Fruits and vegetable powders
- Authors: Jiang, Hao , Zhang, Min , Adhikari, Benu
- Date: 2023
- Type: Text , Book chapter
- Relation: Handbook of Food Powders: Chemistry and Technology, Second Edition Chapter 24 p. 423-436
- Full Text: false
- Reviewed:
- Description: Fruits and vegetables are rich in vitamins, carotenoids, ascorbic acid, minerals and dietary fibre; however, they are climacteric and their shelf-life is very short after harvest. Uncontrolled browning, wilting and loss of nutritional value are typical of fresh fruits and vegetables even at ambient temperature and relative humidity (RH). When converted into powder form, they are easy to preserve, transport, store and use as ingredients. The greatly reduced water content and water activity help prolong the shelf-life of fruit and vegetable powders. The loss of important nutrients can also be minimized during the powder production process by judiciously selecting the drying methods and encapsulating shell materials. © 2024 Elsevier Ltd. All rights reserved.
Drying and denaturation characteristics of α-LACTALBUMIN, β-lactoglobulin, and bovine serum albumin in a convective drying process
- Authors: Haque, M. Amdadul , Aldred, Peter , Chen, Jie , Barrow, Colin , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Agricultural and Food Chemistry Vol. 62, no. 20 (2014), p. 4695-4706
- Full Text: false
- Reviewed:
- Description: Drying and denaturation kinetics of aqueous droplets of α-lactalbumin (α-lac), β-lactoglobulin (β-lg), and bovine serum albumin (BSA) were measured in a convective drying environment. Single droplets having an initial droplet diameter of 2 ± 0.1 mm and containing 10% (w/v) protein concentration were dried using conditioned air (65 and 80 °C, 2-3% RH, 0.5 m/s velocity) for 600 s. The denaturation of these proteins was measured by using reversed-phase HPLC. At the end of 600 s of drying 13.3 and 19.4% α-lac was found to be lost due to denaturation at 65 and 80 °C, respectively. Up to 31.0% of β-lg was found to be denatured, whereas BSA was not found to be significantly (p > 0.05) denatured in these drying conditions. The formation and strength of skin and the associated morphological features were found to be linked with the degree of denaturation of these proteins. The secondary structure of these proteins was significantly (p < 0.05) affected and altered by the drying stresses. The β-sheet and random coil contents were increased in α-lac by 6.5 and 4.0%, respectively, whereas the α-helix and β-turn contents decreased by 5.5 and 5.0%, respectively. The β-sheet and random coil contents in β-lg were increased by 7.5 and 2.0%, respectively, whereas the α-helix and β-turn contents decreased by 3.5 and 6.0%, respectively. In the case of BSA the β-sheet, α-helix, and random coil contents were found to increase, whereas the β-turn content decreased. © 2014 American Chemical Society.
Guest Editorial: Special Thematic Issue on Drying of Proteins and Enzymes
- Authors: Adhikari, Benu , Devahastin, Sakamon , Mujumdar, Arun
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 13-14 (2013), p. 1439-1440
- Full Text: false
- Reviewed:
- Description: The idea of publishing a special issue on proteins and enzymes was conceived during the 18th International Drying Symposium (IDS2012) held in the historical city of Xiamen, China (November 11-15, 2012). It appeared to us that a number of scientists and engineers were enthusiastically undertaking research in various aspects of drying of proteins and enzymes. Professors Arun Mujumdar and Sakamon Devhastin encouraged me to explore the possibility of bringing at least one special issue that would depict contemporary research undertakings in the broader theme involving proteins and enzymes. We were somewhat unsure in the beginning whether or not the required number of high quality mansucripts could be garnered for one issue in the time constraint we had in mind. Editorial
- Description: C3
The adsorption and release characteristics of CPFX in porous starch produced through different drying methods
- Authors: Gao, Fei , Li, Dong , Bi, Chonghao , Mao, Zhihuai , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 13-14 (2013), p. 1592-1599
- Full Text: false
- Reviewed:
- Description: The drug adsorption and release characteristics of porous starches produced through hot air drying, spray drying, and vacuum freeze drying were investigated using ciprofloxacin as model drug. A UV/visible spectrophotometer, Fourier-transform infrared spectrometer, differential scanning calorimeter, and X-ray diffractometer were used to determine the drug adsorption/release, drug/starch interaction, glass transition, and crystallinity of porous starch samples. The amount of ciprofloxacin adsorbed in three different porous starches was 5.58%, 8.91%, and 11.43%, respectively. The ciprofloxacin-loaded porous starches had glass-transition-related endothermic peaks between 55°C and 65°C and melting-related endothermic peaks between 120°C and 150°C. Up to 75% of the loaded ciprofloxacin was released from the freeze-dried sample within 30 hrs. The freeze-dried porous starch also showed higher ciprofloxacin loading rate, higher glass transition temperature, and higher ciprofloxacin release rate. A two-phase dynamic drug release model was found to satisfactorily fit the release kinetics of ciprofloxacin (R2 > 0.995). © 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
- 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
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- 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.
Physicochemical and functional properties of lentil protein isolates prepared by different drying methods
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan
- Date: 2011
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 129, no. 4 (2011), p. 1513-1522
- Full Text: false
- Reviewed:
- Description: Lentil protein isolate (LPI) extract was converted into powder by freeze drying, spray drying and vacuum drying. Differences in particle size distribution, protein subunit composition and colour and surface morphology were observed amongst the three drying methods. Spray and freeze-dried LPI powders exhibited higher solubility (81% and 78%, respectively) compared to vacuum dried powders (50%). The spray dried powders showed a low water absorption capacity (0.43 ± 0.02 g/g) compared to freeze (0.48 ± 0.02 g/g) and vacuum-dried (0.47 ± 0.01 g/g) LPI powders. Spray and freeze-dried powders displayed better gelation ability and higher gel strength, compared to vacuum-dried powder. Both spray and freeze-dried gels showed typical viscoelastic gel characteristics, with G′ dominating over G″ and very low loss tangent. The holding time required for gelation of vacuum dried powder at 90 °C was significantly longer, compared to spray and freeze dried powders. Hence, drying methods used for preparation of lentil protein isolate powders can affect physicochemical and associated functional properties. © 2011 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.
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
- 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:
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- 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