Search

The ultrasonic (US)-treated batter mixtures of commercial methylcellulose (MC) as the fried potato strips' coating layer were demonstrated. The layer formed a rapid gel that absorbs the substrate's water content and related functional groups that contribute to acrylamide formation reduction. Different concentrations of MC (0.5-2.0 w/v %) mixtures were subjected to US at 20 W to evaluate coating layers' effect prior to the deep-frying process. At 1% w/v concentration batter mixture, the USMC layer reduced the highest acrylamide value. For comparison purposes, the differences in the acrylamide content of the USMC, the non-USMC and the uncoated samples were 64.7 ± 5.04, 156.4 ± 7.44 and 344.1 ± 5.39 ng g-1, respectively. The results were supported with lower oil uptake and water retention of the USMC compared with the non-USMC with the values of 2.2 g/100g and 28.6 g/100g with 5.1 g/100g and 47 g/100g, respectively.

The ultrasonic (US)-treated batter mixtures of commercial methylcellulose (MC) as the fried potato strips' coating layer were demonstrated. The layer formed a rapid gel that absorbs the substrate's water content and related functional groups that contribute to acrylamide formation reduction. Different concentrations of MC (0.5-2.0 w/v %) mixtures were subjected to US at 20 W to evaluate coating layers' effect prior to the deep-frying process. At 1% w/v concentration batter mixture, the USMC layer reduced the highest acrylamide value. For comparison purposes, the differences in the acrylamide content of the USMC, the non-USMC and the uncoated samples were 64.7 ± 5.04, 156.4 ± 7.44 and 344.1 ± 5.39 ng g-1, respectively. The results were supported with lower oil uptake and water retention of the USMC compared with the non-USMC with the values of 2.2 g/100g and 28.6 g/100g with 5.1 g/100g and 47 g/100g, respectively.

The potential of producing L-isoleucine crystals with the aid of electric potential and its effect on the nucleation kinetics of L-isoleucine were probed using polythermal and isothermal crystallisation techniques, assisted with 5 V, 9 V, and 20 V electric potentials. The polythermal experiments were conducted with cooling rates of 0.1 °C/min–0.7 °C/min, whilst isothermal crystallisation was conducted with a supersaturation of 1.30–1.70, and both were carried out in a 200 mL temperature-controlled jacketed reactor. Prediction of the nucleation rate and its associated parameters for isothermal crystallisation was carried out using a molecular dynamics simulation. In both crystallisation techniques, electric potentials increased the nucleation rate, but the intensity of the electric potential had less impact on the measured parameters. Nucleation rates for 5 V isothermal crystallisation were in the order of 1010 higher than for polythermal crystallisation. Electric potential doubled the nucleation rates for polythermal crystallisation and increased the nucleation rates 12-fold in isothermal crystallisation. The isothermal technique produced the form B polymorph, but mixtures of forms A and B were produced in polythermal crystallisation. The predicted critical number of molecules, N*, and the critical radius, r*, were in good agreement with the experimental data, with a higher predicted nucleation rate in the order of 102

