio on the yield, apparent viscosity and protein content of water-extracted Basil seed gum. All of the variables significantly (P 0.05). Numerical optimisation determined the optimum extraction conditions based on the highest yield and viscosity and the lowest protein content as being temperature 68.71 � C, pH 8.09 and water ⁄ seed ratio 65.98:1. Power law model well described non-Newtonian pseudoplastic behaviour of BSG. Flow behaviour index (n) and consistency index (K) of 1% crude and pure BSG samples were 0.306, 0.283 and 17.46, 20.22 Pa s n , respectively.
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Review(s) of: The Chemical Physics of Food, Edited by Peter Belton, Blackwell Publishing Ltd, 2007, 274 pp. ISBN: 1405121270.
We investigated the effects of Tween emulsifier fatty acid chain length on the shear stability and crystallization behavior of 35 wt% partially crystalline oil-in-water emulsions prepared with and without 1 wt% sodium caseinate. Emulsions... more
We investigated the effects of Tween emulsifier fatty acid chain length on the shear stability and crystallization behavior of 35 wt% partially crystalline oil-in-water emulsions prepared with and without 1 wt% sodium caseinate. Emulsions containing sodium caseinate and Tween 20, 40, 60 or 80 varied in shear stability, degree of supercooling and crystallization behavior depending on the type and concentration of Tween as well as the presence of protein. Generally, emulsions containing the unsaturated emulsifier Tween 80 were the most shear sensitive followed by the saturated emulsifiers Tween 20, 40 and 60 in order of increasing fatty acid chain length. Long chain saturated Tween emulsifiers (40 and 60) improved shear stability regardless of whether sodium caseinate was present indicating that alone, these emulsifiers form more robust interfacial films compared to the saturated short chain length Tween 20 and Tween 80. In emulsions prepared with sodium caseinate, the degree of supercooling decreased and the crystallization rate diminished with increasing saturated fatty acid chain length but only negligible changes were found without sodium caseinate. Together, these findings indicate that long chain saturated Tween emulsifiers provide better emulsion stability regardless of the presence of sodium caseinate but with sodium caseinate, stability may also be affected by changes to fat crystallization. These novel findings provide guidance on how combinations of proteins and emulsifiers can be used to modify and control the stability of partially crystalline oil-in-water emulsions through their combined effects on the properties of the interfacial film and fat crystallization.
The interaction between wheat starch and Mesona chinensis polysaccharide (MCP) was found to change the molecular mobility of the water and carbohydrate populations in starch-MCP gels, when measured using proton and carbon nuclear magnetic... more
The interaction between wheat starch and Mesona chinensis polysaccharide (MCP) was found to change the molecular mobility of the water and carbohydrate populations in starch-MCP gels, when measured using proton and carbon nuclear magnetic resonance relaxation methods. The starch and MCP mobilities appeared similar at a micron scale. However, at a distance of less than 5 nm could they be detected as having separate mobility states, indicating close interaction between the starch and MCP. The carbon-6 of the starch glucan monomer was observed to have the largest mobility change in the presence of MCP. Two mobility populations of carbon-6 were observed, possibly corresponding to the carbon-6 in the linear chains of both amylose and amylopectin, and another to the carbon-6 involved in the branching of amylopectin. The change in the mobility of one of the carbon-6 populations indicates an increase in molecular freedom of movement in the presence of MCP.
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Abstract Composite Mesona chinensis polysaccharide (MCP) and wheat starch gels were studied using solid-state NMR, whereby close proximity (5 A) between MCP and glucan polymers was established, indicating that both polymers interacted at... more
Abstract Composite Mesona chinensis polysaccharide (MCP) and wheat starch gels were studied using solid-state NMR, whereby close proximity (5 A) between MCP and glucan polymers was established, indicating that both polymers interacted at molecular level. Rheological and amylose leaching data showed that this interaction was primarily between MCP and amylose leached during gelatinisation. The elastic modulus ( G′ ) and hardness of gels containing high starch concentration (≥8% w/w) was decreased at low ( G′ and hardness of the gels, and accelerated their retrogradation.
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Abstract The emulsion stability and rheological properties of heated (120 °C, 0 – 60 min) 30% w/w oil-in-water emulsions (droplet diameter ∼ 0.73 μm, pH 6.8) containing sodium caseinate (Na-CN), 2 – 6% w/w, were investigated. The creaming... more
Abstract The emulsion stability and rheological properties of heated (120 °C, 0 – 60 min) 30% w/w oil-in-water emulsions (droplet diameter ∼ 0.73 μm, pH 6.8) containing sodium caseinate (Na-CN), 2 – 6% w/w, were investigated. The creaming kinetics, determined by multiple light scattering (Turbiscan), showed that the phase separation of Na-CN-stabilized emulsions was markedly dependent on the duration of the heat treatment. The differences between unheated and heated emulsions were attributed to heat-induced physicochemical changes in the aqueous Na-CN nanoparticles. The heat treatment caused protein degradation and changed the intact Na-CN concentration in the continuous phase. The emulsion structures, with varied extents of depletion flocculation, were well reflected by small and large deformation rheology. In the recombined Na-CN emulsions, the depletion attraction was weakened at low and moderate Na-CN concentrations (2% and 4% w/w) but was strengthened at high Na-CN concentration (6% w/w). The former structural change was predominantly due to reduced depletion attraction, whereas reduced depletion attraction and decreased continuous phase viscosity influenced the latter structural change. The intact Na-CN concentration in the continuous phase is determined by the heat-induced physicochemical changes of Na-CN nanoparticles, which played a significant role in the physical stability of the emulsions. The insights from this study can be used to create novel droplet sizes and protein particle sizes to manipulate the droplet/protein size ratio, and therefore the extent of droplet−droplet interactions.
