John Antoniou | Jiangnan University (original) (raw)
Papers by John Antoniou
Advance Journal of Food Science and Technology, 2015
Microencapsulation is a promising technique to retain the physical attributes of nanoemulsions an... more Microencapsulation is a promising technique to retain the physical attributes of nanoemulsions and to overcome the oxidation of bioactives that become more available to aqueous phase during emulsification. Purity Gum Ultra (PGU) and Hi-CAP 100 (HiCap) emulsified nanoemulsions of Clove Oil (CO) co-encapsulated with Canola oil (CA) and Medium Chain Triglyceride (MCT) (5:5% v/v CO:CA and CO:MCT) were prepared through high pressure homogenization. Microencapsulation of nanoemulsions was performed using Whey Protein Isolates (WPI) under vacuum using freeze drying, which is considered as appropriate method for heat sensitive compounds. The reconstituted emulsions of microencapsulated powder had similar particle sizes as that of fresh nanoemulsions while uncoated showed a big increase (<400 nm). Oxidation of bioactives with and without CO, before and after freeze drying was investigated at different intervals during 60 days of storage at 4 and 25°C by Thiobarbituric Acid Reactive Substances (TBARS) assay. Microencapsulated PGU-CO:CA showed minimum TBARS values compared to other emulsions. Gas chromatography analysis of microcapsules also showed higher retention of CO and lower content on the interphase for aqueous interaction. Conclusively, this study proposes a novel strategy using a freeze drying process to microencapsulate nanoemulsion.
Archives of microbiology, 2015
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions showed memb...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
Chitosan-tripolyphosphate nanoparticles were prepared through ionic-crosslinking. Control of ... more Chitosan-tripolyphosphate nanoparticles were prepared through ionic-crosslinking. Control of particle size by selecting appropriate conditions. Influence of initial pH and salinity of chitosan solution on nanoparticles formation. Separation of aggregates from nanoparticles by centrifugation. Ultra-sonication reduced particle size but caused fragmentation on their structure.
Food Hydrocolloids
ABSTRACT The aim of this work was to evaluate the effect of sodium acetate (NaOAc) on the physico... more ABSTRACT The aim of this work was to evaluate the effect of sodium acetate (NaOAc) on the physicochemical properties of gelatin films with different leveling of triple helical structure. Films were obtained by casting method and dried at two temperatures (25 and 35 °C). Drying at 25 °C improved physical properties and increased the formation content of triple helix. The plasticizing effect of NaOAc was shown from typical stress–strain curves with the features of ductile materials. Dynamic mechanical thermal analysis (DMTA) also confirmed the thermomechanical properties of the films and revealed the decrease of glass transition temperature (Tg) with increasing NaOAc content. The increase of moisture content or decrease in intermolecular forces because of the existence of NaOAc might be attributed to the plasticizing effect. Films with NaOAc showed a higher capacity to absorb water compared to those without NaOAc at higher relative humidity (75% and 97%). All these gelatin films exhibited dominant elastic behavior (than viscous behavior) over the entire frequency range (0.1–100 Hz) at any loading content of NaOAc but the compactness of films was changed. X-ray diffraction (XRD) and water contact angle (WCA) revealed that the NaOAc crystals were dissolved in the gelatin matrix. These results may cause the extensive concern for the effects of salts (organic or inorganic) on films because salts exist widely.
Asian Pacific Journal of Cancer Prevention, 2014
Carbohydrate polymers, Sep 20, 2016
The oxidative stability of (-)-epigallocatechin-3-gallate (EGCG) incorporated as inclusion comple... more The oxidative stability of (-)-epigallocatechin-3-gallate (EGCG) incorporated as inclusion complexes (ICs) in sulfobutylether-β-cyclodextrin sodium (SBE-β-CD) and then ionotropically crosslinked with chitosan hydrochloride (CSH) into nanoparticles were investigated. EGCG-loaded CSH-SBE-β-CD nanoparticles (CSNs) were physically unstable at higher pH and temperature. The particle size of CSNs was unchanged in the pH range of 3-5, but the microenvironment of EGCG-IC appeared to be intact until the pH increased to 6.5 by fluorescence spectroscopy. The physical structure of EGCG-ICs was also affected during storage in addition to CSNs, which was further affected as temperature increased from 25 to 55°C. The decrease in antioxidant activities of EGCG-ICs and free EGCG with increasing pH, storage time and temperature were modest compared to the prominent decreases in antioxidant activities of EGCG-loaded CSNs. The extreme entrapment of EGCG-ICs and/or free EGCG in the aggregated CSNs restr...