Polyetherimide (PEI) is recognized as a potential candidate for electrochemical sensor matrix which can be used for heavy metal ion and reactive chemical substance sensing applications. However, the relatively low conductivity of PEI material limits its usage of electrochemical sensor applications. Modifying PEI membrane considerably improve the electron conductivity and electrochemical property of polymer. Conductive polyetherimide-graphene oxide (PEI-GO) composite nanofiber membrane was synthesized via electrospinning technique in order to modify electrochemical sensor electrodes. In order to optimize the electrospinning process protocol such as viscosity, surface tension and conductivity and obtained smooth electrospun fiber, PEI were electrospun from two different solvents namely n-methyl-2-pyrrolidone (NMP) and combination of NMP/ dimethylformamide (DMF). Physical and electrical properties of the nanofiber were analysed in terms of its hydrophobicity, porosity and conductivity by manipulating the concentration of PEI from 20 wt% to 30 wt% and GO loading from 0.1 wt% to 0.5 wt%. Electrospun of 25 wt% PEI in NMP/DMF produced the highest porosity and liquid uptake of 97.81% and 2846.23% respectively. The addition of GO at 0.5 wt% into 25 wt% of PEI (NMP/DMF) improved the porosity and liquid uptake up to 98.83% and 5400%,respectively, while the conductivity increases to 32.71 µS/cm which is 10 folds higher than GO free PEI fiber. When the conductivity of drop-casted PEI-GO modified electrodes was compared to the electrospun PEI-GO fiber modified electrodes, the latter showed 2-3 folds higher. Proposed PEI-GO electrospun fiber with the enhanced conductivity, porosity and hydrophobicity along with high chemical stability can be used as an efficient conductive matrix for electrochemical electrode applications such as heavy metal ion sensing and reactive chemical sensing application.

Polyetherimide (PEI) is recognized as a potential candidate for electrochemical sensor matrix which can be used for heavy metal ion and reactive chemical substance sensing applications. However, the relatively low conductivity of PEI material limits its usage of electrochemical sensor applications. Modifying PEI membrane considerably improve the electron conductivity and electrochemical property of polymer. Conductive polyetherimide-graphene oxide (PEI-GO) composite nanofiber membrane was synthesized via electrospinning technique in order to modify electrochemical sensor electrodes. In order to optimize the electrospinning process protocol such as viscosity, surface tension and conductivity and obtained smooth electrospun fiber, PEI were electrospun from two different solvents namely n-methyl-2-pyrrolidone (NMP) and combination of NMP/ dimethylformamide (DMF). Physical and electrical properties of the nanofiber were analysed in terms of its hydrophobicity, porosity and conductivity by manipulating the concentration of PEI from 20 wt% to 30 wt% and GO loading from 0.1 wt% to 0.5 wt%. Electrospun of 25 wt% PEI in NMP/DMF produced the highest porosity and liquid uptake of 97.81% and 2846.23% respectively. The addition of GO at 0.5 wt% into 25 wt% of PEI (NMP/DMF) improved the porosity and liquid uptake up to 98.83% and 5400%,respectively, while the conductivity increases to 32.71 µS/cm which is 10 folds higher than GO free PEI fiber. When the conductivity of drop-casted PEI-GO modified electrodes was compared to the electrospun PEI-GO fiber modified electrodes, the latter showed 2-3 folds higher. Proposed PEI-GO electrospun fiber with the enhanced conductivity, porosity and hydrophobicity along with high chemical stability can be used as an efficient conductive matrix for electrochemical electrode applications such as heavy metal ion sensing and reactive chemical sensing application.

In this study, the controlled nucleation and growth of gold nanoparticles (GNPs) were investigated using a self-repelled mist in a liquid chemical reaction environment. An electrospray-based chemical reduction method was conducted in the aqueous region and at room temperature to synthesize the polymeric-stabilized gold nanoparticles. The electrospray technique was used to atomize a hydrogen tetrachloraurate (III) (HAuCl4) precursor solution into electrostatically charged droplets. The atomized droplets were dispersed in an aqueous reaction bath containing L-ascorbic acid as a reducing agent and polyvinylpyrrolidone (PVP) as a stabilizer. The effect of the electrospray parameters, specifically the flow rate and electrospray droplet size, as well as the reaction conditions such as the concentration of reactants, pH, and stabilizer (PVP), were investigated. The mean diameter of the GNPs increased from around 4 to 9 nm with an increase in the electrospray flow rate, droplet size, and current passing through the electrospray jet. Spherical and monodispersed GNPs were synthesized at a relatively high flow rate of 2 mL/h and a moderate concentration of 2 mM of precursor solution. The smallest-sized GNP with a high monodispersity was obtained in the reaction bath at a high pH of 10.5 and in the presence of PVP. It is expected that continuous and mass production of the engineered GNPs and other noble metal nanoparticles could be established for scaling up nanoparticle production via the proposed electrospray-based chemical reduction method.

