Showing items 1 - 9 of 9

Comparative study of film forming behaviour of low and high amylose starches using glycerol and xylitol as plasticizers

- Muscat, Delina, Adhikari, Benu, Adhikari, Raju, Chaudhary, Deeptangshu

  • Authors: Muscat, Delina , Adhikari, Benu , Adhikari, Raju , Chaudhary, Deeptangshu
  • Date: 2011
  • Type: Text , Journal article
  • Relation: Journal of Food Engineering Vol.109, no.2 (2011), p.189-201
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  • Description: In this study, the film forming behaviour of low amylose (LA) and high amylose (HA) starches was studied. The starch-alone and a blend of plasticizer (polyol)-starch films were developed by gelatinising at various temperatures and casting at 25 °C. The starch-plasticizer films contained glycerol and xylitol either individually or in 1:1 combination. The concentration of plasticizer used was 15%, 20% and 30% for LA films while it was 20%, 30% and 40% for HA films on dry solid basis. The HA-glycerol films retained the highest moisture content among all the films. The HA films exhibited higher glass transition temperature, higher tensile strength, higher modulus of elasticity and lower elongation at break than those obtained from LA starch. The tensile strength and modulus of elasticity decreased and the elongation increased with increasing plasticizer concentrations above 15% on dry solid basis regardless the starch type. Low water vapour permeability was evident in LA and HA films plasticized by combined plasticizers at 20% plasticizer concentration. Rheological measurements showed that most of the suspensions exhibited Herschel-Bulkley behaviour and some of the HA suspensions exhibited Bingham plastic behaviour. At 15% (on dry solid basis) plasticizer concentration, the films obtained from both the starches were brittle due to the anti-plasticization behaviour. © 2011 Elsevier Ltd. All rights reserved.

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
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  • 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.

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.
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  • Description: •Synchrotron-FTIR showed the distribution of wax and PEG-isocyanate across the film.•Wax and PEG-isocyanate distributions and film surface altered the film's hydrophobicity.•High contact angle occurred when PEG-isocyanate was concentrated in the middle of the film.•Hydrophobic films possessed hierarchical wax pinnacles and textured surface.•The wax pinnacles were 10μm in diameter and distributed very closely to each other. 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.

Physicochemical and functional characteristics of lentil starch

- Joshi, Matina, Aldred, Peter, McKnight, Stafford, Panozzo, Joe, Kasapis, Stefan, Adhikari, Raju, Adhikari, Benu

  • Authors: Joshi, Matina , Aldred, Peter , McKnight, Stafford , Panozzo, Joe , Kasapis, Stefan , Adhikari, Raju , Adhikari, Benu
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Carbohydrate Polymers Vol. 92, no. 2 (2013), p. 1484-1496
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  • Description: The physicochemical properties of lentil starch were measured and linked up with its functional properties and compared with those of corn and potato starches. The amylose content of lentil starch was the highest among these starches. The crystallinity and gelatinization enthalpy of lentil starch were the lowest among these starches. The high amylose: amylopectin ratio in lentil starch resulted into low crystallinity and gelatinization enthalpy. Gelatinization and pasting temperatures of lentil starch were in between those of corn and potato starches. Lentil starch gels showed the highest storage modulus, gel strength and pasting viscosity than corn and potato starch gels. Peleg's model was able to predict the stress relaxation data of these starches well (R2 > 0.98). The elastic modulus of lentil starch gel was less frequency dependent and higher in magnitude at high temperature (60 °C) than at lower temperature (10 °C). Lentil starch is suitable where higher gel strengthened pasting viscosity are desired. © 2012 Elsevier Ltd.
  • Description: 2003011035

Preparation and characterization of glycerol plasticized (high-amylose) starch-chitosan films

- Liu, Huihua, Adhikari, Raju, Guo, Qipeng, Adhikari, Benu

  • Authors: Liu, Huihua , Adhikari, Raju , Guo, Qipeng , Adhikari, Benu
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Journal of Food Engineering Vol. 116, no. 2 (2013), p. 588-597
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  • Description: The chitosan-starch (high amylose) blend film (1;1), via microfluidization, was prepared by casting with different glycerol concentration (0%, 2.5%, 5% and 10%). The films were characterized for their mechanical, thermal and morphological properties. The addition of glycerol at 5% (w/w) and higher concentrations resulted in decrease in tensile strength, increase in elongation at break due to plasticization. The wellknown antiplasticization was observed in the polymer films with 2.5% of glycerol. The addition of glycerol promoted the interactions among chitosan, starch and glycerol through hydrogen bonding as reflected on the shifting of main peaks of the glycerol-free film to higher wavenumbers as shown by FTIR spectra. The decrease in intensity of glycerol-related peaks in starch-chitosan-glycerol films in both 1H NMR and 13C NMR spectra proved the strong interactions (decrease in glycerol mobility) occurring among starch, chitosan and glycerol in glycerol-plasticized films. © 2012 Elsevier Ltd. All rights reserved.
  • Description: C1