Food Hydrocolloids, 2015
Abstract Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosa... more Abstract Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanoparticles at various concentrations. The composites films were compared in terms of antimicrobial activity, thermomechanical, physicochemical and barrier properties. The thermal stability of the films was studied using thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements were used to study the interactions and compatibility between the polysaccharides with in the films. The microstructure of the films was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Incorporation of chitosan nanoparticles improved mechanical, physicochemical and barrier properties. Tensile strength was increased by 35.73 MPa while the elongation was decreased by 7.21%. Water solubility and water vapor permeability (WVP) were reduced by 74.3% and 22.7%, respectively. The compact structure of the chitosan nanoparticles reduced the free volume of the polymer matrix more than bulk chitosan by obstructing the diffusion of water and thereby decreasing the moisture content of the films. Additionally, the microstructure of the films showed that the nanoparticles were distributed homogenously with in the structure and increased the roughness of the surface. However, tara gum films with bulk chitosan exhibited better antimicrobial activity. Incorporation of chitosan nanoparticles produced films less effective against Escherichia coli compared to Staphylococcus aureus, and their antimicrobial activity was reduced at high concentrations probably due to agglomeration.
Food Hydrocolloids, 2015
ABSTRACT Consumption of essential oils (EOs) and their components, such as eugenol (EU) may reduc... more ABSTRACT Consumption of essential oils (EOs) and their components, such as eugenol (EU) may reduce chronic disorders, but their use in food is currently limited because of poor solubility and low bioavailability. The aim of this work was to study the influence of carrier oil type, particle size on in vitro lipid digestion and EU release using canola (LCT) and MCT oil-in- 3 water emulsions with different droplet diameters (Coarse > 3000 nm , NE1 > 300 nm and 3 NE2 > 150 nm). There was a progressive increase in the mean particle size of coarse emulsions of both LCT & MCT oils as they passed through simulated gastrointestinal tract consisting of mouth, stomach and intestine phases, which was due to droplet coalescence, flocculation and digestion. However, NE1 and NE2 nanoemulsions showed appreciable increase in particle size after exposure to the simulated intestinal fluid. The rate and extent of in vitro lipid digestion increased with decreasing mean droplet diameter (NE2 ≈ NE1 » 4 Coarse) in both MCT & LCT emulsions. However, MCT emulsions showed faster rate of in vitro lipid digestion which was attributed to more exposure of droplets with the lipase. There 4 was also an appreciable increase in release percentage of eugenol with decreasing droplet diameter (NE2 > NE1 > Coarse) and it was higher in LCT (84%) emulsions which was attributed to large hydrophobic cores that better solubilize EU.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
Abstract Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last de... more Abstract Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade because of their numerous applications. In this study, we describe conditions to optimize chitosan nanoparticles as potential nano-fillers in edible films. The ionic cross-linking between the cationic amino groups on the chitosan (CS) chain and the anionic phosphate groups of sodium tripolyphosphate (TPP) was verified via FTIR. Particle size, polydispersity index (PDI) and surface ζ-potential were controlled by chitosan's Mw and concentration, CS:TPP mass ratio, and external conditions such as pH and salinity of the initial chitosan solution. Post-processing methods such as centrifugation and ultra-sonication were used to further control particle size. We show that particle size can be controlled by selecting appropriate conditions. Particles with sizes below 120 nm were produced at different CS:TPP mass ratios depending on the CS concentration. Dilute NaCl was the optimal solution ionic composition that decreased the size by 25% and also resulted in a narrow particle size distribution. We show using UV–vis spectrophotometry that particles of different size, separated by centrifugation had different phosphorus content. Ultra-sonication can be used to reduce the size by 50% but long time caused fragmentation of the nanoparticles. Transmission electron microscopy (TEM) revealed the differences in the morphology of chitosan nanoparticles under various fabrication conditions.