The potential of producing L-isoleucine crystals with the aid of electric potential and its effect on the nucleation kinetics of L-isoleucine were probed using polythermal and isothermal crystallisation techniques, assisted with 5 V, 9 V, and 20 V electric potentials. The polythermal experiments were conducted with cooling rates of 0.1 °C/min–0.7 °C/min, whilst isothermal crystallisation was conducted with a supersaturation of 1.30–1.70, and both were carried out in a 200 mL temperature-controlled jacketed reactor. Prediction of the nucleation rate and its associated parameters for isothermal crystallisation was carried out using a molecular dynamics simulation. In both crystallisation techniques, electric potentials increased the nucleation rate, but the intensity of the electric potential had less impact on the measured parameters. Nucleation rates for 5 V isothermal crystallisation were in the order of 1010 higher than for polythermal crystallisation. Electric potential doubled the nucleation rates for polythermal crystallisation and increased the nucleation rates 12-fold in isothermal crystallisation. The isothermal technique produced the form B polymorph, but mixtures of forms A and B were produced in polythermal crystallisation. The predicted critical number of molecules, N*, and the critical radius, r*, were in good agreement with the experimental data, with a higher predicted nucleation rate in the order of 102

Ultrasonic treatment (UT) effects on methylcellulose (MC) for the food coating purpose prior to deep-fat frying process of potato strips were demonstrated. Different concentration of MC (0.5–2.0 wt/vol%) solutions were subjected to UT at 20 W to evaluate the effect of UT treated coatings on rheological behavior of the coated samples and their efficiency in minimizing the oil uptake. Application of UT to methylcellulose (UTMC) clearly showed a phase transition from fluid- to gel-like between 20 and 65°C with the increasing in the oscillatory frequency and temperature ramp test of UTMC showed the sol–gel transition occurrence is lower than non-UTMC at 20 and 29°C, respectively, within the linear viscoelastic region. When the MC concentrations were varied, the most effective concentration was noticed to occur at 1.0 (wt/vol%) UTMC whereby the relative variation of water retention and oil uptake were reduced to about 49.9 and 31.0%, respectively, as compared to 1.0 wt/vol% non-UTMC formulation. Experimental results affirm that UTMC coating application can be used successively to improve rheological properties of MC by minimizing oil uptake on fried food.

The potential of Nelumbo nucifera in treating contaminated surface water was investigated in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, and nitrate reduction. Batch type lab-scale container cultivated with N. nucifera was exposed to the contaminated surface water for 30 days. Nitrate (NO3−) adsorption and pH level were monitored continuously to identify the plant survival and to avoid any additional contaminants into the samples such as plant decay. For comparison, water lily, Nymphaea, was prepared using the same experimental setup. After 30 days of phytoremediation, the BOD and COD values of the treated water using N. nucifera was significantly reduced to 97.1% and 55%, respectively, due to the unique gas transport mechanism that thermodynamically drive O2 gas from leaves at the water surface to the buried rhizomes located in the anoxic sediments. When treated with Nymphaea, the BOD value in water decreased by 64.5% and the COD value increased by 50.5%. The results indicate that N. nucifera was able to remove the organic contaminants from the surface water by supplying adequate amount of 0.2–2.1 mL/min O2 gas to increase the microbial activities from the control condition.

