Survival, oxidative stability, and surface characteristics of spray dried co-microcapsules containing omega-3 fatty acids and probiotic bacteria
- Eratte, Divya, Gengenbach, Thomas, Dowling, Kim, Barrow, Colin, Adhikari, Benu
- Authors: Eratte, Divya , Gengenbach, Thomas , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Drying Technology Vol. 34, no. 16 (2016), p. 1926-1935
- Full Text:
- Reviewed:
- Description: The objective of the study was to determine optimum inlet and outlet air temperatures of spray process for producing co-microcapsules containing omega-3 rich tuna oil and probiotic bacteria L. casei. These co-microcapsules were produced using whey protein isolate and gum Arabic complex coacervates as shell materials. Improved bacterial viability and oxidative stability of omega-3 oil were used as two main criteria of this study. Three sets of inlet (130 degrees C, 150 degrees C, and 170 degrees C) and outlet (55 degrees C, 65 degrees C, and 75 degrees C) air temperatures were used in nine combinations to produce powdered co-microcapsule. The viability of L. casei, oxidative stability of omega-3 oil, surface oil, oil microencapsulation efficiency, moisture content, surface elemental composition and morphology of the powdered samples were measured. There is no statistical difference in oxidative stability at two lower inlet air temperatures (130 degrees C and 150 degrees C). However, there was a significant decrease in oxidative stability when higher inlet temperature (170 degrees C) was used. The viability of L. casei decreased with the increase in the inlet and outlet air temperatures. There was no difference in the surface elemental compositions and surface morphology of powdered co-microcapsules produced under these nine inlet/outlet temperature combinations. Of the range of conditions tested the co-microcapsules produced at inlet-outlet temperature 130-65 degrees C showed the highest bacterial viability and oxidative stability of omega-3 and having the moisture content of 4.93 +/- 0.05% (w/w). This research shows that powdered co-microcapsules of probiotic bacteria and omega-3 fatty acids with high survival of the former and high stability against oxidation can be produced through spray drying.
- Authors: Eratte, Divya , Gengenbach, Thomas , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Drying Technology Vol. 34, no. 16 (2016), p. 1926-1935
- Full Text:
- Reviewed:
- Description: The objective of the study was to determine optimum inlet and outlet air temperatures of spray process for producing co-microcapsules containing omega-3 rich tuna oil and probiotic bacteria L. casei. These co-microcapsules were produced using whey protein isolate and gum Arabic complex coacervates as shell materials. Improved bacterial viability and oxidative stability of omega-3 oil were used as two main criteria of this study. Three sets of inlet (130 degrees C, 150 degrees C, and 170 degrees C) and outlet (55 degrees C, 65 degrees C, and 75 degrees C) air temperatures were used in nine combinations to produce powdered co-microcapsule. The viability of L. casei, oxidative stability of omega-3 oil, surface oil, oil microencapsulation efficiency, moisture content, surface elemental composition and morphology of the powdered samples were measured. There is no statistical difference in oxidative stability at two lower inlet air temperatures (130 degrees C and 150 degrees C). However, there was a significant decrease in oxidative stability when higher inlet temperature (170 degrees C) was used. The viability of L. casei decreased with the increase in the inlet and outlet air temperatures. There was no difference in the surface elemental compositions and surface morphology of powdered co-microcapsules produced under these nine inlet/outlet temperature combinations. Of the range of conditions tested the co-microcapsules produced at inlet-outlet temperature 130-65 degrees C showed the highest bacterial viability and oxidative stability of omega-3 and having the moisture content of 4.93 +/- 0.05% (w/w). This research shows that powdered co-microcapsules of probiotic bacteria and omega-3 fatty acids with high survival of the former and high stability against oxidation can be produced through spray drying.
Complex coacervation between flaxseed protein isolate and flaxseed gum
- Kaushik, Pratibha, Dowling, Kim, Barrow, Colin, Adhikari, Benu
- Authors: Kaushik, Pratibha , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Food Research International Vol. 72, no. (2015), p. 91-97
- Full Text:
- Reviewed:
- Description:
Flaxseed protein isolate (FPI) and flaxseed gum (FG) were extracted, and the electrostatic complexation between these two biopolymers was studied as a function of pH and FPI-to-FG ratio using turbidimetric and electrophoretic mobility (zeta potential) tests. The zeta potential values of FPI, FG, and their mixtures at the FPI-to-FG ratios of 1:1, 3:1, 5:1, 10:1, 15:1 were measured over a pH range 8.0-1.5. The alteration of the secondary structure of FPI as a function of pH was studied using circular dichroism. The proportion of a-helical structure decreased, whereas both β-sheet structure and random coil structure increased with the lowering of pH from 8.0 to 3.0. The acidic pH affected the secondary structure of FPI and the unfolding of helix conformation facilitated the complexation of FPI with FG. The optimum FPI-to-FG ratio for complex coacervation was found to be 3:1. The critical pH values associated with the formation of soluble (pHc) and insoluble (pH
Φ1 ) complexes at the optimum FPI-to-FG ratio were found to be 6.0 and 4.5, respectively. The optimum pH (pHopt ) for the optimum complex coacervation was 3.1. The instability and dissolution of FPI-FG complex coacervates started (pHΦ2 ) at pH2.1. These findings contribute to the development of FPI-FG complex coacervates as delivery vehicles for unstable albeit valuable nutrients such as omega-3 fatty acids. © 2015.
