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.
Recent advances in the microencapsulation of omega-3 oil and probiotic bacteria through complex coacervation : A review
- Authors: Eratte, Divya , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Trends in Food Science and Technology Vol. 71, no. (2018), p. 121-131
- Full Text: false
- Reviewed:
- Description: Background Functional foods are a fastest growing sector of the food industry. The development of functional foods comprising omega-3 fatty acids and probiotic bacteria, through complex coacervation process is an emerging area of research and product development. Scope and approach We reviewed relevant literature concerning the use of complex coacervation in microencapsulation, focusing primarily on the inclusion of probiotic bacteria and omega-3 oils into a single delivery format. This review covers advantages and disadvantages of the complex coacervation process to microencapsulate bioactive ingredients, viability of probiotic bacteria and oxidative stability of omega-3 oil during the complex coacervation process, the bioaccessibility of omega-3 oil and probiotic bacteria during simulated gastrointestinal conditions and in-vivo testings. Key findings and conclusions The review describes the advantages of co-encapsulation using complex coacervation followed by spray drying. It also describes the technological hurdles that need to be resolved for further development of industrial applications of co-encapsulation of probiotic bacteria and omega-3 lipids. The co-encapsulation concept has been widely used in pharmaceutical delivery systems, but is a relatively new concept in food ingredient stabilisation and delivery. There is a commercial need of co-encapsulation of multiple bioactive ingredients within a single microcapsules, due to decreased cost and enhanced product quality. Complex coacervation has been shown to be a useful method for the co-encapsulation of multiple unstable bioactive ingredients. Although in-vitro evaluation deliver useful bioavailability information, additional in-vivo and clinical trials are needed to determine the efficacy of bioactive release, particularly for microcapsules containing multiple bioactive ingredients. © 2017 Elsevier Ltd
In-vitro digestion of probiotic bacteria and omega-3 oil co-microencapsulated in whey protein isolate-gum Arabic complex coacervates
- Authors: Eratte, Divya , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2017
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 227, no. (2017), p. 129-136
- Full Text: false
- Reviewed:
- Description: Solid co-microcapsules of omega-3 rich tuna oil and probiotic bacteria L. casei were produced using whey protein isolate-gum Arabic complex coacervate as wall material. The in-vitro digestibility of the co-microcapsules and microcapsules was studied in terms of survival of L. casei and release of oil in sequential exposure to simulated salivary, gastric and intestinal fluids. Co-microencapsulation significantly increased the survival and surface hydrophobicity and the ability of L. casei to adhere to the intestinal wall. No significant difference in the assimilative reduction of cholesterol was observed between the microencapsulated and co-microencapsulated L. casei. The pattern of release of oil from the microcapsules and co-microcapsules was similar. However, the content of total chemically intact omega-3 fatty acids was higher in the oil released from co-microcapsules than the oil released from microcapsules. The co-microencapsulation can deliver bacterial cells and omega-3 oil to human intestinal system with less impact on functional properties. © 2017 Elsevier Ltd
Effect of moisture content and heating rates on the thermal properties of rice embryos measured by differential scanning calorimetry
- Authors: Yan, Ping-yu , Wang, Li-jun , Li, Dong , Adhikari, Benu , Mao, Zhihuai
- Date: 2016
- Type: Text , Journal article
- Relation: International Agricultural Engineering Journal Vol. 25, no. 1 (2016), p. 38-42
- Full Text: false
- Reviewed:
- Description: The effect of moisture content on the thermal properties of rice embryos was investigated using differential scanning calorimetry (DSC). A long grain hybrid rice variety (Jinyou 974) grown in Hunan Province of China was selected in this investigation. The temperature scanning tests were carried out from 20°C to 180°C at different heating rates from 2°C/min to 20°C/min. Consistently higher values of glass transition temperature (Tg) were measured when higher heating rates were used during DSC measurements at every set of moisture contents. The Tg values decreased from (65.28±0.38)°C to (31.08±0.26)°C with increase in moisture content from (10.7±0.3)% to (22.0±0.7)% (w/w). The analysis of variance and the regression analysis showed that both the linear function and Gordon Taylor model can adequately represent the variation of Tg with moisture content (R2 > 0.96).