The potential of Nelumbo nucifera in treating contaminated surface water was investigated in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, and nitrate reduction. Batch type lab-scale container cultivated with N. nucifera was exposed to the contaminated surface water for 30 days. Nitrate (NO3−) adsorption and pH level were monitored continuously to identify the plant survival and to avoid any additional contaminants into the samples such as plant decay. For comparison, water lily, Nymphaea, was prepared using the same experimental setup. After 30 days of phytoremediation, the BOD and COD values of the treated water using N. nucifera was significantly reduced to 97.1% and 55%, respectively, due to the unique gas transport mechanism that thermodynamically drive O2 gas from leaves at the water surface to the buried rhizomes located in the anoxic sediments. When treated with Nymphaea, the BOD value in water decreased by 64.5% and the COD value increased by 50.5%. The results indicate that N. nucifera was able to remove the organic contaminants from the surface water by supplying adequate amount of 0.2–2.1 mL/min O2 gas to increase the microbial activities from the control condition.

Owing to the annually increasing market value of pure agarwood oil, the extractedagarwood oil from Aquilaria malaccensis was emulsified in an aqueous solution using non-ionic surfactant (Tween 80). The surfactant concentration of 0.0167% was determined as the criticalmicelle concentration (CMC) with an interfacial tension value of 0.014 mNm-1. The adsorption of surfactant at the oil/water interface at the CMC value, however, reduced the zeta potential of the emulsified oil from –45 to –43 mV, and increased its size from 85 to 89 nm. Outside of the CMC value, the emulsified oil droplets tended to coalesce, owing to insufficient coverage of the surfactant at oil/water interface and Ostwald ripening. The droplet size distribution and zeta potential value of the emulsified oil droplets produced at the CMC were the most stable over a month of storage. No significant changes in the emulsified droplet size occurred when the pH conditions varied from pH 3 to 10. The emulsified droplets images obtained from transmission electron microscopy analysis showed a reduction in the layer thickness of the surfactant from 30 to 10 nm in acidic condition and 30 to 19 nm in alkaline condition. The agarwood oil emulsification at CMC value enhance the stability of chemically unstable compounds from degradation.

A novel application of sodium dodecyl sulphate-polyacrylamide gel electrophoresis was evaluated to differentiate the quality of two commercial cinnamon bark oil samples extracted by steam distillation and cold pressed. Prior to the electrophoresis, cinnamon oils were emulsified with non-ionic surfactant, tween 80 at 2% v/v of critical aggregation concentration. The droplets prepared were within 30 to 70 nm size and zeta potential values of -4 to -12 mV consisted of certain amount of bioactive compounds that responded to specific molecular mass and electrophoretic mobility so that separation using SDSPAGE can be performed. The resolution bands at 21% gel with 48% acrylamide concentration and 3.33% of cross-linker demonstrated that high quality (steam distilled) cinnamon oil migrated slower through gel due to its large molecular weight components when compared to the low quality (cold pressed) cinnamon oil. The difference in the relative mobility, 0.68 and 0.75 of emulsified steam distilled and cold pressed cinnamon bark oils, respectively, was attributed by their entrapped components impinging upon their electrophoretic mobility.

A novel application of sodium dodecyl sulphate-polyacrylamide gel electrophoresis was evaluated to differentiate the quality of two commercial cinnamon bark oil samples extracted by steam distillation and cold pressed. Prior to the electrophoresis, cinnamon oils were emulsified with non-ionic surfactant, tween 80 at 2% v/v of critical aggregation concentration. The droplets prepared were within 30 to 70 nm size and zeta potential values of -4 to -12 mV consisted of certain amount of bioactive compounds that responded to specific molecular mass and electrophoretic mobility so that separation using SDSPAGE can be performed. The resolution bands at 21% gel with 48% acrylamide concentration and 3.33% of cross-linker demonstrated that high quality (steam distilled) cinnamon oil migrated slower through gel due to its large molecular weight components when compared to the low quality (cold pressed) cinnamon oil. The difference in the relative mobility, 0.68 and 0.75 of emulsified steam distilled and cold pressed cinnamon bark oils, respectively, was attributed by their entrapped components impinging upon their electrophoretic mobility.