- Authors: Kaushik, Pratibha , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Food Research International Vol. 72, no. (2015), p. 91-97
- Full Text:
- Reviewed:
- Description:
Flaxseed protein isolate (FPI) and flaxseed gum (FG) were extracted, and the electrostatic complexation between these two biopolymers was studied as a function of pH and FPI-to-FG ratio using turbidimetric and electrophoretic mobility (zeta potential) tests. The zeta potential values of FPI, FG, and their mixtures at the FPI-to-FG ratios of 1:1, 3:1, 5:1, 10:1, 15:1 were measured over a pH range 8.0-1.5. The alteration of the secondary structure of FPI as a function of pH was studied using circular dichroism. The proportion of a-helical structure decreased, whereas both β-sheet structure and random coil structure increased with the lowering of pH from 8.0 to 3.0. The acidic pH affected the secondary structure of FPI and the unfolding of helix conformation facilitated the complexation of FPI with FG. The optimum FPI-to-FG ratio for complex coacervation was found to be 3:1. The critical pH values associated with the formation of soluble (pHc) and insoluble (pH
Φ1 ) complexes at the optimum FPI-to-FG ratio were found to be 6.0 and 4.5, respectively. The optimum pH (pHopt ) for the optimum complex coacervation was 3.1. The instability and dissolution of FPI-FG complex coacervates started (pHΦ2 ) at pH2.1. These findings contribute to the development of FPI-FG complex coacervates as delivery vehicles for unstable albeit valuable nutrients such as omega-3 fatty acids. © 2015.
Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films
- Muscat, Delina, Adhikari, Raju, Tobin, Mark, McKnight, Stafford, Wakeling, Lara, Adhikari, Benu
- Authors: Muscat, Delina , Adhikari, Raju , Tobin, Mark , McKnight, Stafford , Wakeling, Lara , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 111, no. (2014), p. 333-347
- Full Text:
- Reviewed:
- Description: This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG + wax + PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface. © 2014 Elsevier Ltd.
- Authors: Muscat, Delina , Adhikari, Raju , Tobin, Mark , McKnight, Stafford , Wakeling, Lara , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 111, no. (2014), p. 333-347
- Full Text:
- Reviewed:
- Description: This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG + wax + PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface. © 2014 Elsevier Ltd.
Survival, fermentation activity and storage stability of spray dried Lactococcus lactis produced via different atomization regimes
- Ghandi, Amir, Powell, Ian, Broome, Melcolm, Adhikari, Benu
- Authors: Ghandi, Amir , Powell, Ian , Broome, Melcolm , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 115, no. 1 (2013), p. 83-90
- Full Text:
- Reviewed:
- Description: Dried powders containing Lactococcus lactis ssp. cremoris were produced using laboratory and pilot scale spray dryers with lactose:whey protein isolate (3:1) as a protective medium. The effects of storage temperature (25, 4 and -18 °C) and time (30, 60 and 90 days) were studied. The survival and fermentation activity of the dried bacterial cells were significantly lower when the powders were stored at 25 °C compared to those stored at 4 and -18 °C; powders stored at 4 and -18 °C were statistically similar. The survival and fermentation activity of bacterial cells obtained from a laboratory scale two-fluid nozzle spray dryer were found to be higher than those of cells obtained from a pilot scale two-fluid spray dryer. A rotary wheel atomizer gave significantly higher survival and activity in the same dryer. These observations are consistent with cell damage due to high characteristic shear rates in the atomization process in nozzle type atomizers. The presence of ascorbic acid (oxygen scavenger) in the powder composition was found to improve both the survival and the maintenance of fermentation activity of the dried bacterial cells significantly during storage. The survival and fermentation activity of dried bacterial cells in stored powders indicated that these parameters are system-specific and can be strongly affected by the storage temperature and presence or absence of antioxidant, and also by upstream processing conditions such as the mode of atomization and presence or absence of antioxidants in the dryer feed. © 2012 Elsevier Ltd. All rights reserved.
