Effects of emulsification of fat on the surface tension of protein solutions and surface properties of the resultant spray-dried particles
- Authors: Xu, Yun , Howes, Tony , Adhikari, Benu , Bhandari, Bhesh
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 16 (December 2013), p. 1939-1950
- Full Text: false
- Reviewed:
- Description: To examine the effect of protein adsorption on the fat-water interface on the surface composition of spray-dried particles, whey, hydrolyzed whey, and soy protein isolate emulsions were prepared at three different protein to fat ratios of 1:1, 1:5, and 1:10 and spray dried. Non-hydrolyzed whey protein isolate (WPI) and the more hydrolyzed whey protein solutions at 20.2% degree of hydrolysis (DH) had significantly lower surface tension values with fat than without fat. The correlation between the reduction of surface tension value of an emulsion and the increase in protein surface composition of powder particles was observed for WPI and HWP406 but was not observed for the other protein isolate types. It was clear that the spray-dried emulsions had fat as the dominant component on the surface of the powder particles and that the amount of protein on the surface became severely depressed at higher fat addition levels. In terms of its powder morphology, the unique powder structures such as the indentations and folds usually found on the surface of protein containing powders were not evident because they were compromised by the presence of high surface fat. The powder with higher surface fat had more crumpled particle structures and dimpled surfaces.
- Description: C1
Investigation of relationship between surface tension of feed solution containing various proteins and surface composition and morphology of powder particles
- Authors: Xu, Yun , Howes, Tony , Adhikari, Benu , Bhandari, Bhesh
- Date: 2012
- Type: Text , Journal article
- Relation: Drying Technology Vol. 30, no. 14 (2012), p. 1548-1562
- Full Text: false
- Reviewed:
- Description: The surface tension of freshly created food protein powder isolates was measured in aqueous solutions as a function of concentration, hydrolysis, and temperature. The surface tension of the solutions was measured immediately to best predict their surface-active behavior in a spray-drying scenario, where instantaneous values are more relevant than equilibrium surface tension measurements. Whole whey protein, hydrolyzed whey proteins (degrees of hydrolysis of 4, 9.5, 12, 17, and 20.2%), soy protein, pea protein isolates, and gelatin powders were diluted in a range of concentrations (0.04-2 g/L) and their surface tension values were reported at 23 +/- 1 degrees C. It was found that at higher concentrations hydrolyzed whey proteins at degrees of hydrolysis of 9.5 and 12%, and soy protein isolates in particular, showed excellent surface activity (shown through a decrease in surface tension) compared to nonhydrolyzed whey protein and gelatin. When comparing the influence of the degree of hydrolysis of whey proteins, the reverse was observed at lower concentrations (0.04-0.1 g/L), with the nonhydrolyzed whey protein reducing surface tension values more effectively than their hydrolyzed counterparts. Additionally, the protein solutions (2 g/L) were maintained at higher temperatures of 40, 50, and 60 degrees C and the surface tension values were measured. There was a general improvement of surface activity of proteins indicated by the reduced surface tension of solutions at these temperatures compared with the pure water values. The protein solutions were also spray dried with maltodextrin (MD30) and the powder particle surface composition and structures were analyzed via X-ray photoelectron spectroscopy and scanning electron micrography. There was a trend of correlation between the surface activities of protein in solution with that of the surface composition of protein found on the powder particles. However, there were morphological indicators that corresponded well to the amount of protein present on the surface.
Effect of addition of proteins on the production of amorphous sucrose powder through spray drying
- 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
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- 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.
Glass-transition based approach in drying of foods
- Authors: Bhandari, Bhesh , Adhikari, Benu
- Date: 2009
- Type: Book chapter
- Relation: Advances in Food Dehydration Chapter p. 37-62
- Full Text: false
- Description: 2003006836
Sticky and collapse temperature : Measurements, data and predictions
- Authors: Adhikari, Benu , Bhandari, Bhesh
- Date: 2009
- Type: Text , Book chapter
- Relation: Food properties handbook Chapter 11 p. 347-380
- Full Text: false
- Description: 2003007516
The effect of low molecular weight surfactants and proteins on surface stickiness of sucrose during powder formation through spray drying
- 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
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- 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.
Spray drying of skim milk mixed with milk permeate : Effect on drying behavior, physicochemical properties, and storage stability of powder
- Authors: Shrestha, A. , Howes, Tony , Adhikari, Benu , Bhandari, Bhesh
- Date: 2008
- Type: Text , Journal article
- Relation: Drying Technology Vol. 26, no. 2 (2008), p. 239-247
- Full Text: false
- Reviewed:
- Description: The possibility of using milk permeate (MP) to lower the protein level of skim milk powder (SMP) in producing powders of 34% and lower protein is explored. Skim milk suspensions with various levels of MP were prepared by mixing SMP and MP powder (MPP) at the ratios of 1: 0, 7: 3, 3: 7, and 0: 1: from 34 to 5.3% protein. The suspensions were dried in a spray dryer with inlet and outlet temperatures of 180 and 80 degrees C, respectively. Increasing permeate concentration in the mixture showed a greater tendency to stickiness manifested by lowered the cyclone recovery of the powder as more powder stuck on the wall of the dryer. Increasing permeate concentration in the resultant powder did not significantly affect the bulk density but led to a reduction in the particle size and also made the powder slight green and yellowish in color. It also found to lower the glass transition temperature (T-g) of the skim milk powder (SMP) and induce crystallization of lactose at lower water activity (a(w) >= 0.328 for SMP: MPP of 3: 7 and 0: 1 compared to a(w) >= 0.0.432 for SMP: MPP of 1: 0 and 3: 7). Addition of MP in SMP lowered the Tg values of the resulting powders. The permeate fraction in spray-dried SMP/MPP mixtures found to lower the critical aw and moisture content, suggesting the SMP mixed with MPP is more likely to become sticky than SMP alone (at 34% protein) when stored at a similar water activity and moisture content.