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Abstract The stabilisation of insoluble lignin microparticulates produced through solvent attrition in aqueous media containing surfactants has been investigated. In the absence of added surfactants, addition of solvent solubilised lignin... more
Abstract The stabilisation of insoluble lignin microparticulates produced through solvent attrition in aqueous media containing surfactants has been investigated. In the absence of added surfactants, addition of solvent solubilised lignin to water caused extensive precipitation and annealing of lignin, leading to the formation of large, agglomerated structures in the approximate size range of 20–200 μm. Addition of high HLB non-ionic surfactants (Polysorbate 20/sucrose ester) to the aqueous solution prior to lignin precipitation had only limited effect on the size of agglomerates produced, with a partial decrease in mean aggregate size at elevated surfactant concentrations, and no observed effect at low surfactant concentrations. In contrast, addition of either negatively (SDS) or positively (CTAB) charged ionic surfactants at concentrations Findings indicate that adsorption of charged surfactants to the surface of lignin particles during precipitation is able to provide effective electrostatic stabilisation; however, no such stabilising effect is provided by non-ionic surfactants. Furthermore, it appears that the size and stability of the particles produced is dependent on the conditions within the aqueous phase during precipitation. In this way, it may be possible to produce lignin microparticles with tailored particle distributions.
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The shear-thickening rheological behaviour (between 5 and 20s(-1)) of a 5% (w/w) viscoelastic gum extracted from the fronds of the native New Zealand black tree fern or mamaku in Māori was further explored by manipulating the salt... more
The shear-thickening rheological behaviour (between 5 and 20s(-1)) of a 5% (w/w) viscoelastic gum extracted from the fronds of the native New Zealand black tree fern or mamaku in Māori was further explored by manipulating the salt content. The freeze-dried mamaku gum contained a high mineral content and sugars which upon removal via dialysis, resulted in the loss of shear thickening. However, this loss was reversible by the addition of salts to the dialysed dispersion. The mechanism of shear-thickening behaviour was therefore hypothesised to be due to shear-induced transition of intra- to intermolecular hydrogen bonding, promoted by the screening effect of cations. Mono-, di- and trivalent salts, i.e. Na(+), K(+), N(CH3)4(+), Ca(2+), Mg(2+), Al(3+) and La(3+) at concentrations between 0.001 and 1.0M were tested to support the hypothesis as well as to demonstrate the sensitivity of the biopolymer to cation valency and concentrations. The cation valency and concentration were crucial factors in determining: (i) zero-shear viscosity, (ii) critical shear rate, γ˙c (or shear rate at the onset of shear-thickening) and (iii) the extent of shear-thickening of the solution. For mono- and divalent cations these parameters were similar at equivalent ionic strengths and fairly independent of the cation type. Trivalent cations (La(3+)) however caused precipitation of the gum in the concentration range of 0.005-0.05 M but clear dispersions were obtained above 0.05 M.
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Abstract Text: Oil-in-water emulsions are an important basis of many food products such as soup, sauces, salad dressing, processed cheese and whipped cream. In many cases, liquid emulsions are processed at high temperature (e.g., retort... more
Abstract Text: Oil-in-water emulsions are an important basis of many food products such as soup, sauces, salad dressing, processed cheese and whipped cream. In many cases, liquid emulsions are processed at high temperature (e.g., retort or UHT processing) and maybe stored at different temperatures. There is little information on how high heat treatment and storage temperatures influence the creaming stability of caseinate-stabilized emulsions. In this study, we investigated the effects of heating and storage conditions on the structural, mechanical and rheological properties of caseinate-stabilized emulsions. The stock emulsion was prepared by mixing a reconstituted sodium caseinate solution (2% w/w) with 60% w/w oil and subjecting it to a high pressure homogenization. Caseinate solutions of different concentration were heated separately at 120 °C as a function of time up to 60 min. These heated caseinate solutions were then mixed with the stock emulsion in different ratios to form ...