- Description: 2003010581
- Authors: Ghandi, Amir , Powell, Ian , Broome, Melcolm , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 115, no. 1 (2013), p. 83-90
- Full Text:
- Reviewed:
- Description: Dried powders containing Lactococcus lactis ssp. cremoris were produced using laboratory and pilot scale spray dryers with lactose:whey protein isolate (3:1) as a protective medium. The effects of storage temperature (25, 4 and -18 °C) and time (30, 60 and 90 days) were studied. The survival and fermentation activity of the dried bacterial cells were significantly lower when the powders were stored at 25 °C compared to those stored at 4 and -18 °C; powders stored at 4 and -18 °C were statistically similar. The survival and fermentation activity of bacterial cells obtained from a laboratory scale two-fluid nozzle spray dryer were found to be higher than those of cells obtained from a pilot scale two-fluid spray dryer. A rotary wheel atomizer gave significantly higher survival and activity in the same dryer. These observations are consistent with cell damage due to high characteristic shear rates in the atomization process in nozzle type atomizers. The presence of ascorbic acid (oxygen scavenger) in the powder composition was found to improve both the survival and the maintenance of fermentation activity of the dried bacterial cells significantly during storage. The survival and fermentation activity of dried bacterial cells in stored powders indicated that these parameters are system-specific and can be strongly affected by the storage temperature and presence or absence of antioxidant, and also by upstream processing conditions such as the mode of atomization and presence or absence of antioxidants in the dryer feed. © 2012 Elsevier Ltd. All rights reserved.
- Description: 2003010581
The survival of lactococcus lactis in a convective-air-drying environment: The role of protectant solids, oxygen injury, and mechanism of protection
- Ghandi, Amir, Powell, Ian, Chen, Xiao Dong, Adhikari, Benu
- Authors: Ghandi, Amir , Powell, Ian , Chen, Xiao Dong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 13-14 (2013), p. 1661-1674
- Full Text:
- Reviewed:
- Description: The effect of protectant solids (lactose, sodium caseinate, and their mixture) on the survival of Lactococcus lactis subsp. cremoris was studied in a convective-air-drying environment using single droplet drying. The effect of drying the bacteria in the presence or absence of sodium ascorbate was evaluated, and the evolution of glass transition temperature in the drying process was examined. It was found that the protective efficiency of lactose and sodium caseinate was comparable at the concentrations tested. A mixed protectant matrix (lactose:sodium caseinate, 3:1) gave higher survival than with lactose or sodium caseinate alone at the same total solids level. Protectants enhanced bacterial survival by moderating the drying rate and achieving dryness at lower temperatures, and by facilitating the formation of a glassy matrix earlier in the drying process. The addition of sodium ascorbate was also examined. © 2013 Copyright Taylor and Francis Group, LLC.
- Description: C1
- Authors: Ghandi, Amir , Powell, Ian , Chen, Xiao Dong , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 13-14 (2013), p. 1661-1674
- Full Text:
- Reviewed:
- Description: The effect of protectant solids (lactose, sodium caseinate, and their mixture) on the survival of Lactococcus lactis subsp. cremoris was studied in a convective-air-drying environment using single droplet drying. The effect of drying the bacteria in the presence or absence of sodium ascorbate was evaluated, and the evolution of glass transition temperature in the drying process was examined. It was found that the protective efficiency of lactose and sodium caseinate was comparable at the concentrations tested. A mixed protectant matrix (lactose:sodium caseinate, 3:1) gave higher survival than with lactose or sodium caseinate alone at the same total solids level. Protectants enhanced bacterial survival by moderating the drying rate and achieving dryness at lower temperatures, and by facilitating the formation of a glassy matrix earlier in the drying process. The addition of sodium ascorbate was also examined. © 2013 Copyright Taylor and Francis Group, LLC.
- Description: C1
Drying kinetics and survival studies of dairy fermentation bacteria in convective air drying environment using single droplet drying
- Ghandi, Amir, Powell, Ian, Chen, Xiao Dong, Adhikari, Benu
- Authors: Ghandi, Amir , Powell, Ian , Chen, Xiao Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 110, no. 3 (2012), p. 405-417
- Full Text:
- Reviewed:
- Description: The drying and survival kinetics of Lactococcus lactis ssp. cremoris in a convective air drying environment were measured using single droplet drying experiments. Tests were carried out at five different drying temperatures (45-95°C) at a constant air velocity (0.5 m/s) and within 2.4-11% relative humidity. The effect of protective agents (10% w/w) of lactose, sodium caseinate and lactose:sodium caseinate (3:1) was also evaluated. The thermal inactivation kinetics parameters in convective air drying and isothermal water bath heating were determined and compared. The results showed that the final temperature attained by the droplet affected the survival of the bacteria significantly, however, most of the bacterial death occurred in early stage of drying while evaporative cooling kept the drop temperature relatively low. At higher droplet temperatures (≥65°C) the bacterial cultures were inactivated by both dehydration and thermal stresses. At lower droplet temperatures (≤55°C) the rate of change in droplet moisture content had much stronger effect on the bacterial survival. Lactose and sodium caseinate, as protective agents, enhanced the survival of bacterial cells significantly at all the test conditions. The lactose:sodium caseinate (3:1) mixture synergistically enhanced the survival of the bacterial cultures. The death of these bacteria followed first-order kinetics during convective single droplet drying as well as during isothermal water-bath heating. However, the inactivation energy in convective single droplet drying (181.3 kJ/mol) was much higher than the inactivation energy in isothermal water bath heating (16.8 kJ/mol) within the medium temperature of 45-95°C. © 2012 Elsevier Ltd. All rights reserved.