In this study eugenol (EU) loaded nanoemulsions (NEs) emulsified with modified starch were prepar... more In this study eugenol (EU) loaded nanoemulsions (NEs) emulsified with modified starch were prepared and their apoptotic potential against liver and colon cancer cells was examined in comparison with bulk EU. Materials and Methods: We prepared stable EU loaded NEs whcih were characterized by dynamic light scattering, centrifugation and gas chromatography. Furthermore, cell viability was determined using MTT
assay, and apoptosis and cell cycle analysess by flow cytometry. Results: HB8065 (liver) and HTB37 (colon) cells when treated with EU:CA NEs demonstrated greater apoptotic cells percentages as evidenced by microscopic images and flow cytometric evaluations. It was observed that EU and EU:CA NE induced apoptosis in both cell lines via reactive oxygen species (ROS) generation. Conclusions: The present study demonstrated that ROS plays a critical role in EU and EU:CA NE induced apoptosis.
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum
effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions.
Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade beca... more Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade because of their numerous applications. In this study, we describe conditions to optimize chitosan nanoparticles
as potential nano-fillers in edible films. The ionic cross-linking between the cationic amino groups on the chitosan (CS) chain and the anionic phosphate groups of sodium tripolyphosphate (TPP) was verified via
FTIR. Particle size, polydispersity index (PDI) and surface -potential were controlled by chitosan’s Mw and concentration, CS:TPP mass ratio, and external conditions such as pH and salinity of the initial chitosan solution. Post-processing methods such as centrifugation and ultra-sonication were used to further control particle size. We show that particle size can be controlled by selecting appropriate conditions.
Particles with sizes below 120 nm were produced at different CS:TPP mass ratios depending on the CS concentration. Dilute NaCl was the optimal solution ionic composition that decreased the size by 25% and
also resulted in a narrow particle size distribution. We show using UV–vis spectrophotometry that particles of different size, separated by centrifugation had different phosphorus content. Ultra-sonication can
be used to reduce the size by 50% but long time caused fragmentation of the nanoparticles. Transmission electron microscopy (TEM) revealed the differences in the morphology of chitosan nanoparticles under
various fabrication conditions.
Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanopar... more Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanoparticles at various concentrations. The composites films were compared in terms of antimicrobial activity, thermomechanical, physicochemical and barrier properties. The thermal stability of the films was studied using thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements were used to study the interactions and compatibility between the polysaccharides with in the films. The microstructure of the films was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Incorporation of chitosan nanoparticles improved mechanical, physicochemical and barrier properties. Tensile strength was increased by 35.73 MPa while the elongation was decreased by 7.21%. Water solubility and water vapor permeability (WVP) were reduced by 74.3% and 22.7%, respectively. The compact structure of the chitosan nano-particles reduced the free volume of the polymer matrix more than bulk chitosan by obstructing the diffusion of water and thereby decreasing the moisture content of the films. Additionally, the micro-structure of the films showed that the nanoparticles were distributed homogenously with in the structure and increased the roughness of the surface. However, tara gum films with bulk chitosan exhibited better antimicrobial activity. Incorporation of chitosan nanoparticles produced films less effective against Escherichia coli compared to Staphylococcus aureus, and their antimicrobial activity was reduced at high concentrations probably due to agglomeration.
Journal of agricultural and food chemistry, Jan 31, 2015
Gelatin films incorporated with chitosan nanoparticles of various free/encapsulated tea polypheno... more Gelatin films incorporated with chitosan nanoparticles of various free/encapsulated tea polyphenols (TP) ratios were prepared in order to investigate the influence of different ratios on physico-chemical and antioxidant properties of films. The TP containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutylether-β-cyclodextrin sodium (SBE-β-CD) at three different encapsulation efficiencies (EE, ~50%, ~80% and ~100%) of TP. The stability of TP-loaded nanoparticles was maintained during film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflow...
Archives of microbiology, 2015
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions showed memb...