Microencapsulation of flaxseed oil in flaxseed protein and flaxseed gum complex coacervates
- Authors: Kaushik, Pratibha , Dowling, Kim , McKnight, Stafford , Barrow, Colin , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Food Research International Vol. 86, no. (2016), p. 1-8
- Full Text: false
- Reviewed:
- Description: Flaxseed oil, a rich source of omega-3 fatty acids, was microencapsulated in a novel matrix formed by complex coacervation between flaxseed protein isolate (FPI) and flaxseed gum (FG). This matrix was crosslinking with glutaraldehyde. Liquid microcapsules with three core (oil)-to-wall ratios (1:2, 1:3 and 1:4) were prepared and spray-dried or freeze-dried to produce powders. The microencapsulation efficiency, surface oil, morphology and oxidative stability of these microcapsules were determined. The spray-dried solid microcapsules had higher oil microencapsulation efficiency, lower surface oil content, smoother surface morphology and higher oxidation stability than the freeze-dried microcapsules. The highest microencapsulation efficiency obtained in spray-dried microcapsules was 87% with a surface oil of 2.78% at core-to-wall ratio 1:4 and oil load 20%. The oxidation stability obtained from spray-dried microcapsules at core-to-wall ratio of 1:4 was nearly double that of the unencapsulated flaxseed oil. © 2016 Elsevier Ltd.
Preparation, characterization and functional properties of flax seed protein isolate
- Authors: Kaushik, Pratibha , Dowling, Kim , McKnight, Stafford , Barrow, Colin , Wang, Bo , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 197, no. (2016/04/15/ 2016), p. 212-220
- Full Text: false
- Reviewed:
- Description:
Flaxseed protein isolate (FPI) was extracted from flaxseeds, and its amino acid composition and functional properties (solubility, thermal stability, emulsifying properties and electrostatic charge density, water holding and fat absorption capacities) were determined. The highest purity of FPI (90.6%) was achieved by extraction at 60°C. FPI had a low lysine to arginine ratio of 0.25, which is desired in heart-healthy foods and infant formulas. The denaturation temperature of FPI was 105°C. FPI had the highest emulsion activity index (375.51m2/g), highest emulsion stability index (179.5h) and zeta potential (−67.4mV) when compared to those of other commonly used proteins, such as sodium caseinate (SC), whey protein isolate (WPI), gelatin (Gel) and soy protein isolate (SPI). The average emulsion droplet size of emulsions stabilized by these proteins was in the order SC
Survival and fermentation activity of probiotic bacteria and oxidative stability of omega-3 oil in co-microcapsules during storage
- Authors: Eratte, Divya , Wang, Bo , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of Functional Foods Vol. 23, no. (2016), p. 485-496
- Full Text: false
- Reviewed:
- Description: Tuna oil (O) and probiotic bacteria Lactobacillus casei (P) were co-microencapsulated in whey protein isolate (WPI)-gum Arabic (GA) complex coacervate. The co-microcapsules (WPI-P-O-GA), L. casei microcapsules (WPI-P-GA) and tuna oil microcapsules (WPI-O-GA) were converted into powder using spray and freeze drying. The interaction between probiotic bacteria and omega-3 oil in co-microcapsules, particularly in terms of oxidative stability of omega-3 oil and vitality/viability of probiotic bacteria and any synergistic outcome, was studied. The effect of storage temperature (5 and 25 °C) and time (90 days) on the survival and fermentation activity of L. casei and oxidative stability of tuna oil in the microcapsules/co-microcapsules was determined. A synergism between oxidative stability of omega-3 oil and vitality of probiotic bacteria was observed, when they were co-microencapsulated and spray dried. These co-microcapsules will likely have utility in functional food formulations due to simple and cost effective stabilisation and delivery of two important functional ingredients. © 2016 Elsevier Ltd.
Survival, oxidative stability, and surface characteristics of spray dried co-microcapsules containing omega-3 fatty acids and probiotic bacteria
- 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
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- 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.
Co-encapsulation and characterisation of omega-3 fatty acids and probiotic bacteria in whey protein isolate-gum Arabic complex coacervates
- Authors: Eratte, Divya , McKnight, Stafford , Gengenbach, Thomas , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Functional Foods Vol. 19, no. (2015), p. 882-892
- Full Text: false
- Reviewed:
- Description: Omega-3 fatty acids and probiotic bacteria were co-encapsulated in a single whey protein isolate (WPI)-gum Arabic (GA) complex coacervate microcapsule. Tuna oil (0) and Lactobacillus casei 431 (P) were used as models of omega-3 and probiotic bacteria, respectively. The co-microcapsules (WPI-P-O-GA) and L. casei containing microcapsules (WPI-P-GA) were converted into powder by using spray and freeze drying. The viability of L. casei was significantly higher in WPI-P-O-GA co-microcapsules than in WPI-P-GA. The oxidative stability of tuna oil was significantly higher in spray dried co-capsules than in freeze dried ones. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.
Complex coacervation between flaxseed protein isolate and flaxseed gum
- 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.