- Authors: Ghandi, Amir , Powell, Ian , Chen, Xiao Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 110, no. 3 (2012), p. 405-417
- Full Text:
- Reviewed:
- Description: The drying and survival kinetics of Lactococcus lactis ssp. cremoris in a convective air drying environment were measured using single droplet drying experiments. Tests were carried out at five different drying temperatures (45-95°C) at a constant air velocity (0.5 m/s) and within 2.4-11% relative humidity. The effect of protective agents (10% w/w) of lactose, sodium caseinate and lactose:sodium caseinate (3:1) was also evaluated. The thermal inactivation kinetics parameters in convective air drying and isothermal water bath heating were determined and compared. The results showed that the final temperature attained by the droplet affected the survival of the bacteria significantly, however, most of the bacterial death occurred in early stage of drying while evaporative cooling kept the drop temperature relatively low. At higher droplet temperatures (≥65°C) the bacterial cultures were inactivated by both dehydration and thermal stresses. At lower droplet temperatures (≤55°C) the rate of change in droplet moisture content had much stronger effect on the bacterial survival. Lactose and sodium caseinate, as protective agents, enhanced the survival of bacterial cells significantly at all the test conditions. The lactose:sodium caseinate (3:1) mixture synergistically enhanced the survival of the bacterial cultures. The death of these bacteria followed first-order kinetics during convective single droplet drying as well as during isothermal water-bath heating. However, the inactivation energy in convective single droplet drying (181.3 kJ/mol) was much higher than the inactivation energy in isothermal water bath heating (16.8 kJ/mol) within the medium temperature of 45-95°C. © 2012 Elsevier Ltd. All rights reserved.
Effect of shear rate and oxygen stresses on the survival of Lactococcus lactis during the atomization and drying stages of spray drying : A laboratory and pilot scale study
- Ghandi, Amir, Powell, Ian, Howes, Tony, Chen, Xiao Dong, Adhikari, Benu
- Authors: Ghandi, Amir , Powell, Ian , Howes, Tony , Chen, Xiao Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 113, no. 2 (2012), p. 194-200
- Full Text:
- Reviewed:
- Description: The effect of shear rate and oxygen injury during atomization and the combination of these factors on the survival of Lactococcus lactis subsp. cremoris in spray drying was studied using laboratory and pilot scale spray dryers. The atomization was carried out using a two-fluid nozzle in the laboratory study and a two-fluid nozzle or rotary atomizer in the pilot scale study. The extent of oxygen-induced death was determined using ascorbic acid in the feed and atomizing the feed with gaseous nitrogen. The lowest levels of bacterial death were observed at lowest characteristic shear rate and in the presence of nitrogen and ascorbic acid. Quantitative analysis showed that lower shear rate, creating an oxygen-limiting environment during atomization and drying, and using oxygen scavengers in the feed were successful in enhancing bacterial survival in spray drying. We also report for the first time that, at least for L. lactis, the extent of death during the atomization stage far outweighs death during the drying stage, and that the majority of bacterial death (up to 93%) occurs during the atomization stage. The death of bacteria was found to be less when using a rotary atomizer or when using a two-fluid nozzle atomizer at lower flow rate. This work shows that bacterial death during spray drying can be minimized by using oxygen scavengers such as ascorbic acid and/or an anaerobic atomizing medium (such as nitrogen), and by altering the spraying conditions. © 2012 Elsevier Ltd. All rights reserved.
- Authors: Ghandi, Amir , Powell, Ian , Howes, Tony , Chen, Xiao Dong , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 113, no. 2 (2012), p. 194-200
- Full Text:
- Reviewed:
- Description: The effect of shear rate and oxygen injury during atomization and the combination of these factors on the survival of Lactococcus lactis subsp. cremoris in spray drying was studied using laboratory and pilot scale spray dryers. The atomization was carried out using a two-fluid nozzle in the laboratory study and a two-fluid nozzle or rotary atomizer in the pilot scale study. The extent of oxygen-induced death was determined using ascorbic acid in the feed and atomizing the feed with gaseous nitrogen. The lowest levels of bacterial death were observed at lowest characteristic shear rate and in the presence of nitrogen and ascorbic acid. Quantitative analysis showed that lower shear rate, creating an oxygen-limiting environment during atomization and drying, and using oxygen scavengers in the feed were successful in enhancing bacterial survival in spray drying. We also report for the first time that, at least for L. lactis, the extent of death during the atomization stage far outweighs death during the drying stage, and that the majority of bacterial death (up to 93%) occurs during the atomization stage. The death of bacteria was found to be less when using a rotary atomizer or when using a two-fluid nozzle atomizer at lower flow rate. This work shows that bacterial death during spray drying can be minimized by using oxygen scavengers such as ascorbic acid and/or an anaerobic atomizing medium (such as nitrogen), and by altering the spraying conditions. © 2012 Elsevier Ltd. All rights reserved.
