Mamaku gum, extracted from the New Zealand Black Tree Fern can affect in vitro gastrointestinal e... more Mamaku gum, extracted from the New Zealand Black Tree Fern can affect in vitro gastrointestinal enzyme activity and colonic fermentation.
We examined the effect of gavage of 4 ml of a viscous shear-thickening polysaccharide solution (1... more We examined the effect of gavage of 4 ml of a viscous shear-thickening polysaccharide solution (15% w/w) extracted from the fronds of the mamaku tree fern (Cythea medullaris) in reducing appetite and delaying gastric emptying in twenty six Sprague Dawley rats.
This study focuses on understanding the effect of ionic strength on the mechanical and microstruc... 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....
White bread contains a high proportion of easily digestible starch, which contributes to an undes... 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...
Abstract This study focuses on the rheological characterization of the time- and shear-dependence... more Abstract This study focuses on the rheological characterization of the time- and shear-dependence of a physically modified waxy potato starch through treatment at 120 °C for 30 min under continuous stirring. The starch sample exhibited time-dependency, where the viscosity increased with time at constant shear rates between 5 and 60 s-1. Shear-induced gelation was also observed when the sample was sheared above 100 s-1. The gel structure remained relatively stable within the experimental timeframe of 72 h at 20 °C. A minimum starch concentration of 1 % w/w was required for shear-thickening and anti-thixotropy to be observed. This study showed that the formation of a shear-induced weak gel structure was not caused solely by hydrogen bonding, electrostatic, hydrophobic interactions or a combination of these forces. The formation of a weak gel structure was probably initiated first by shear which orientated the amylopectin molecules in the direction of shear. The ‘stretched’ amylopectin molecules subsequently facilitated closer proximity between polymer chains which promoted intermolecular association between polymer chains to take place.
Abstract This study focuses on the physico-chemical properties of a “clean-label” modified starch... more Abstract This study focuses on the physico-chemical properties of a “clean-label” modified starch (de-structured starch) as a potential food ingredient. The modified starch was obtained by the disassembly of native waxy potato starch granules into its macromolecular chains. Waxy potato starch samples were treated at elevated temperatures of 120, 130, 140, and 150 °C for 30 min at a stirring speed of 300 rpm in a high pressure reactor. Starch treated at 120 °C showed similar molar mass as its native form indicating that treatment at 120 °C had resulted in the disassembly of the starch granules into its macromolecular chains. Reduction in viscosity and particle size was observed with increased temperature from 120 to 150 °C. The reduction in viscosity and size was not only attributed to the disassembly of starch granules into its macromolecular fractions but also due to a further size reduction of amylopectin chains. De-structured starch treated at 140 and 150 °C exhibited flow behavior approaching Newtonian fluid. However, de-structured starch treated at 120 and 130 °C exhibited shear-thickening behavior above their critical shear rates at 14 and 27 s−1 respectively. Shear-induced interactions among starch macromolecular fractions appeared to have occurred within a narrow range of heat treatment (120 and 130 °C) but not in more severely heat-treated starches (140 and 150 °C).
Rice starch is a common functional ingredient used in various food applications. The drying regim... more Rice starch is a common functional ingredient used in various food applications. The drying regime to obtain dry starch powder is an important processing step, which affects the functional properties of the starch. The application of extreme thermal treatment during the conventional drying process tends to elicit irreversible changes to the rice starch, resulting in the loss of desired functionalities. In a previous study, we reported the development of a novel low temperature spray-drying based process which efficiently dries waxy rice starch, while preserving its physicochemical properties and functionalities. This study, a follow-up to the previous report, evaluated the effect of different spray-drying inlet temperatures on the production yield, physicochemical properties, and functionalities of waxy rice starch. Increasing the inlet temperature from 40 °C to 100 °C resulted in an increase in the process yield from 74.83% to 88.66%, respectively. All spray dried waxy rice starche...
The digestibility of wheat starch gels in the presence of Mesona chinensis polysaccharide (MCP) w... more The digestibility of wheat starch gels in the presence of Mesona chinensis polysaccharide (MCP) was studied.