Denaturation and physical characteristics of spray-dried whey protein isolate powders produced in the presence and absence of Lactose, Trehalose, and Polysorbate-80
- Authors: Haque, M. Amdadul , Chen, Jie , Aldred, Peter , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Drying Technology Vol. 33, no. 10 (2015), p. 1243-1254
- Full Text: false
- Reviewed:
- Description: The denaturation (loss of protein through aggregation and/or change in secondary structure) and physical characteristics such as powder morphology, particle size and size distribution, amorphous/crystalline behavior, and solubility of whey protein isolate (WPI) were investigated in a spray-drying process. The protective efficacy of sugars (lactose and trehalose) and low-molecular-weight surfactant polysorbate-80 (Tween-80) on the secondary structure (-turn, -sheet and -helix) and physical characteristics of spray-dried WPI was quantified. The WPI, WPI+sugar, and WPI+Tween-80 formulations were spray dried maintaining the total solids at 10% (w/w). The inlet and outlet temperatures were maintained at 180 and 80 degrees C, respectively. The results showed that the loss of protein through denaturation and aggregation was not significant (p>0.05). However, a significant (p<0.05) alteration of the secondary structural elements was observed. Due to spray drying of WPI without protectants, the -sheet and -turn were decreased by 4.4 and 14.5%, respectively, and the random coil increased by 20.7%. The -helix of WPI remained unaltered during the spray-drying process. The presence of Tween-80 effectively protected the -helix and -sheet but the -turn remained vulnerable and was decreased. No significant (p>0.05) change in the solubility of WPI was observed due to spray drying. Spray drying of WPI+sugar produced essentially amorphous particles. The dried powder particles were spherical with wrinkled or folded surface.
Drying and denaturation characteristics of whey protein isolate in the presence of lactose and trehalose
- Authors: Haque, M. Amdadul , Chen, Jie , Aldred, Peter , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 177, no. (2015), p. 8-16
- Full Text: false
- Reviewed:
- Description: The denaturation kinetics of whey protein isolate (WPI), in the presence and absence of lactose and trehalose, was quantified in a convective air-drying environment. Single droplets of WPI, WPI-lactose and WPI-trehalose were dried in conditioned air (2.5% RH, 0.5 m/s air velocity) at two temperatures (65°C and 80°C) for 500 s. The initial solid concentration of these solutions was 10% (w/v) in all the samples. Approximately 68% of WPI was denatured when it was dried in the absence of sugars. Addition of 20% trehalose prevented the irreversible denaturation of WPI at both temperatures. Thirty percent lactose was required to prevent denaturation of WPI at 65°C and the same amount of lactose protected only 70% of WPI from denaturation at 80°C. The secondary structures of WPI were found to be altered by the drying-induced stresses, even in the presence of 20% trehalose and 30% lactose.
Kinetics of argy wormwood (Artemisia argyi) leaf peroxidase and chlorophyll content changes due to thermal and thermosonication treatment
- Authors: Xin, Ying , Zhang, Min , Yang, Hongshun , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Food Science and Technology-Mysore Vol. 52, no. 1 (2015), p. 249-257
- Full Text: false
- Reviewed:
- Description: The effects of different thermal and thermosonication blanching treatments on the inactivation of peroxidase (POD) and the retention of total chlorophyll in argy wormwood leaves were studied. Inactivation of POD followed a biphasic first-order model under thermal blanching treatments below 90 A degrees C while a first-order model at 90 A degrees C. In contrast, for thermosonication treatments, the inactivation kinetics of POD fit a first-order model well for all the temperatures tested. Thermosonication treatment was found to inactivate POD faster and retain more of the total chlorophyll than thermal blanching treatment. A thermosonication protocol using ultrasonic intensity of 11.94 W/cm(2) at 85 A degrees C for 60 s was found to be the most suitable protocol for blanching the argy wormwood leaves. This protocol inactivated 92. 7 % POD while retaining 96.7 % of total chlorophyll.
Microencapsulation of omega-3 fatty acids : A review of microencapsulation and characterization methods
- Authors: Kaushik, Pratibha , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article , Review
- Relation: Journal of Functional Foods Vol. 19, no. Part B (2015), p. 868-881
- Full Text: false
- Reviewed:
- Description: To improve consumption of omega-3 fatty acids, foods can be enriched with omega-3 rich oils. Microencapsulation of omega-3 oils minimizes oxidative deterioration and allows their use in stable and easy-to-handle form. Microencapsulation of omega-3 fatty acids can be achieved by using a variety of methods, with the two most commonly used commercial processes being complex coacervation and spray dried emulsions. A variety of other methods are in development including spray chilling, extrusion coating and liposome entrapment. The key parameter in any of these processes is the selection of wall material. For spray dried emulsions and complex coacervates protein or polysaccharides are primarily used as shell material, although complex coacervation is currently commercially limited to gelatin. Here we review the need for microencapsulation of omega-3 oils, methods of microencapsulation and analysis, and the selection of shell material components. In particular, we discuss the method of complex coacervation, including its benefits and limitations. This review highlights the need for research on the fundamentals of interfacial and complexation behaviour of various proteins, gums and polyphenols to encapsulate and deliver omega-3 fatty acids, particularly with regard to broadening the range of shell materials that can be used in complex coacervation of omega-3 rich oils. © 2014 Published by Elsevier Ltd. All rights reserved.