The effect of food-grade low-molecular-weight surfactants and sodium caseinate 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 Biophysics Vol. 5, no. 2 (2010), p. 128-137
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  • Description: The effect of low-molecular-weight surfactants (LMS) and sodium caseinate (NaCas) on spray drying of sugar-rich foods has been studied. Sucrose and NaCas were selected as a model sugar-rich food and protein, respectively. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween 80) were chosen as model ionic and nonionic LMS. Sucrose-NaCas solutions with the solids ratio of 99.5:0.5 in the absence and presence (0.01% and 0.05%) of SSL and Tween 80 were prepared. The feed solutions had 25% solid concentration in all cases. The dynamic surface tension (DST) values of the solutions were measured for 100 s and the solutions were subsequently spray dried at inlet and outlet temperatures of 165 and 65 °C, respectively. The glass-rubber temperature (Tg-r), the surface elemental composition and amorphous-crystalline nature of the powders were also determined. At these concentrations and experimental time frame, it was found that the proteins preferentially migrated to the air-water interface reasonably swiftly. The addition of LMS resulted in partial or complete displacement of the proteins from the air-water interface. For spray-drying trials with the yield of 82.0%, it was found that 52.0% of the powder particle surface was covered with proteins. The powder recovery was greatly reduced by the LMS concentration and type. At 0.05% on dry solid basis, in the case of nonionic surfactant (Tween 80), the displacement of protein from the surface was such that no powder was recovered. The ionic surfactant (SSL) displaced 2.0% and 29.3% proteins from the droplet surface at concentrations of 0.01% and 0.05%, respectively, resulting in 75.5 ± 1.8% and 30.1 ± 1.4% powder yield. The Tg-r results revealed that the amount of protein required for successful spray drying of the sucrose-protein solution depends on the amount of proteins present in the droplet surface but not in the bulk. X-ray diffraction and scanning electron microscopy results confirmed that the powders of both sucrose-NaCas and sucrose-NaCas with 0.01% SSL were mostly amorphous, while those with sucrose-NaCas-Tween 80 (0.01%) and sucrose-NaCas-SSL (0.05%) were crystalline. © 2010 Springer Science+Business Media, LLC.

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
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  • 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 effects of proteins and low molecular weight surfactants on spray drying of model sugar-rich foods: Powder production and characterisation

- Jayasundera, Mithila, Adhikari, Benu, Adhikari, Raju, Aldred, Peter

  • Authors: Jayasundera, Mithila , Adhikari, Benu , Adhikari, Raju , Aldred, Peter
  • Date: 2011
  • Type: Text , Journal article
  • Relation: Journal of Food Engineering Vol. 104, no. 2 (2011), p. 259-271
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  • Description: The effects of proteins and low molecular weight surfactants (LMS) on spray drying and powder characteristics of model sugar-rich foods have been studied. Fructose and sucrose were selected as model sugar-rich foods and sodium caseinate (NaCas) was selected as a model protein. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween-80) were chosen as model ionic and non-ionic low molecular weight surfactants. The feed solutions for spray drying had 25% solid concentration in all. To achieve identical powder recoveries of the order of 80% much higher NaCas:fructose ratio (30:70) was required compared to NaCas:sucrose ratio (0.5:99.5) which corresponded to 7.89% and 0.13% of sodium caseinate (initial bulk concentration), respectively. There was no change in powder recovery when the SSL concentration was increased from 0.01% to 0.05% in fructose-NaCas-SSL solution and also addition of 0.01% Tween-80 into fructose-NaCas solution did not affect the powder recovery (76.7 ± 2.3%), however, it was slightly affected with the increase of Tween-80 to 0.05% (69.0 ± 1.9%). At NaCas concentration above critical micelle concentration of NaCas (3% w/w), the presence of up to 0.05% low molecular weight surfactants had either no effect or minimal effect on the surface coverage of the droplets/particles and also on the powder recovery depending on the nature of the low molecular weight surfactants. The surface protein coverage and the recovery of the powder in sucrose-protein systems were very sensitive in the presence of low molecular weight surfactants due to being below the critical micelle concentration of NaCas. SSL displaced 2.0% and 29.3% of proteins from the droplet surface of sucrose-NaCas-SSL, respectively, when its concentration was varied from 0.01% to 0.05% thereby reducing the powder recovery from 75.5% to 30%. 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 of NaCas from the droplet surface and no powder was recovered. These phenomena are explained on the basis of surface-glass transition temperature, dynamic surface tension, nature of surfactants and glass transition temperature of sugars used. X-ray diffraction and scanning electron microscopy results showed that the powders of sucrose-NaCas, sucrose-NaCas with 0.01% SSL and all powders of fructose were amorphous. © 2010 Elsevier Ltd. All rights reserved.

The physicochemical characteristics and hydrophobicity of high amylose starch-glycerol films in the presence of three natural waxes

- Muscat, Delina, Adhikari, Raju, McKnight, Stafford, Guo, Qipeng, Adhikari, Benu

  • Authors: Muscat, Delina , Adhikari, Raju , McKnight, Stafford , Guo, Qipeng , Adhikari, Benu
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Journal of Food Engineering Vol. 119, no. 2 (2013), p. 205-219
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  • Description: The film forming behaviour and hydrophobicity of high amylose (HA) starch in the presence of three different natural waxes (beeswax, candelilla wax and carnauba wax) were studied in the presence and absence of Tween-80. The HA starch:glycerol (G) ratio was maintained at 80:20 (on dry solid basis) and the concentration of wax was varied from 5% and 10% (w/w). The melted wax samples were homogenized with HAG dispersion with or without Tween-80 and the films were prepared by solution casting. The hydrophobicity and water-barrier properties in these films were determined by using contact angle (CA), water vapour permeability (K
  • Description: 2003011133
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