Carbohydrate Polymers, 2014
The aim of this study was to evaluate tara gum as edible film material as well as the influence o... more The aim of this study was to evaluate tara gum as edible film material as well as the influence of polyols as plasticizers on the properties of the films. Thermomechanical, physicochemical and barrier properties were determined as a function of plasticizer type and concentration. Glycerol, sorbitol and PEG 400 were used in the range of 0.075-0.3g/tarag. Glycerol was the best plasticizer in terms of mechanical properties with the highest elongation (16-44%) and resistance (45-90 MPa). Sorbitol presented the best barrier properties with the lowest hydrophilicity and water vapour permeability (0.24-0.34 g mm m(-2)h(-1) kPa(-1)). Fourier transform infrared (FTIR) spectroscopy showed no significant effect on the structure of the polysaccharide. Dynamic mechanical analysis (DMA) revealed that incorporation of plasticizers increased the mobility of the polymer chains and reduced the glass transition and melting temperature by 30 and 100 °C respectively.
Food Chemistry, 2014
The objective of this study was to analyze the influence of thermal-acid treatment on the formati... more The objective of this study was to analyze the influence of thermal-acid treatment on the formation of resistant starch (RS). The maximum RS content in citric acid-heat treated starches (CAHT) reached 36.55%, which was 7 times higher of that in native starch. According to HPSEC-MALLS-RI analysis, amylopectin was more susceptible to hydrolysis than amylose during citric acid-heat treatment (CAH). X-ray measurement revealed that even though the starch crystalline pattern was changed from A-type to a more resistant B-type after CAH, the fraction of crystalline region decreased from 21.16% to 8.37%. The hydroxyls on the starch chains were substituted by the citric acid anhydrides during CAH according to FT-IR analysis, which led to the formation of ester bond cross-linking structures in starch granules, and it could be the main contribution to the increase of RS content in CAHT samples.
Advance Journal of Food Science and Technology, 2015
Microencapsulation is a promising technique to retain the physical attributes of nanoemulsions an... more Microencapsulation is a promising technique to retain the physical attributes of nanoemulsions and to overcome the oxidation of bioactives that become more available to aqueous phase during emulsification. Purity Gum Ultra (PGU) and Hi-CAP 100 (HiCap) emulsified nanoemulsions of Clove Oil (CO) co-encapsulated with Canola oil (CA) and Medium Chain Triglyceride (MCT) (5:5% v/v CO:CA and CO:MCT) were prepared through high pressure homogenization. Microencapsulation of nanoemulsions was performed using Whey Protein Isolates (WPI) under vacuum using freeze drying, which is considered as appropriate method for heat sensitive compounds. The reconstituted emulsions of microencapsulated powder had similar particle sizes as that of fresh nanoemulsions while uncoated showed a big increase (<400 nm). Oxidation of bioactives with and without CO, before and after freeze drying was investigated at different intervals during 60 days of storage at 4 and 25°C by Thiobarbituric Acid Reactive Substances (TBARS) assay. Microencapsulated PGU-CO:CA showed minimum TBARS values compared to other emulsions. Gas chromatography analysis of microcapsules also showed higher retention of CO and lower content on the interphase for aqueous interaction. Conclusively, this study proposes a novel strategy using a freeze drying process to microencapsulate nanoemulsion.
Archives of microbiology, 2015
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions showed memb...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
Chitosan-tripolyphosphate nanoparticles were prepared through ionic-crosslinking. Control of ... more Chitosan-tripolyphosphate nanoparticles were prepared through ionic-crosslinking. Control of particle size by selecting appropriate conditions. Influence of initial pH and salinity of chitosan solution on nanoparticles formation. Separation of aggregates from nanoparticles by centrifugation. Ultra-sonication reduced particle size but caused fragmentation on their structure.
Food Hydrocolloids
ABSTRACT The aim of this work was to evaluate the effect of sodium acetate (NaOAc) on the physico... more ABSTRACT The aim of this work was to evaluate the effect of sodium acetate (NaOAc) on the physicochemical properties of gelatin films with different leveling of triple helical structure. Films were obtained by casting method and dried at two temperatures (25 and 35 °C). Drying at 25 °C improved physical properties and increased the formation content of triple helix. The plasticizing effect of NaOAc was shown from typical stress–strain curves with the features of ductile materials. Dynamic mechanical thermal analysis (DMTA) also confirmed the thermomechanical properties of the films and revealed the decrease of glass transition temperature (Tg) with increasing NaOAc content. The increase of moisture content or decrease in intermolecular forces because of the existence of NaOAc might be attributed to the plasticizing effect. Films with NaOAc showed a higher capacity to absorb water compared to those without NaOAc at higher relative humidity (75% and 97%). All these gelatin films exhibited dominant elastic behavior (than viscous behavior) over the entire frequency range (0.1–100 Hz) at any loading content of NaOAc but the compactness of films was changed. X-ray diffraction (XRD) and water contact angle (WCA) revealed that the NaOAc crystals were dissolved in the gelatin matrix. These results may cause the extensive concern for the effects of salts (organic or inorganic) on films because salts exist widely.
