The effect of food-grade low-molecular-weight surfactants and sodium caseinate on spray drying of sugar-rich foods
- 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
- Full Text: false
- 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.
Surface modification of spray dried food and emulsion powders with surface-active proteins : A review
- 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 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.
The effects of proteins and low molecular weight surfactants on spray drying of model sugar-rich foods: Powder production and characterisation
- 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
- Full Text: false
- Reviewed:
- 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.
Surface protein coverage and its implications on spray-drying of model sugar-rich foods: Solubility, powder production and characterisation
- Authors: Jayasundera, Mithila , Adhikari, Benu , Howes, Tony , Aldred, Peter
- Date: 2011
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 128, no. 4 (2011), p. 1003-1016
- Full Text: false
- Reviewed:
- Description: We have investigated the amount of protein required to produce amorphous sugar powders through spray-drying. Pea protein isolate was used as a model plant protein and sodium caseinate was used as a model dairy protein. Powder recovery in a laboratory spray dryer was used as a measure of the ease of spray drying for a given formulation. More than 80% of amorphous sucrose and fructose was produced with the addition of sodium caseinate, while the pea protein isolate was able to produce only recoveries of less than 50% of amorphous sucrose. Sensitivity of low molecular weight surfactants has been demonstrated using both ionic (sodium stearoyl lactylate) and non-ionic (polysorbate-80) surfactants. Spray-dried powders were subjected to physico-chemical characterisation and dissolution experiments. The maximum solubility of all powders was obtained after 5 min of dissolution. The solubility of the sodium caseinate increased by 6-7% in the presence of fructose and low molecular weight surfactants. The solubility of the amorphous powders of sucrose-pea protein isolate was found to be lower than amorphous powders of sucrose-sodium caseinate and fructose-sodium caseinate. The addition of sucrose in water increased the solubility of the pea protein isolate from 16.84% to more than 83%. The non-ionic surfactant (Tween-80) has reduced the solubility of sucrose-pea protein isolate-Tween-80 powders significantly (p < 0.05) compared to those of sucrose-pea protein isolate-sodium stearoyl lactylate powders. The solubility of sucrose-sodium caseinate powders was comparable to that of pure sodium caseinate, indicating that addition of sucrose into 0.13% sodium caseinate does not have any significant effect on the solubility of this protein at this concentration. © 2011 Elsevier Ltd. All rights reserved.