Water activity in food processing and preservation
- Authors: Bhandari, Bhesh , Adhikari, Benu
- Date: 2008
- Type: Text , Book chapter
- Relation: Drying Technologies in Food Processing Chapter p. 55-89
- Full Text: false
- Description: 2003006839
Glass transition behavior of spray dried orange juice powder measured by differential scanning calorimetry (DSC) and thermal mechanical compression test (TMCT)
- Authors: Shrestha, A. , Ua-Arak, T. , Adhikari, Benu , Howes, Tony , Bhandari, Bhesh
- Date: 2007
- Type: Text , Journal article
- Relation: International Journal of Food Properties Vol. 10, no. 3 (2007), p. 661-673
- Full Text: false
- Description: Spray drying behavior of orange juice concentrate with various levels of maltodextrin (DE 6) was studied. Five combinations of orange juice concentrate and maltodextrin (25:75, 30:70, 35:65, 40:60, and 50:50) were spray dried at 160 and 65 degrees C inlet and outlet temperatures, respectively. The product recovered with 50% maltodextrin concentration was sticky and only 20% powder was recovered. The recovery of orange juice powder increased as the amount of maltodextrin in powders increased. The particle size and bulk density remained almost the same in all except in 50% maltodextrin powder which was slightly larger and more dense. The moisture content of spray dried powders was high and desiccated before measuring glass transition temperature. The anhydrous spray dried powders showed increased T-g values with increasing maltodextrin concentration, from 66 degrees C in 50% maltodextrin to 97 degrees C in 75% maltodextrin containing powders. The glass rubber transition ( Tg-r) values of all the products measured using novel Thermal Mechanical Compression Test (TMCT) were higher than T-g values measured by DSC; the difference in values increased with increase in maltodextrin concentration.
Sticky behavior of whey protein isolate and lactose droplets during convective drying
- Authors: Adhikari, Benu , Howes, Tony , Shrestha, A. , Bhandari, Bhesh
- Date: 2006
- Type: Conference paper
- Relation: Paper presented at 2006 AIChE Spring National Meeting - 5th World Congress on Particle Technology, Orlando, Florida :
- Full Text: false
- Description: Stickiness of whey protein isolate (WPI) and spray dried lactose droplets was studied at two air temperatures (65±0.5°C, 80±0.5°C), 0.75 m/s air velocity and 2-2.5% relative humidity using an in situ stickiness testing device. A stainless steel probe with 50 mm/min contact/withdrawal speed was used. The moisture and temperature histories were measured through parallel experiments. In each case, the surface of the lactose droplet remained sticky and failed cohesively until the surface was completely surrounded with crystals. The crystal layer remained fragile, fractured upon the probe contact and a thin layer of solution came out to the probe surface even after the moisture (u, dry basis) was lower than 0.2. WPI droplets formed thin and smooth skin immediately after coming in contact with hot air. The tensile strength of this skin increased rapidly and peaked (u = 2.14 at 45°C and u = 1. 47 at 65.7°C) fairly early during drying process. WPI droplet surface became completely non-sticky soon after attaining the peak tensile strength (u =1.32 at 53.4 °C and u= 1.05 at 68.8°C), mainly due to transformation of the outer layer of the skin into glassy material. The skin forming and surface active nature of WPI was exploited to minimize the stickiness of honey during spray drying. Replacement of 5% (w/w) maltodextrin with WPI raised the powder recovery of honey solids from 28% to 80%. Stickiness of the WPI on glass, Teflon and polyurethane surfaces was studied by replacing the contact surface of the probe with these materials. It was found that the stickiness of glass surface was the highest at test temperatures. Teflon surface offered the lowest stickiness at the test temperatures making it suitable materials to minimize solution/particle stickiness through coating.
Thin-layer isothermal drying of fructose, maltodextrin, and their mixture solutions
- Authors: Adhikari, Benu , Howes, Tony , Shrestha, A. , Tsai, W. , Bhandari, Bhesh
- Date: 2006
- Type: Text , Journal article
- Relation: Drying Technology Vol. 24, no. 11 (2006), p. 1415-1424
- Full Text: false
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- Description: Solutions of fructose, maltodextrin (DE 5), and their mixtures at the ratios of 20:80, 40:60, 50:50, 60:40, and 80:20 were gelled with 1% agar-agar and dried under convective-conductive drying conditions. The thin slabs were maintained at isothermal drying condition of 30 and 50 degrees C. Yamamoto's simplified method based on regular regime approach was used to calculate the (effective) moisture diffusivity. Both the drying rates and the moisture diffusivity exhibited strong concentration dependence. The concentration dependence was stronger in the case of fructose and fructose rich solutions. Both the moisture diffusivity and drying rates of the mixture solutions were enhanced due to plasticization of fructose on maltodextrin, which is explained through free volume theory.