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Dietary fibres, particularly viscous fibres appear to be more effective for appetite control (reduce subjective appetite, energy intake and/or body weight). Three types of viscous fibres, pectin, alginate and cereal beta-glucan, were... more
Dietary fibres, particularly viscous fibres appear to be more effective for appetite control (reduce subjective appetite, energy intake and/or body weight). Three types of viscous fibres, pectin, alginate and cereal beta-glucan, were identified as potential satiety-enhancing ingredients. The aim of this review was to collect evidence from human intervention studies evaluating pectins, alginates and beta-glucans in beverages, liquid preloads and liquid test meals for their satiety effects. Our focused, narrative review of several satiety studies shows an overall consistent result on the effectiveness of pectin, alginate and beta-glucan for appetite control. Beverages or liquid test meals are probably the better delivery mode for these fibres, as their effect on satiety is affected by their physico-chemical properties. Most, if not all, of these reviewed studies gave little or no consideration to the potential effects of common food processing (e.g. pasteurisation, ultra-high temperature process) on the physico-chemical properties of these fibre-containing beverages. This is one of the research gaps we have identified warranting further work, which is likely to be of significance from the industry and consumer perspective.
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Flow behaviour of Basil seed gum (BSG) as a new source of food hydrocolloids in combinations with Locust bean gum (LBG) and Guar gum (GG) were studied using a controlled stress rheometer at 0.01-1000 (1/s) and 20 °C. The time independent... more
Flow behaviour of Basil seed gum (BSG) as a new source of food hydrocolloids in combinations with Locust bean gum (LBG) and Guar gum (GG) were studied using a controlled stress rheometer at 0.01-1000 (1/s) and 20 °C. The time independent rheological models, Cross and Carreau, showed the best fitting results with flow behaviour data of all mixtures. Flow behaviour index (n) of BSG measured higher than GG and LBG, respectively. The 40-60 and 20-80 mixtures of BSG-GG had the highest and the lowest shear thinning behaviour, respectively. However, 20-80 mixture of BSG-LBG showed the lowest deviation from Newtonian behaviour among other mixtures of BSG-LBG. As BSG exhibited higher zero shear viscosity than GG and LBG (around 200 and 1400 times of zero shear viscosity of GG and LBG, respectively), mixing BSG with GG and LBG led to increase zero shear viscosity of mixtures. Increasing the ratio of BSG in gum mixtures were caused structure breakdown and intensified time dependency (Thixotrop...
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The interpretation of milk X-ray and neutron scattering data in relation to the internal structure of the casein micelle is an ongoing debate. We performed resonant X-ray scattering measurements on liquid milk and conclusively identified... more
The interpretation of milk X-ray and neutron scattering data in relation to the internal structure of the casein micelle is an ongoing debate. We performed resonant X-ray scattering measurements on liquid milk and conclusively identified key scattering features, namely those corresponding to the size of and the distance between colloidal calcium phosphate particles. An X-ray scattering feature commonly assigned to the particle size is instead due to protein inhomogeneities.
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ABSTRACT An anti-solvent precipitation technique was explored for the ability to produce lignin microparticles. An aqueous–organic solution of lignin was dispersed into a much larger volume of water, whereby leaching of organic solvent... more
ABSTRACT An anti-solvent precipitation technique was explored for the ability to produce lignin microparticles. An aqueous–organic solution of lignin was dispersed into a much larger volume of water, whereby leaching of organic solvent from the dispersed phase into the water resulted in progressive precipitation of the lignin solute, ultimately producing a suspension of hardened microparticles. Temperature and addition of surfactant were investigated as a means of controlling particle properties. Increasing initial water temperature between 4 and 80 °C produced increasingly large agglomerates of uniform sub-micron primary particles, increasingly fused into monolithic masses. Although the glass transition temperatures of dried lignins were in the range of 75–87 °C, depression of glass transition temperature in the presence of water during particle formation may be associated with the increasing agglomeration of particles with increasing temperature. Incorporating sodium dodecyl sulfate (SDS) in the water at temperatures of 20–60 °C inhibited agglomeration producing smooth, spherical, monodisperse particles in the range of 0.1–0.2 μm. However, SDS concentrations greater than 1% caused the formation of some larger particles. Once safety, consumer acceptance and aspects of functionality have been established, spherical particles in the 0.1–0.2 μm size range may have application as food industry fat mimetics, fillers or even as solid particle emulsifiers. Industrial relevance Increased biorefining of lignocellulosic feedstocks to produce bioethanol may lead to an abundance of lignin that could be well-utilised as a sustainable, non-caloric food ingredient. Microparticulation provides a route for the transformation of lignin into a useful food ingredient, on the basis that particles with suitable properties for use in food systems can be produced: notably, a particle diameter preferably between 0.1 and 25 μm, spherical shape and stability against aggregation.
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... Sudhakar et al. ... Korus et al. [19], and Sidhu and Bawa [20] con-firmed lower SB of triticale starch and wheat flour pasted with arabic gum, respectively. Both guar gum and LBG increased BD and SB considerably in all treatments.... more
... Sudhakar et al. ... Korus et al. [19], and Sidhu and Bawa [20] con-firmed lower SB of triticale starch and wheat flour pasted with arabic gum, respectively. Both guar gum and LBG increased BD and SB considerably in all treatments. Rojas et al. ...