Owing to the annually increasing market value of pure agarwood oil, the extractedagarwood oil from Aquilaria malaccensis was emulsified in an aqueous solution using non-ionic surfactant (Tween 80). The surfactant concentration of 0.0167% was determined as the criticalmicelle concentration (CMC) with an interfacial tension value of 0.014 mNm-1. The adsorption of surfactant at the oil/water interface at the CMC value, however, reduced the zeta potential of the emulsified oil from –45 to –43 mV, and increased its size from 85 to 89 nm. Outside of the CMC value, the emulsified oil droplets tended to coalesce, owing to insufficient coverage of the surfactant at oil/water interface and Ostwald ripening. The droplet size distribution and zeta potential value of the emulsified oil droplets produced at the CMC were the most stable over a month of storage. No significant changes in the emulsified droplet size occurred when the pH conditions varied from pH 3 to 10. The emulsified droplets images obtained from transmission electron microscopy analysis showed a reduction in the layer thickness of the surfactant from 30 to 10 nm in acidic condition and 30 to 19 nm in alkaline condition. The agarwood oil emulsification at CMC value enhance the stability of chemically unstable compounds from degradation.

An industrial enzyme, Cyclodextrin glucanotransferase (CGTase), was immobilised in polyvinyl alcohol (PVA) nanofiber (average diameter around 200 nm) membrane via co-electrospinning of the CGTase/PVA mixture followed with glutaraldehyde vapour phase cross-linking. Addition of enzyme with concentration ranging from 1.5 to 7.5 % to the PVA solution (8 wt%) caused significant changes to the liquid jet behaviours which consequently affected the nanofiber structures and sizes. Incorporation of CGTase in the PVA membrane was confirmed by Raman spectroscopic analysis. The Raman spectra also showed no structural changes occured to the enzyme after subjected to the electrostatic spinning and cross-linking reaction. The immobilised enzyme showed excellent catalytic efficiency with up to 3.6 times higher enzyme loading, 25 % higher activity and good reusability in comparison with CGTase/PVA film made up from the same starting solution (control).

An industrial enzyme, Cyclodextrin glucanotransferase (CGTase), was immobilised in polyvinyl alcohol (PVA) nanofiber (average diameter around 200 nm) membrane via co-electrospinning of the CGTase/PVA mixture followed with glutaraldehyde vapour phase cross-linking. Addition of enzyme with concentration ranging from 1.5 to 7.5 % to the PVA solution (8 wt%) caused significant changes to the liquid jet behaviours which consequently affected the nanofiber structures and sizes. Incorporation of CGTase in the PVA membrane was confirmed by Raman spectroscopic analysis. The Raman spectra also showed no structural changes occured to the enzyme after subjected to the electrostatic spinning and cross-linking reaction. The immobilised enzyme showed excellent catalytic efficiency with up to 3.6 times higher enzyme loading, 25 % higher activity and good reusability in comparison with CGTase/PVA film made up from the same starting solution (control).

A study on the feasibility of using gel electrophoresis technique in grading the agarwood oil quality was investigated. Prior to electrophoresis, the emulsified agarwood oil droplets were screened by a diffuse layer of ions that have equal absolute charge to that of the droplets surface charge in aqueous phase. The condition was obtained by varying the concentrations of non-ionic surfactant; Tween 80 until the critical aggregation concentration (CAC) value of 0.0167% (v/v) was achieved. The prepared droplets suspended in the aqueous within nano-metre size and had ability to migrate through the agarose gel with its own specific electrophoretic mobility. However, due to the limitation of gel pore size, only large oil droplets (>200 nm) indicated visible bands. Overall, a novel work for grading the emulsified agarwood oil droplet with its own electrical properties was feasible.