Interfacial and emulsifying properties of lentil protein isolate
- Joshi, Matina, Adhikari, Benu, Aldred, Peter, Panozzo, Joe, Kasapis, Stefan, Barrow, Colin
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan , Barrow, Colin
- Date: 2012
- Type: Text , Journal article
- Relation: Food Chemistry Vol.134 no.3 (2012), p.343-1353
- Full Text:
- Reviewed:
- Description: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas > LPI > WPI > BSA > Lys, while their surface hydrophobicity was in the following order: BSA > LPI > NaCas > WPI > Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m 2/g and it was 93.3 ± 0.2 m 2/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents. © 2012 Elsevier Ltd. All rights reserved.
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan , Barrow, Colin
- Date: 2012
- Type: Text , Journal article
- Relation: Food Chemistry Vol.134 no.3 (2012), p.343-1353
- Full Text:
- Reviewed:
- Description: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas > LPI > WPI > BSA > Lys, while their surface hydrophobicity was in the following order: BSA > LPI > NaCas > WPI > Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m 2/g and it was 93.3 ± 0.2 m 2/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents. © 2012 Elsevier Ltd. All rights reserved.
The effect of protein types and low molecular weight surfactants on spray drying of sugar-rich foods
- Jayasundera, Mithila, Adhikari, Benu, Adhikari, Raju, Aldred, Peter
- Authors: Jayasundera, Mithila , Adhikari, Benu , Adhikari, Raju , Aldred, Peter
- Date: 2010
- Type: Text , Journal article
- Relation: Food Hydrocolloids Vol. 25, no. 3 (2010), p. 459-469
- Full Text:
- Reviewed:
- Description: The effect of protein types and low molecular weight surfactants (LMS) on spray drying of sugar-rich foods has been studied using sucrose as a model sugar and sodium caseinate (NaCas) and pea protein isolate (PPI) as model proteins. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween-80) were chosen as model ionic and non-ionic LMS. The sucrose:NaCas and sucrose:PPI solid ratios were maintained at (99.5:0.5) and (99:1), respectively and spray-dried maintaining 25% solids in feed solutions. It was found that the proteins preferentially migrated to the air-water interface reasonably swiftly and the addition of LMS resulted into partial or complete displacement of the proteins from the air-water interface. More than 80% of amorphous sucrose powder was produced with the addition of 0.13% (w/w) of NaCas in feed solution. PPI was not as effective and produced less than 50% recovery even at 0.26% (w/w) in feed. Addition of 0.01-0.05% SSL displaced 2.0% and 29.3% of proteins from the surface of sucrose-NaCas-SSL droplet, respectively, resulting in a 6.5 ± 1.2% to 51.9 ± 1.9% reduction in powder recovery. The extent of protein displacement was higher when SSL was added into sucrose-PPI solution; however, the powder recovery was not much affected. The addition of 0.01% Tween-80 in sucrose-NaCas solution resulted in a 48.2 ± 1.5% reduction in powder recovery and at 0.05% concentration, it displaced a substantial amount or all the NaCas from the droplet surface and no powder was recovered. The addition of 0.01% and 0.05% Tween-80 into sucrose-PPI solution resulted into very low powder recoveries (24.9 ± 0.4% and 29.5 ± 1.8%, respectively). The glass transition temperature (Tg) results revealed that the amount of protein required for successful spray drying of sucrose-protein solutions depends on the amount of proteins present on the droplet surface but not on the bulk concentration. X-ray diffraction and scanning electron microscopy results showed that the powders of sucrose-NaCas/PPI and sucrose-NaCas/PPI with 0.01% SSL were mostly amorphous while those with sucrose-NaCas/PPI-Tween-80 (0.01%), sucrose-PPI-Tween-80 (0.05%) and sucrose-NaCas/PPI-SSL (0.05%) were crystalline. © 2010 Elsevier Ltd. All rights reserved.
