Changes in protein and fat globules during dynamic gastric digestion of mammalian milks in the hu... more Changes in protein and fat globules during dynamic gastric digestion of mammalian milks in the human gastric simulator at different digestion times.
Dietary fats and oils are an important component of our diet and a significant contributor to tot... more Dietary fats and oils are an important component of our diet and a significant contributor to total energy and intake of lipophilic nutrients and bioactives. We discuss their fate in a wide variety of engineered, processed and naturally-occurring foods as they pass through the gastrointestinal tract and the implicit role of the food matrix within which they reside. Important factors that control fat and oil digestion include: 1) Their physical state (liquid or solid); 2) Dispersion of oil as emulsion droplets and control of the interfacial structure of emulsified oils; 3) The structure and rheology of the food matrix surrounding dispersed oil droplets; and 4) Alteration of emulsified oil droplet size and concentration. Using examples based on model foods such as emulsion gels and everyday foods such as almonds and cheese, we demonstrate that food structure design may be used as a tool to modulate fat and oil digestion potentially resulting in a number of targeted physiological outco...
This study explored the interactions of orthophosphate with casein-iron precipitates. Casein-iron... more This study explored the interactions of orthophosphate with casein-iron precipitates. Casein-iron precipitates were formed by adding ferric chloride at ≥10mM to sodium caseinate solutions ranging in concentration from 1 to 3%(w/v). The addition of different concentrations of orthophosphate solution to the casein-iron precipitates resulted in gradual adsorption of the orthophosphate, causing re-dispersion of the casein-iron complexes. The interactions of added orthophosphate with iron in the presence and absence of caseins are postulated, and new mechanisms are proposed. The re-dispersed soluble complexes of casein-iron-orthophosphate generated using this process could be used as novel iron fortificants.
The effects of cholesterol and lactoferrin on the kinetic stability and membrane structural integ... more The effects of cholesterol and lactoferrin on the kinetic stability and membrane structural integrity of negatively charged liposomes under in vitro infant intestinal digestion conditions were elucidated using dynamic light scattering, pH-stat titration, Fourier transform infrared spectroscopy, and pyrene steady state fluorescence probes. The liposomes had a smaller particle diameter, a wider size distribution, and a greater negative charge after digestion. The incorporation of cholesterol into the phospholipid bilayers resulted in a more ordered conformation in the aliphatic tail region and reduced micropolarity, indicating that cholesterol can improve the structural stability of liposomal membranes against intestinal environmental stress. Lactoferrin coverage facilitated the release of free fatty acids and increased the microfluidity of the bilayers, reducing the structural integrity of the liposomes. This study provides useful information on the design of liposomes and other micr...
The behaviour of milk fat globules in the coagula of unheated and heated (90 °C for 20 min) whole... more The behaviour of milk fat globules in the coagula of unheated and heated (90 °C for 20 min) whole milk during gastric digestion was investigated using a human gastric simulator.
In this study, liposomes (LPs), chitosan (CH) coated LPs, sodium alginate (AL) and CH multilayere... more In this study, liposomes (LPs), chitosan (CH) coated LPs, sodium alginate (AL) and CH multilayered LPs (AL-CH-LPs) were developed based on the electrostatic interaction between charged polysaccharides at a certain pH. The increase of polymer layers on LPs led to a monotonic increase in size from ∼600 (LPs) to ∼1810nm (AL-CH-LPs) and negative charge from -12.5 to -25.2mV, regarded as a consequence of the formation of gradually expanded structures by cationic CH and anionic AL. The environmental stress including pH, storage and ionic strength (10-200mM NaCl) had significant impact on the appearance and the particle size of the double-layered liposome (AL-CH-LPs). Furthermore, LPs showed the highest release rate of hydrophilic model ingredient (vitamin C) under gastrointestinal conditions, while the polymers had a capacity to reduce the vitamin C release in simulated intestinal fluid. This work provided useful information on the potential application of CH and AL based delivery systems.