In this work, a non-thermal solidified method of Jasmine extract was developed via the electrostatic atomizer or electrospray technique. The electrospray technique is dependent on two continuous processes which are water evaporation and droplet fission. To verify the water evaporation rates of the atomized droplets, the deposition trajectory distance were varied from 10 to 30 cm. The morphology and size distribution of the deposits were observed and analyzed. From the experimental results, it was noticed that the evaporation rates of the atomized droplets reduced from 2.65 x 10-10 - 1.1 x 10-10 g/s as the trajectory distances of the atomized droplet increased from 10-30 cm. Meanwhile, the droplet fission is increased from 12.5 to 16 disintegrations as the distance went further. The morphology and particles size of the solidified compound were analyzed by SEM and ImageJ software respectively.

Immobilisation of cyclodextrin glucanotransferase (CGTase) on nanofibres was demonstrated. CGTase solution (1% v/v) and PVA (8 wt%) solution were mixed followed by electrospinning (−9 kV, 3 h). CGTase/PVA nanofibres with an average diameter of 176 ± 46 nm were successfully produced. The nanofibres that consist of immobilised CGTase were crosslinked with glutaraldehyde vapour. A CGTase/PVA film made up from the same mixture and treated the same way was used as a control experiment. The immobilised CGTase on nanofibres showed superior performance with nearly a 2.5 fold higher enzyme loading and 31% higher enzyme activity in comparison with the film.

A study on the feasibility of using gel electrophoresis technique in grading the agarwood oil quality was investigated. Prior to electrophoresis, the emulsified agarwood oil droplets were screened by a diffuse layer of ions that have equal absolute charge to that of the droplets surface charge in aqueous phase. The condition was obtained by varying the concentrations of non-ionic surfactant; Tween 80 until the critical aggregation concentration (CAC) value of 0.0167% (v/v) was achieved. The prepared droplets suspended in the aqueous within nano-metre size and had ability to migrate through the agarose gel with its own specific electrophoretic mobility. However, due to the limitation of gel pore size, only large oil droplets (>200 nm) indicated visible bands. Overall, a novel work for grading the emulsified agarwood oil droplet with its own electrical properties was feasible.

Immobilisation of cyclodextrin glucanotransferase (CGTase) on nanofibres was demonstrated. CGTase solution (1% v/v) and PVA (8 wt%) solution were mixed followed by electrospinning (−9 kV, 3 h). CGTase/PVA nanofibres with an average diameter of 176 ± 46 nm were successfully produced. The nanofibres that consist of immobilised CGTase were crosslinked with glutaraldehyde vapour. A CGTase/PVA film made up from the same mixture and treated the same way was used as a control experiment. The immobilised CGTase on nanofibres showed superior performance with nearly a 2.5 fold higher enzyme loading and 31% higher enzyme activity in comparison with the film.

In this work, a non-thermal solidified method of Jasmine extract was developed via the electrostatic atomizer or electrospray technique. The electrospray technique is dependent on two continuous processes which are water evaporation and droplet fission. To verify the water evaporation rates of the atomized droplets, the deposition trajectory distance were varied from 10 to 30 cm. The morphology and size distribution of the deposits were observed and analyzed. From the experimental results, it was noticed that the evaporation rates of the atomized droplets reduced from 2.65 x 10-10 - 1.1 x 10-10 g/s as the trajectory distances of the atomized droplet increased from 10-30 cm. Meanwhile, the droplet fission is increased from 12.5 to 16 disintegrations as the distance went further. The morphology and particles size of the solidified compound were analyzed by SEM and ImageJ software respectively.

Electrophoretic deposition (EPD) technique has been demonstrated to remove arsenic with natural adsorbent (fine iron oxide particles) in tap water samples. Characterizations of metal element particularly arsenic and fine iron oxide particles in tap water from two different locations, i.e. commercial and residential areas, were conducted. Results showed that the concentration of arsenic in tap water from residential area was higher than commercial area samples i.e. 0.022 ± 0.004 and 0.016 ± 0.008 ppm, respectively. The same finding was observed in zeta potential value where it was higher in the residential area than commercial area, i.e. −42.27 ± 0.12 and −34.83 ± 0.23 mV, respectively. During the removal of arsenic using the EPD technique, direct current (DC) voltage was varied from 5 to 25V at a constant electrode distance of 30 mm. Effect of zeta potential, voltage and electrode type were intensively investigated. High percentage removal of arsenic was obtained from carbon plate than carbon fibre electrode. The percentage removal of arsenic from all samples slightly decreased with increasing of the applied voltage. EDX analysis confirmed that arsenic has adsorbed onto deposited iron oxide particles on the anode electrode. Overall, EPD technique was found to be successful in removing arsenic onto fine iron oxide particles in tap water with 26% ± 1.05 of removal.