Mamaku gum, extracted from the New Zealand Black Tree Fern can affect in vitro gastrointestinal e... more Mamaku gum, extracted from the New Zealand Black Tree Fern can affect in vitro gastrointestinal enzyme activity and colonic fermentation.
We examined the effect of gavage of 4 ml of a viscous shear-thickening polysaccharide solution (1... more We examined the effect of gavage of 4 ml of a viscous shear-thickening polysaccharide solution (15% w/w) extracted from the fronds of the mamaku tree fern (Cythea medullaris) in reducing appetite and delaying gastric emptying in twenty six Sprague Dawley rats.
This study focuses on understanding the effect of ionic strength on the mechanical and microstruc... 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....
White bread contains a high proportion of easily digestible starch, which contributes to an undes... 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...
Abstract This study focuses on the rheological characterization of the time- and shear-dependence... more Abstract This study focuses on the rheological characterization of the time- and shear-dependence of a physically modified waxy potato starch through treatment at 120 °C for 30 min under continuous stirring. The starch sample exhibited time-dependency, where the viscosity increased with time at constant shear rates between 5 and 60 s-1. Shear-induced gelation was also observed when the sample was sheared above 100 s-1. The gel structure remained relatively stable within the experimental timeframe of 72 h at 20 °C. A minimum starch concentration of 1 % w/w was required for shear-thickening and anti-thixotropy to be observed. This study showed that the formation of a shear-induced weak gel structure was not caused solely by hydrogen bonding, electrostatic, hydrophobic interactions or a combination of these forces. The formation of a weak gel structure was probably initiated first by shear which orientated the amylopectin molecules in the direction of shear. The ‘stretched’ amylopectin molecules subsequently facilitated closer proximity between polymer chains which promoted intermolecular association between polymer chains to take place.
Abstract This study focuses on the physico-chemical properties of a “clean-label” modified starch... more Abstract This study focuses on the physico-chemical properties of a “clean-label” modified starch (de-structured starch) as a potential food ingredient. The modified starch was obtained by the disassembly of native waxy potato starch granules into its macromolecular chains. Waxy potato starch samples were treated at elevated temperatures of 120, 130, 140, and 150 °C for 30 min at a stirring speed of 300 rpm in a high pressure reactor. Starch treated at 120 °C showed similar molar mass as its native form indicating that treatment at 120 °C had resulted in the disassembly of the starch granules into its macromolecular chains. Reduction in viscosity and particle size was observed with increased temperature from 120 to 150 °C. The reduction in viscosity and size was not only attributed to the disassembly of starch granules into its macromolecular fractions but also due to a further size reduction of amylopectin chains. De-structured starch treated at 140 and 150 °C exhibited flow behavior approaching Newtonian fluid. However, de-structured starch treated at 120 and 130 °C exhibited shear-thickening behavior above their critical shear rates at 14 and 27 s−1 respectively. Shear-induced interactions among starch macromolecular fractions appeared to have occurred within a narrow range of heat treatment (120 and 130 °C) but not in more severely heat-treated starches (140 and 150 °C).
Rice starch is a common functional ingredient used in various food applications. The drying regim... more Rice starch is a common functional ingredient used in various food applications. The drying regime to obtain dry starch powder is an important processing step, which affects the functional properties of the starch. The application of extreme thermal treatment during the conventional drying process tends to elicit irreversible changes to the rice starch, resulting in the loss of desired functionalities. In a previous study, we reported the development of a novel low temperature spray-drying based process which efficiently dries waxy rice starch, while preserving its physicochemical properties and functionalities. This study, a follow-up to the previous report, evaluated the effect of different spray-drying inlet temperatures on the production yield, physicochemical properties, and functionalities of waxy rice starch. Increasing the inlet temperature from 40 °C to 100 °C resulted in an increase in the process yield from 74.83% to 88.66%, respectively. All spray dried waxy rice starche...
The digestibility of wheat starch gels in the presence of Mesona chinensis polysaccharide (MCP) w... more The digestibility of wheat starch gels in the presence of Mesona chinensis polysaccharide (MCP) was studied.
Uploads
Papers