Research trends in selected blanching pretreatments and quick freezing technologies as applied in fruits and vegetables : A review
- Authors: Xin, Ying , Zhang, Min , Xu, Baoguo , Adhikari, Benu , Sun, Jincai
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Refrigeration Vol. 57, no. (2015), p. 11-25
- Full Text: false
- Reviewed:
- Description: Abstract This paper presents a comprehensive review of recent developments in thermal (radio frequency, microwave and ohmic), non-thermal (high pressure, ultrasound and infrared) methods in blanching pretreatment. Recent developments in quick freezing technology (high pressure, dehydrofreezing and ultrasound-assisted) as applied to freezing of fruits and vegetables are also reviewed. The thermal and non-thermal blanching methods provide rapid and uniform heating; reduce the loss of soluble nutrients and minimize thermal damage compared to conventional hot water blanching. High pressure freezing seems to promote instantaneous and homogeneous ice nucleation in fruits and vegetables. Dehydrofreezing is capable of reducing the damage to plant texture by removal partial of water before freezing. Ultrasound-assisted freezing is found to be effective in the initiation of nuclei and subsequent growth of crystals. More fundamental researches are needed for better design and scale up, so that these technologies can be transferred from laboratory to industry. © 2015 Elsevier Ltd and IIR.
Changes in Quality Characteristics of Fresh-cut Cucumbers as Affected by Pressurized Argon Treatment
- Authors: Meng, Xiangyong , Zhang, Min , Zhan, Zhonggang , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Food and Bioprocess Technology Vol. 7, no. 3 (2014), p. 693-701
- Full Text: false
- Reviewed:
Complex coacervation with whey protein isolate and gum arabic for the microencapsulation of omega-3 rich tuna oil
- Authors: Eratte, Divya , Wang, Bo , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Food and Function Vol. 5, no. 11 (2014), p. 2743-2750
- Full Text: false
- Reviewed:
- Description: Tuna oil rich in omega-3 fatty acids was microencapsulated in whey protein isolate (WPI)–gum arabic (GA) complex coacervates, and subsequently dried using spray and freeze drying to produce solid microcapsules. The oxidative stability, oil microencapsulation efficiency, surface oil and morphology of these solid microcapsules were determined. The complex coacervation process between WPI and GA was optimised in terms of pH, and WPI-to-GA ratio, using zeta potential, turbidity, and morphology of the microcapsules. The optimum pH and WPI-to-GA ratio for complex coacervation was found to be 3.75 and 3 : 1, respectively. The spray dried solid microcapsules had better stability against oxidation, higher oil microencapsulation efficiency and lower surface oil content compared to the freeze dried microcapsules. The surface of the spray dried microcapsules did not show microscopic pores while the surface of the freeze dried microcapsules was more porous. This study suggests that solid microcapsules of omega-3 rich oils can be produced using WPI–GA complex coacervates followed by spray drying and these microcapsules can be quite stable against oxidation. These microcapsules can have many potential applications in the functional food and nutraceuticals industry.
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.
Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films
- 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.
Structural behaviour in condensed bovine serum albumin systems following application of high pressure
- Authors: Savadkoohi, Sobhan , Bannikova, Anna , Kasapis, Stefan , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 150, no. May (2014), p. 469-476
- Full Text: false
- Reviewed:
- Description: The present study shows that application of high hydrostatic pressure of 600 MPa for 15 min at ambient temperature on condensed bovine serum albumin systems (BSA) with up to 80% w/w solids content has a limited effect on the conformational structure of the protein, as compared to thermal treatment. This was demonstrated throughout the experimental concentration range using small-deformation dynamic oscillation, differential scanning calorimetry and infrared spectroscopy. BSA possesses seventeen disulfide linkages per molecule, which constitutes a stable arrangement with high energy requirements for substantial structure alteration. Upon cooling, pressurised materials undergo vitrification and networks exhibit comparative mechanical strength to that of thermally treated counterparts. The mechanical manifestation of the glass transition region and glassy state for atmospheric and pressurised samples was examined by the method of reduced variables and the combined framework of WLF/free volume theory producing disparate predictions of the glass transition temperature for the two types of polymeric network. © 2013 Published by Elsevier Ltd.