Electrophoretic deposition (EPD) technique has been demonstrated to remove arsenic with natural adsorbent (fine iron oxide particles) in tap water samples. Characterizations of metal element particularly arsenic and fine iron oxide particles in tap water from two different locations, i.e. commercial and residential areas, were conducted. Results showed that the concentration of arsenic in tap water from residential area was higher than commercial area samples i.e. 0.022 ± 0.004 and 0.016 ± 0.008 ppm, respectively. The same finding was observed in zeta potential value where it was higher in the residential area than commercial area, i.e. −42.27 ± 0.12 and −34.83 ± 0.23 mV, respectively. During the removal of arsenic using the EPD technique, direct current (DC) voltage was varied from 5 to 25V at a constant electrode distance of 30 mm. Effect of zeta potential, voltage and electrode type were intensively investigated. High percentage removal of arsenic was obtained from carbon plate than carbon fibre electrode. The percentage removal of arsenic from all samples slightly decreased with increasing of the applied voltage. EDX analysis confirmed that arsenic has adsorbed onto deposited iron oxide particles on the anode electrode. Overall, EPD technique was found to be successful in removing arsenic onto fine iron oxide particles in tap water with 26% ± 1.05 of removal.

In this study, the potential of electrohydrodynamic atomization or electrospraying to produce nanometer-order CGTase particles from aqueous suspension was demonstrated. CGTase enzyme was prepared in acetate buffer solution (1% v/v), followed by electrospraying in stable Taylor cone-jet mode. The deposits were collected on aluminium foil (collector) at variable distances from the tip of spraying needle, ranging from 10 to 25 cm. The Coulomb fission that occurs during electrospraying process successfully transformed the enzyme to the solid state without any functional group deterioration. The functional group verification was conducted by FTIR analysis. Comparison between the deposit and the as-received enzyme in dry state indicates almost identical spectra. By increasing the distance of the collector from the needle tip, the average particle size of the solidified enzyme was reduced from 200 ± 117 nm to 75 ± 34 nm. The average particle sizes produced from the droplet fission were in agreement with the scaling law models. Enzyme activity analysis showed that the enzyme retained its initial activity after the electrospraying process. The enzyme particles collected at the longest distance (25 cm) demonstrated the highest enzyme activity, which indicates that the activity was controlled by the enzyme particle size.

In this study, the potential of electrohydrodynamic atomization or electrospraying to produce nanometer-order CGTase particles from aqueous suspension was demonstrated. CGTase enzyme was prepared in acetate buffer solution (1% v/v), followed by electrospraying in stable Taylor cone-jet mode. The deposits were collected on aluminium foil (collector) at variable distances from the tip of spraying needle, ranging from 10 to 25 cm. The Coulomb fission that occurs during electrospraying process successfully transformed the enzyme to the solid state without any functional group deterioration. The functional group verification was conducted by FTIR analysis. Comparison between the deposit and the as-received enzyme in dry state indicates almost identical spectra. By increasing the distance of the collector from the needle tip, the average particle size of the solidified enzyme was reduced from 200 ± 117 nm to 75 ± 34 nm. The average particle sizes produced from the droplet fission were in agreement with the scaling law models. Enzyme activity analysis showed that the enzyme retained its initial activity after the electrospraying process. The enzyme particles collected at the longest distance (25 cm) demonstrated the highest enzyme activity, which indicates that the activity was controlled by the enzyme particle size.