Asian Pacific Journal of Cancer Prevention, 2014
Carbohydrate polymers, Sep 20, 2016
The oxidative stability of (-)-epigallocatechin-3-gallate (EGCG) incorporated as inclusion comple... more The oxidative stability of (-)-epigallocatechin-3-gallate (EGCG) incorporated as inclusion complexes (ICs) in sulfobutylether-β-cyclodextrin sodium (SBE-β-CD) and then ionotropically crosslinked with chitosan hydrochloride (CSH) into nanoparticles were investigated. EGCG-loaded CSH-SBE-β-CD nanoparticles (CSNs) were physically unstable at higher pH and temperature. The particle size of CSNs was unchanged in the pH range of 3-5, but the microenvironment of EGCG-IC appeared to be intact until the pH increased to 6.5 by fluorescence spectroscopy. The physical structure of EGCG-ICs was also affected during storage in addition to CSNs, which was further affected as temperature increased from 25 to 55°C. The decrease in antioxidant activities of EGCG-ICs and free EGCG with increasing pH, storage time and temperature were modest compared to the prominent decreases in antioxidant activities of EGCG-loaded CSNs. The extreme entrapment of EGCG-ICs and/or free EGCG in the aggregated CSNs restr...
Food Hydrocolloids, 2015
Abstract Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosa... more Abstract Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanoparticles at various concentrations. The composites films were compared in terms of antimicrobial activity, thermomechanical, physicochemical and barrier properties. The thermal stability of the films was studied using thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements were used to study the interactions and compatibility between the polysaccharides with in the films. The microstructure of the films was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Incorporation of chitosan nanoparticles improved mechanical, physicochemical and barrier properties. Tensile strength was increased by 35.73 MPa while the elongation was decreased by 7.21%. Water solubility and water vapor permeability (WVP) were reduced by 74.3% and 22.7%, respectively. The compact structure of the chitosan nanoparticles reduced the free volume of the polymer matrix more than bulk chitosan by obstructing the diffusion of water and thereby decreasing the moisture content of the films. Additionally, the microstructure of the films showed that the nanoparticles were distributed homogenously with in the structure and increased the roughness of the surface. However, tara gum films with bulk chitosan exhibited better antimicrobial activity. Incorporation of chitosan nanoparticles produced films less effective against Escherichia coli compared to Staphylococcus aureus, and their antimicrobial activity was reduced at high concentrations probably due to agglomeration.
Food Hydrocolloids, 2015
ABSTRACT Consumption of essential oils (EOs) and their components, such as eugenol (EU) may reduc... more ABSTRACT Consumption of essential oils (EOs) and their components, such as eugenol (EU) may reduce chronic disorders, but their use in food is currently limited because of poor solubility and low bioavailability. The aim of this work was to study the influence of carrier oil type, particle size on in vitro lipid digestion and EU release using canola (LCT) and MCT oil-in- 3 water emulsions with different droplet diameters (Coarse > 3000 nm , NE1 > 300 nm and 3 NE2 > 150 nm). There was a progressive increase in the mean particle size of coarse emulsions of both LCT & MCT oils as they passed through simulated gastrointestinal tract consisting of mouth, stomach and intestine phases, which was due to droplet coalescence, flocculation and digestion. However, NE1 and NE2 nanoemulsions showed appreciable increase in particle size after exposure to the simulated intestinal fluid. The rate and extent of in vitro lipid digestion increased with decreasing mean droplet diameter (NE2 ≈ NE1 » 4 Coarse) in both MCT & LCT emulsions. However, MCT emulsions showed faster rate of in vitro lipid digestion which was attributed to more exposure of droplets with the lipase. There 4 was also an appreciable increase in release percentage of eugenol with decreasing droplet diameter (NE2 > NE1 > Coarse) and it was higher in LCT (84%) emulsions which was attributed to large hydrophobic cores that better solubilize EU.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
Abstract Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last de... more Abstract Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade because of their numerous applications. In this study, we describe conditions to optimize chitosan nanoparticles as potential nano-fillers in edible films. The ionic cross-linking between the cationic amino groups on the chitosan (CS) chain and the anionic phosphate groups of sodium tripolyphosphate (TPP) was verified via FTIR. Particle size, polydispersity index (PDI) and surface ζ-potential were controlled by chitosan's Mw and concentration, CS:TPP mass ratio, and external conditions such as pH and salinity of the initial chitosan solution. Post-processing methods such as centrifugation and ultra-sonication were used to further control particle size. We show that particle size can be controlled by selecting appropriate conditions. Particles with sizes below 120 nm were produced at different CS:TPP mass ratios depending on the CS concentration. Dilute NaCl was the optimal solution ionic composition that decreased the size by 25% and also resulted in a narrow particle size distribution. We show using UV–vis spectrophotometry that particles of different size, separated by centrifugation had different phosphorus content. Ultra-sonication can be used to reduce the size by 50% but long time caused fragmentation of the nanoparticles. Transmission electron microscopy (TEM) revealed the differences in the morphology of chitosan nanoparticles under various fabrication conditions.