The effect of protein types and low molecular weight surfactants on spray drying of sugar-rich foods
- Authors: Jayasundera, Mithila , Adhikari, Benu , Adhikari, Raju , Aldred, Peter
- Date: 2010
- Type: Text , Journal article
- Relation: Food Hydrocolloids Vol. 25, no. 3 (2010), p. 459-469
- Full Text:
- Reviewed:
- Description: The effect of protein types and low molecular weight surfactants (LMS) on spray drying of sugar-rich foods has been studied using sucrose as a model sugar and sodium caseinate (NaCas) and pea protein isolate (PPI) as model proteins. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween-80) were chosen as model ionic and non-ionic LMS. The sucrose:NaCas and sucrose:PPI solid ratios were maintained at (99.5:0.5) and (99:1), respectively and spray-dried maintaining 25% solids in feed solutions. It was found that the proteins preferentially migrated to the air-water interface reasonably swiftly and the addition of LMS resulted into partial or complete displacement of the proteins from the air-water interface. More than 80% of amorphous sucrose powder was produced with the addition of 0.13% (w/w) of NaCas in feed solution. PPI was not as effective and produced less than 50% recovery even at 0.26% (w/w) in feed. Addition of 0.01-0.05% SSL displaced 2.0% and 29.3% of proteins from the surface of sucrose-NaCas-SSL droplet, respectively, resulting in a 6.5 ± 1.2% to 51.9 ± 1.9% reduction in powder recovery. The extent of protein displacement was higher when SSL was added into sucrose-PPI solution; however, the powder recovery was not much affected. The addition of 0.01% Tween-80 in sucrose-NaCas solution resulted in a 48.2 ± 1.5% reduction in powder recovery and at 0.05% concentration, it displaced a substantial amount or all the NaCas from the droplet surface and no powder was recovered. The addition of 0.01% and 0.05% Tween-80 into sucrose-PPI solution resulted into very low powder recoveries (24.9 ± 0.4% and 29.5 ± 1.8%, respectively). The glass transition temperature (Tg) results revealed that the amount of protein required for successful spray drying of sucrose-protein solutions depends on the amount of proteins present on the droplet surface but not on the bulk concentration. X-ray diffraction and scanning electron microscopy results showed that the powders of sucrose-NaCas/PPI and sucrose-NaCas/PPI with 0.01% SSL were mostly amorphous while those with sucrose-NaCas/PPI-Tween-80 (0.01%), sucrose-PPI-Tween-80 (0.05%) and sucrose-NaCas/PPI-SSL (0.05%) were crystalline. © 2010 Elsevier Ltd. All rights reserved.
Effect of addition of proteins on the production of amorphous sucrose powder through spray drying
- Adhikari, Benu, Howes, Tony, Bhandari, Bhesh, Langrish, Tim
- Authors: Adhikari, Benu , Howes, Tony , Bhandari, Bhesh , Langrish, Tim
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 94, no. 2 (2009), p. 144 -153
- Full Text:
- Reviewed:
- Description: Spray drying trials were carried out to produce amorphous sucrose powder. Firstly, pure sucrose solutions were prepared and spray dried at inlet and outlet temperatures of 160 °C and 70 °C, respectively. No amorphous powder was obtained and only 18% of the feed solids were recovered in a crystalline form, with the remaining solids lost as wall deposits. Secondly, sodium caseinate (Na-C) and hydrolyzed whey protein isolate (WPI) were added in sucrose:protein solid ratios of (99.5:0.5) and (99.0:1.0) and drying trials were conducted maintaining the initial drying conditions. In both these cases, greater than 80% of the feed solids were recovered in an amorphous form. The increase in protein concentration from 0.5% to 1% on dry solid basis did not further improve the recovery. The remarkable increase in recovery from a small addition of protein is attributed to preferential migration of protein molecules to the droplet-air interface, and the subsequent transformation of the thin, protein-rich film into a non-sticky glassy state upon drying. This film overcomes both the particle-to-particle and particle-to-wall stickiness. The measured bulk glass rubber transition temperature (Tg-r) values of the bulk mixtures at various moisture contents were very close to the corresponding mean glass transition temperature (Tg) of the pure sucrose indicating that surface layer Tg rather than the bulk Tg is responsible for this. Electron spectroscopy for chemical analysis (ESCA) studies revealed that the particle surface was covered by 50-58% (by mass) proteins. The calculated glass transition temperature of the surface layer (Tg,surface layer), based on the surface elemental compositions, showed that the Tg,surface layer has increased to the extent that it remained within the safe drying envelope of spray drying. © 2009 Elsevier Ltd. All rights reserved.
- Authors: Adhikari, Benu , Howes, Tony , Bhandari, Bhesh , Langrish, Tim
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 94, no. 2 (2009), p. 144 -153
- Full Text:
- Reviewed:
- Description: Spray drying trials were carried out to produce amorphous sucrose powder. Firstly, pure sucrose solutions were prepared and spray dried at inlet and outlet temperatures of 160 °C and 70 °C, respectively. No amorphous powder was obtained and only 18% of the feed solids were recovered in a crystalline form, with the remaining solids lost as wall deposits. Secondly, sodium caseinate (Na-C) and hydrolyzed whey protein isolate (WPI) were added in sucrose:protein solid ratios of (99.5:0.5) and (99.0:1.0) and drying trials were conducted maintaining the initial drying conditions. In both these cases, greater than 80% of the feed solids were recovered in an amorphous form. The increase in protein concentration from 0.5% to 1% on dry solid basis did not further improve the recovery. The remarkable increase in recovery from a small addition of protein is attributed to preferential migration of protein molecules to the droplet-air interface, and the subsequent transformation of the thin, protein-rich film into a non-sticky glassy state upon drying. This film overcomes both the particle-to-particle and particle-to-wall stickiness. The measured bulk glass rubber transition temperature (Tg-r) values of the bulk mixtures at various moisture contents were very close to the corresponding mean glass transition temperature (Tg) of the pure sucrose indicating that surface layer Tg rather than the bulk Tg is responsible for this. Electron spectroscopy for chemical analysis (ESCA) studies revealed that the particle surface was covered by 50-58% (by mass) proteins. The calculated glass transition temperature of the surface layer (Tg,surface layer), based on the surface elemental compositions, showed that the Tg,surface layer has increased to the extent that it remained within the safe drying envelope of spray drying. © 2009 Elsevier Ltd. All rights reserved.