Changes in protein and fat globules during dynamic gastric digestion of mammalian milks in the hu... more Changes in protein and fat globules during dynamic gastric digestion of mammalian milks in the human gastric simulator at different digestion times.
Dietary fats and oils are an important component of our diet and a significant contributor to tot... more Dietary fats and oils are an important component of our diet and a significant contributor to total energy and intake of lipophilic nutrients and bioactives. We discuss their fate in a wide variety of engineered, processed and naturally-occurring foods as they pass through the gastrointestinal tract and the implicit role of the food matrix within which they reside. Important factors that control fat and oil digestion include: 1) Their physical state (liquid or solid); 2) Dispersion of oil as emulsion droplets and control of the interfacial structure of emulsified oils; 3) The structure and rheology of the food matrix surrounding dispersed oil droplets; and 4) Alteration of emulsified oil droplet size and concentration. Using examples based on model foods such as emulsion gels and everyday foods such as almonds and cheese, we demonstrate that food structure design may be used as a tool to modulate fat and oil digestion potentially resulting in a number of targeted physiological outco...
This study explored the interactions of orthophosphate with casein-iron precipitates. Casein-iron... more This study explored the interactions of orthophosphate with casein-iron precipitates. Casein-iron precipitates were formed by adding ferric chloride at ≥10mM to sodium caseinate solutions ranging in concentration from 1 to 3%(w/v). The addition of different concentrations of orthophosphate solution to the casein-iron precipitates resulted in gradual adsorption of the orthophosphate, causing re-dispersion of the casein-iron complexes. The interactions of added orthophosphate with iron in the presence and absence of caseins are postulated, and new mechanisms are proposed. The re-dispersed soluble complexes of casein-iron-orthophosphate generated using this process could be used as novel iron fortificants.
The effects of cholesterol and lactoferrin on the kinetic stability and membrane structural integ... more The effects of cholesterol and lactoferrin on the kinetic stability and membrane structural integrity of negatively charged liposomes under in vitro infant intestinal digestion conditions were elucidated using dynamic light scattering, pH-stat titration, Fourier transform infrared spectroscopy, and pyrene steady state fluorescence probes. The liposomes had a smaller particle diameter, a wider size distribution, and a greater negative charge after digestion. The incorporation of cholesterol into the phospholipid bilayers resulted in a more ordered conformation in the aliphatic tail region and reduced micropolarity, indicating that cholesterol can improve the structural stability of liposomal membranes against intestinal environmental stress. Lactoferrin coverage facilitated the release of free fatty acids and increased the microfluidity of the bilayers, reducing the structural integrity of the liposomes. This study provides useful information on the design of liposomes and other micr...
The behaviour of milk fat globules in the coagula of unheated and heated (90 °C for 20 min) whole... more The behaviour of milk fat globules in the coagula of unheated and heated (90 °C for 20 min) whole milk during gastric digestion was investigated using a human gastric simulator.
In this study, liposomes (LPs), chitosan (CH) coated LPs, sodium alginate (AL) and CH multilayere... more In this study, liposomes (LPs), chitosan (CH) coated LPs, sodium alginate (AL) and CH multilayered LPs (AL-CH-LPs) were developed based on the electrostatic interaction between charged polysaccharides at a certain pH. The increase of polymer layers on LPs led to a monotonic increase in size from ∼600 (LPs) to ∼1810nm (AL-CH-LPs) and negative charge from -12.5 to -25.2mV, regarded as a consequence of the formation of gradually expanded structures by cationic CH and anionic AL. The environmental stress including pH, storage and ionic strength (10-200mM NaCl) had significant impact on the appearance and the particle size of the double-layered liposome (AL-CH-LPs). Furthermore, LPs showed the highest release rate of hydrophilic model ingredient (vitamin C) under gastrointestinal conditions, while the polymers had a capacity to reduce the vitamin C release in simulated intestinal fluid. This work provided useful information on the potential application of CH and AL based delivery systems.
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