In this study eugenol (EU) loaded nanoemulsions (NEs) emulsified with modified starch were prepar... more In this study eugenol (EU) loaded nanoemulsions (NEs) emulsified with modified starch were prepared and their apoptotic potential against liver and colon cancer cells was examined in comparison with bulk EU. Materials and Methods: We prepared stable EU loaded NEs whcih were characterized by dynamic light scattering, centrifugation and gas chromatography. Furthermore, cell viability was determined using MTT
assay, and apoptosis and cell cycle analysess by flow cytometry. Results: HB8065 (liver) and HTB37 (colon) cells when treated with EU:CA NEs demonstrated greater apoptotic cells percentages as evidenced by microscopic images and flow cytometric evaluations. It was observed that EU and EU:CA NE induced apoptosis in both cell lines via reactive oxygen species (ROS) generation. Conclusions: The present study demonstrated that ROS plays a critical role in EU and EU:CA NE induced apoptosis.
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum
effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions.
Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade beca... more Chitosan–tripolyphosphate nanoparticles have been extensively studied during the last decade because of their numerous applications. In this study, we describe conditions to optimize chitosan nanoparticles
as potential nano-fillers in edible films. The ionic cross-linking between the cationic amino groups on the chitosan (CS) chain and the anionic phosphate groups of sodium tripolyphosphate (TPP) was verified via
FTIR. Particle size, polydispersity index (PDI) and surface -potential were controlled by chitosan’s Mw and concentration, CS:TPP mass ratio, and external conditions such as pH and salinity of the initial chitosan solution. Post-processing methods such as centrifugation and ultra-sonication were used to further control particle size. We show that particle size can be controlled by selecting appropriate conditions.
Particles with sizes below 120 nm were produced at different CS:TPP mass ratios depending on the CS concentration. Dilute NaCl was the optimal solution ionic composition that decreased the size by 25% and
also resulted in a narrow particle size distribution. We show using UV–vis spectrophotometry that particles of different size, separated by centrifugation had different phosphorus content. Ultra-sonication can
be used to reduce the size by 50% but long time caused fragmentation of the nanoparticles. Transmission electron microscopy (TEM) revealed the differences in the morphology of chitosan nanoparticles under
various fabrication conditions.
Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanopar... more Tara gum films were successfully produced with the inclusion of bulk chitosan or chitosan nanoparticles at various concentrations. The composites films were compared in terms of antimicrobial activity, thermomechanical, physicochemical and barrier properties. The thermal stability of the films was studied using thermogravimetric analysis (TGA). Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements were used to study the interactions and compatibility between the polysaccharides with in the films. The microstructure of the films was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Incorporation of chitosan nanoparticles improved mechanical, physicochemical and barrier properties. Tensile strength was increased by 35.73 MPa while the elongation was decreased by 7.21%. Water solubility and water vapor permeability (WVP) were reduced by 74.3% and 22.7%, respectively. The compact structure of the chitosan nano-particles reduced the free volume of the polymer matrix more than bulk chitosan by obstructing the diffusion of water and thereby decreasing the moisture content of the films. Additionally, the micro-structure of the films showed that the nanoparticles were distributed homogenously with in the structure and increased the roughness of the surface. However, tara gum films with bulk chitosan exhibited better antimicrobial activity. Incorporation of chitosan nanoparticles produced films less effective against Escherichia coli compared to Staphylococcus aureus, and their antimicrobial activity was reduced at high concentrations probably due to agglomeration.