Surface modification of spray dried food and emulsion powders with surface-active proteins : A review
- Jayasundera, Mithila, Adhikari, Benu, Aldred, Peter, Ghandi, Amir
- Authors: Jayasundera, Mithila , Adhikari, Benu , Aldred, Peter , Ghandi, Amir
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 93, no. 3 (2009), p. 266-277
- Full Text:
- Reviewed:
- Description: Spray drying is a well-established and widely used method for transforming a wide range of liquid food products into powder form. Stickiness is the limitation in spray drying of different sugar and acid-rich food products. To minimize this problem process and material science based approaches are in place. However, these remedies have their own drawbacks. Surface modification of droplets/particles is a novel way to minimize stickiness. It is timely that the research efforts on surface modification of droplets/particles be reviewed. Therefore, this review highlights the recent research dealing with surface modification of emulsions and spray dried powders. The theoretical foundation, mechanisms and methods used to achieve surface modification of food and emulsion powders are highlighted. © 2009 Elsevier Ltd. All rights reserved.
- Authors: Jayasundera, Mithila , Adhikari, Benu , Aldred, Peter , Ghandi, Amir
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 93, no. 3 (2009), p. 266-277
- Full Text:
- Reviewed:
- Description: Spray drying is a well-established and widely used method for transforming a wide range of liquid food products into powder form. Stickiness is the limitation in spray drying of different sugar and acid-rich food products. To minimize this problem process and material science based approaches are in place. However, these remedies have their own drawbacks. Surface modification of droplets/particles is a novel way to minimize stickiness. It is timely that the research efforts on surface modification of droplets/particles be reviewed. Therefore, this review highlights the recent research dealing with surface modification of emulsions and spray dried powders. The theoretical foundation, mechanisms and methods used to achieve surface modification of food and emulsion powders are highlighted. © 2009 Elsevier Ltd. All rights reserved.
The effect of low molecular weight surfactants and proteins on surface stickiness of sucrose during powder formation through spray drying
- Adhikari, Benu, Howes, Tony, Wood, B. J., Bhandari, Bhesh
- Authors: Adhikari, Benu , Howes, Tony , Wood, B. J. , Bhandari, Bhesh
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 94, no. 2 (2009), p. 135 -143
- Full Text:
- Reviewed:
- Description: The effect of competitive surface migration of proteins and low molecular weight surfactants (LMS) on the powder recovery in spray drying of highly sticky sugar-rich food has been studied. Sucrose was chosen as a model sugar-rich food because it cannot be easily converted into a pure amorphous powder through spray drying. Sodium caseinate (Na-C) and hydrolyzed whey protein isolate (WPI) were used as model proteins. Polysorbate 80 (Tween-80) and sodium dodecyl sulfate (Na-DS) were used as model non-ionic and ionic LMS. A sucrose solution was spray dried without any additives to establish a base case. Following this, spray drying trials of sucrose-protein solutions were conducted. The sucrose: protein ratio was maintained at 99.5:0.5 and 99.0:1.0. Finally, 0.05% of Tween-80 and Na-DS, on a nominal feed basis, were individually added to the solutions and spray dried. The solid concentration of all of the feed solutions was set at 25% and the inlet and outlet temperatures were maintained at 170 °C and 70 °C, respectively. Powder recovery was determined using a standard procedure and taken as an indicator of the surface stickiness. Coverage of the particle surface by the proteins was determined through elemental surface analysis and a nitrogen balance. It was found that in the absence of LMS, the proteins covered up to 55% of the particle surface and increased the powder recovery to between 84% and 85%. Formation of a glassy protein-rich film acts to reduce the surface stickiness of sucrose droplets. However, when LMS was added to the sucrose-protein solutions, the recovery dropped to zero in the case of Tween-80. In the case of Na-DS the recoveries ranged to 39% and 68%. At these recoveries 83% and 59% of the protein, respectively, was displaced from the surface. This drastic effect of surfactant types on the powder recovery is explained using the Orogenic Displacement model. © 2009 Elsevier Ltd. All rights reserved.