Deposition of titanium dioxide (TiO2) nanoparticles was conducted by using eletrospray method. 0.05wt% of titanium dioxide suspension was prepared and characterized by using Malvern Zetasizer prior to the experiment. From Zetasizer results, stable suspension condition was obtained which is at pH 2 with zeta potential value of ±29.0 mV. In this electrospraying, the suspension was pumped at flowrate of 5 ml/hr by using syringe pump. The input voltage of 2.1 kV was applied at the nozzle tip and counter electrode. Electrosprayed particles were collected on the grounded aluminium plate substrate which was placed at 10–20 cm from counter electrode. Particles were then characterized using FESEM and average size of electrosprayed particles obtained. Initial droplet size was calculated by scaling law and compared with FE-SEM results in order to prove droplet fission occur during electrospray. Due to the results obtained, as the working distance increase from 10–20 cm the deposited TiO2 droplet size decrease from 247–116 nm to show droplet fission occur during the experiment.

Deposition of titanium dioxide (TiO2) nanoparticles was conducted by using eletrospray method. 0.05wt% of titanium dioxide suspension was prepared and characterized by using Malvern Zetasizer prior to the experiment. From Zetasizer results, stable suspension condition was obtained which is at pH 2 with zeta potential value of ±29.0 mV. In this electrospraying, the suspension was pumped at flowrate of 5 ml/hr by using syringe pump. The input voltage of 2.1 kV was applied at the nozzle tip and counter electrode. Electrosprayed particles were collected on the grounded aluminium plate substrate which was placed at 10–20 cm from counter electrode. Particles were then characterized using FESEM and average size of electrosprayed particles obtained. Initial droplet size was calculated by scaling law and compared with FE-SEM results in order to prove droplet fission occur during electrospray. Due to the results obtained, as the working distance increase from 10–20 cm the deposited TiO2 droplet size decrease from 247–116 nm to show droplet fission occur during the experiment.

Nano-order particles have recently being utilized for uniform surface coating and thin film production in food, biomedical and pharmaceutical applications due to their high specific surface area. In this study, production of nano-order particles from Zinc Oxide (ZnO) powder using electrospray method was developed. ZnO suspensions of different pH were prepared by dispersing ZnO powder in distilled water followed by sonication. The zeta potential value and particle size distribution of the prepared ZnO suspensions were in the range of-17 to -53 mV and 104-197 nm respectively. Electrosprayed ZnO suspensions were maintained under Taylor cone mode by manipulating the voltage supply in order to obtain stable and monodisperse droplets. Scaling law models were used to determine the theoretical mean droplet size based on conductivity value of the suspensions. The collected droplets were analyzed visually with scanning electron microscope (SEM). The results showed that mean droplet size obtained from this experiment was smaller than the theoretical ones and strongly dependent on suspension conductivity. Findings of the present study also confirmed that electrospray is a promising approach for producing nano-order particles.

Nano-order particles have recently being utilized for uniform surface coating and thin film production in food, biomedical and pharmaceutical applications due to their high specific surface area. In this study, production of nano-order particles from Zinc Oxide (ZnO) powder using electrospray method was developed. ZnO suspensions of different pH were prepared by dispersing ZnO powder in distilled water followed by sonication. The zeta potential value and particle size distribution of the prepared ZnO suspensions were in the range of-17 to -53 mV and 104-197 nm respectively. Electrosprayed ZnO suspensions were maintained under Taylor cone mode by manipulating the voltage supply in order to obtain stable and monodisperse droplets. Scaling law models were used to determine the theoretical mean droplet size based on conductivity value of the suspensions. The collected droplets were analyzed visually with scanning electron microscope (SEM). The results showed that mean droplet size obtained from this experiment was smaller than the theoretical ones and strongly dependent on suspension conductivity. Findings of the present study also confirmed that electrospray is a promising approach for producing nano-order particles.