Journal of agricultural and food chemistry, Jan 31, 2015
Gelatin films incorporated with chitosan nanoparticles of various free/encapsulated tea polypheno... more Gelatin films incorporated with chitosan nanoparticles of various free/encapsulated tea polyphenols (TP) ratios were prepared in order to investigate the influence of different ratios on physico-chemical and antioxidant properties of films. The TP containing nanoparticles were prepared by cross-linking chitosan hydrochloride (CSH) with sulfobutylether-β-cyclodextrin sodium (SBE-β-CD) at three different encapsulation efficiencies (EE, ~50%, ~80% and ~100%) of TP. The stability of TP-loaded nanoparticles was maintained during film drying process from the analysis of free TP content in the redissolved film solutions. Composite films showed no significant difference in visual aspects while the light transmittance (250-550 nm) was decreased with incorporation of TP. Nanoparticles appeared to be homogeneously dispersed within the film matrix by microstructure analysis (SEM and AFM). TP loaded films had ferric reducing and DPPH radical scavenging power that corresponded to the EEs. Sunflow...
Archives of microbiology, 2015
Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cel... more Flow cytometry exactly discriminated three subpopulations, i.e., viable, damage and sublethal cells of L. monocytogenes, S. aureus and E. coli when treated at their MIC values. Purity gum ultra (PGU) a large molecule surfactant-based CO nanoemulsion exerted significant impact on cellular subpopulations of L. monocytogenes and S. aureus, with more membrane-damaged cells. On the other hand, when compared with bulk CO the results showed minimum membrane damage and more viable cells, whereas PGU CO nanoemulsion showed minimum effect on cellular subpopulation and represented more viable than damaged cells in case of E. coli. Similarly, Tween 80 a small molecule surfactant-based CO nanoemulsion showed limited overall activity against three tested microorganisms with more viable cells. We conclude that it was due to sequestration of CO constituents in interfaces, less availability in aqueous phase and finally inhibit bactericidal activity. Moreover, both CO and CO nanoemulsions showed memb...
Carbohydrate Polymers, 2014
The aim of this study was to evaluate tara gum as edible film material as well as the influence o... more The aim of this study was to evaluate tara gum as edible film material as well as the influence of polyols as plasticizers on the properties of the films. Thermomechanical, physicochemical and barrier properties were determined as a function of plasticizer type and concentration. Glycerol, sorbitol and PEG 400 were used in the range of 0.075-0.3g/tarag. Glycerol was the best plasticizer in terms of mechanical properties with the highest elongation (16-44%) and resistance (45-90 MPa). Sorbitol presented the best barrier properties with the lowest hydrophilicity and water vapour permeability (0.24-0.34 g mm m(-2)h(-1) kPa(-1)). Fourier transform infrared (FTIR) spectroscopy showed no significant effect on the structure of the polysaccharide. Dynamic mechanical analysis (DMA) revealed that incorporation of plasticizers increased the mobility of the polymer chains and reduced the glass transition and melting temperature by 30 and 100 °C respectively.
Food Chemistry, 2014
The objective of this study was to analyze the influence of thermal-acid treatment on the formati... more The objective of this study was to analyze the influence of thermal-acid treatment on the formation of resistant starch (RS). The maximum RS content in citric acid-heat treated starches (CAHT) reached 36.55%, which was 7 times higher of that in native starch. According to HPSEC-MALLS-RI analysis, amylopectin was more susceptible to hydrolysis than amylose during citric acid-heat treatment (CAH). X-ray measurement revealed that even though the starch crystalline pattern was changed from A-type to a more resistant B-type after CAH, the fraction of crystalline region decreased from 21.16% to 8.37%. The hydroxyls on the starch chains were substituted by the citric acid anhydrides during CAH according to FT-IR analysis, which led to the formation of ester bond cross-linking structures in starch granules, and it could be the main contribution to the increase of RS content in CAHT samples.