- Authors: Adhikari, Benu , Howes, Tony , Wood, B. J. , Bhandari, Bhesh
- Date: 2009
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 94, no. 2 (2009), p. 135 -143
- Full Text:
- Reviewed:
- Description: The effect of competitive surface migration of proteins and low molecular weight surfactants (LMS) on the powder recovery in spray drying of highly sticky sugar-rich food has been studied. Sucrose was chosen as a model sugar-rich food because it cannot be easily converted into a pure amorphous powder through spray drying. Sodium caseinate (Na-C) and hydrolyzed whey protein isolate (WPI) were used as model proteins. Polysorbate 80 (Tween-80) and sodium dodecyl sulfate (Na-DS) were used as model non-ionic and ionic LMS. A sucrose solution was spray dried without any additives to establish a base case. Following this, spray drying trials of sucrose-protein solutions were conducted. The sucrose: protein ratio was maintained at 99.5:0.5 and 99.0:1.0. Finally, 0.05% of Tween-80 and Na-DS, on a nominal feed basis, were individually added to the solutions and spray dried. The solid concentration of all of the feed solutions was set at 25% and the inlet and outlet temperatures were maintained at 170 °C and 70 °C, respectively. Powder recovery was determined using a standard procedure and taken as an indicator of the surface stickiness. Coverage of the particle surface by the proteins was determined through elemental surface analysis and a nitrogen balance. It was found that in the absence of LMS, the proteins covered up to 55% of the particle surface and increased the powder recovery to between 84% and 85%. Formation of a glassy protein-rich film acts to reduce the surface stickiness of sucrose droplets. However, when LMS was added to the sucrose-protein solutions, the recovery dropped to zero in the case of Tween-80. In the case of Na-DS the recoveries ranged to 39% and 68%. At these recoveries 83% and 59% of the protein, respectively, was displaced from the surface. This drastic effect of surfactant types on the powder recovery is explained using the Orogenic Displacement model. © 2009 Elsevier Ltd. All rights reserved.
The impact of various drying kinetics models on the prediction of sample temperature-time and moisture content-time profiles during moisture removal from stratum corneum
- Kar, S., Chen, Xiao Dong, Adhikari, Benu, Lin, S. X. Q.
- Authors: Kar, S. , Chen, Xiao Dong , Adhikari, Benu , Lin, S. X. Q.
- Date: 2009
- Type: Text , Journal article
- Relation: Chemical Engineering Research and Design Vol. 87, no. 5 (2009), p. 739-755
- Full Text:
- Reviewed:
- Description: An attempt has been made here to model the moisture transport kinetics across porcine stratum corneum. Samples of porcine skin were dissected in the form of 'thin layers' (i.e. stratum corneum) of dimensions of 11.3 × 11.3 mm (70-200 μm thick). These layers were dried in a laboratory convection air dryer at 37 °C (normal human body temperature). The changes in weights of the samples were noted. The weight loss data was then converted in terms of moisture content (dry basis) and were monitored over time. Thereafter they were fitted against an empirical equation notably the Page model (Model 1) and the solution generated by the Fickian diffusion equation (Model 2). The current paper demonstrates the effectiveness of these two models in prediction of the sample temperature during drying. Furthermore, it also demonstrates the variation in spatial distribution of moisture content within the skin sample when moisture content and temperature dependency are introduced in the diffusivity. Such findings are important especially when developing skin multi-compartment physiologically based pharmacokinetic (PBPK) models to assess transdermal permeation of various hydrophilic penetrants. © 2008 The Institution of Chemical Engineers.
- Description: 2003006794
- Authors: Kar, S. , Chen, Xiao Dong , Adhikari, Benu , Lin, S. X. Q.
- Date: 2009
- Type: Text , Journal article
- Relation: Chemical Engineering Research and Design Vol. 87, no. 5 (2009), p. 739-755
- Full Text:
- Reviewed:
- Description: An attempt has been made here to model the moisture transport kinetics across porcine stratum corneum. Samples of porcine skin were dissected in the form of 'thin layers' (i.e. stratum corneum) of dimensions of 11.3 × 11.3 mm (70-200 μm thick). These layers were dried in a laboratory convection air dryer at 37 °C (normal human body temperature). The changes in weights of the samples were noted. The weight loss data was then converted in terms of moisture content (dry basis) and were monitored over time. Thereafter they were fitted against an empirical equation notably the Page model (Model 1) and the solution generated by the Fickian diffusion equation (Model 2). The current paper demonstrates the effectiveness of these two models in prediction of the sample temperature during drying. Furthermore, it also demonstrates the variation in spatial distribution of moisture content within the skin sample when moisture content and temperature dependency are introduced in the diffusivity. Such findings are important especially when developing skin multi-compartment physiologically based pharmacokinetic (PBPK) models to assess transdermal permeation of various hydrophilic penetrants. © 2008 The Institution of Chemical Engineers.
- Description: 2003006794
- «
- ‹
- 1
- ›
- »