Glass transition behaviour of fructose
- Authors: Truong, V. , Bhandari, Bhesh , Howes, Tony , Adhikari, Benu
- Date: 2004
- Type: Text , Journal article
- Relation: International Journal of Food Science and Technology Vol. 39, no. 5 (2004), p. 569-578
- Full Text: false
- Reviewed:
- Description: The glass transition temperature and the second transition (the endothermic change between the glass transition and melting temperatures) of fructose were studied. The thermal history strongly affected both transitions of fructose. Storage for 10 days at 22degreesC increased the dynamic glass transition temperature from 16 to 25degreesC and decreased the second transition of fructose from 110 to 98degreesC in the first differential scanning calorimetric (DSC) scan. The amplitude of the second transition increased slightly with storage time and reached 260% of the first transition for vacuum oven dried samples. The effect of thermal history on the glass transition temperature of fructose can be removed by scanning the sample in a DSC to 130degreesC. The effects of water content, glucose and sucrose on the two transitions were also investigated.
Characterization of the surface stickiness of fructose-maltodextrin solutions during drying
- Authors: Adhikari, Benu , Howes, Tony , Bhandari, Bhesh , Truong, V.
- Date: 2003
- Type: Text , Journal article
- Relation: Drying Technology Vol. 21, no. 1 (2003), p. 17-34
- Full Text: false
- Reviewed:
- Description: A probe tack test has been used for the in situ characterization of the surface stickiness of hemispherical drops with an initial radius of 3.5 mm while drying. Surface stickiness of drops of fructose and maltodextrin solutions dried at 63degreesC and 95degreesC was determined. The effect of addition of maltodextrin on fructose solution-was studied with fructose/maltodextrin solid mass ratios of 4: 1, 1: 1, and 1:4. Pure fructose solutions remained completely sticky and failed cohesively even when their moisture approached zero. Shortly after the start of drying, the surface of the maltodextrin drops formed a skin, which rapidly grew in thickness. Subsequently the drop surface became completely nonsticky probably due to transformation of outer layers into a glassy material. Addition of malto,dextrin significantly altered the surface stickiness of drops of fructose solutions, demonstrating its use as an effective drying aid.
In situ characterization of stickiness of sugar-rich foods using a linear actuator driven stickiness testing device
- Authors: Adhikari, Benu , Howes, Tony , Bhandari, Bhesh , Truong, V.
- Date: 2003
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 58, no. 1 (2003), p. 11-22
- Full Text: false
- Reviewed:
- Description: A stickiness testing device based on the probe tack test has been designed and tested. It was used to perform in situ characterization of drying hemispherical drops with an initial radius 3.5 mm. Tests were carried out in two drying temperatures, 63 and 95 degreesC. Moisture and temperature histories of the drying drops of fructose, honey, sucrose, maltodextrin and sucrose-maltodextrin mixtures were determined. The rates of moisture evaporation of the fructose solution was the fastest while those of the maltodextrin solution was the lowest. A profile reversal was observed when the temperature profiles of these materials were compared. Different modes of failure were observed during the stickiness tests. Pure fructose and honey solutions remained completely sticky and failed cohesively until the end of drying. Pure sucrose solution remained sticky and failed cohesively until complete crystallization occurred. The surface of the maltodextrin drops formed a skin shortly after the start of drying. It exhibited adhesive failure and reached a state of non-adhesion. Addition of maltodextrin significantly altered the stickiness of sucrose solution. (C) 2002 Elsevier Science Ltd. All rights reserved.
Surface stickiness of drops of carbohydrate and organic acid solutions during convective drying : Experiments and modeling
- Authors: Adhikari, Benu , Howes, Tony , Bhandari, Bhesh , Troung, V.
- Date: 2003
- Type: Text , Journal article
- Relation: Drying Technology Vol. 21, no. 5 (2003), p. 839-873
- Full Text: false
- Reviewed:
- Description: Drying kinetics of low molecular weight sugars such as fructose, glucose, sucrose and organic acid such as citric acid and high molecular weight carbohydrate such as maltodextrin (DE 6) were determined experimentally using single drop drying experiments as well as predicted numerically by solving the mass and heat transfer equations. The predicted moisture and temperature histories agreed with the experimental ones within 6% average relative (absolute) error and average difference of +/- 1degreesC, respectively. The stickiness histories of these drops were determined experimentally and predicted numerically based on the glass transition temperature (T-g) of surface layer. The model predicted the experimental observations with good accuracy. A nonsticky regime for these materials during spray drying is proposed by simulating a drop, initially 120 mum in diameter, in a spray drying environment.