Survival, fermentation activity and storage stability of spray dried Lactococcus lactis produced via different atomization regimes
- Authors: Ghandi, Amir , Powell, Ian , Broome, Melcolm , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 115, no. 1 (2013), p. 83-90
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- Description: Dried powders containing Lactococcus lactis ssp. cremoris were produced using laboratory and pilot scale spray dryers with lactose:whey protein isolate (3:1) as a protective medium. The effects of storage temperature (25, 4 and -18 °C) and time (30, 60 and 90 days) were studied. The survival and fermentation activity of the dried bacterial cells were significantly lower when the powders were stored at 25 °C compared to those stored at 4 and -18 °C; powders stored at 4 and -18 °C were statistically similar. The survival and fermentation activity of bacterial cells obtained from a laboratory scale two-fluid nozzle spray dryer were found to be higher than those of cells obtained from a pilot scale two-fluid spray dryer. A rotary wheel atomizer gave significantly higher survival and activity in the same dryer. These observations are consistent with cell damage due to high characteristic shear rates in the atomization process in nozzle type atomizers. The presence of ascorbic acid (oxygen scavenger) in the powder composition was found to improve both the survival and the maintenance of fermentation activity of the dried bacterial cells significantly during storage. The survival and fermentation activity of dried bacterial cells in stored powders indicated that these parameters are system-specific and can be strongly affected by the storage temperature and presence or absence of antioxidant, and also by upstream processing conditions such as the mode of atomization and presence or absence of antioxidants in the dryer feed. © 2012 Elsevier Ltd. All rights reserved.
- Description: 2003010581
Extending shelf-life of fresh-cut green peppers using pressurized argon treatment
- Authors: Meng, Xiangyong , Zhang, Min , Adhikari, Benu
- Date: 2012
- Type: Text , Journal article
- Relation: Postharvest Biology and Technology Vol. 71, no. (2012), p. 13-20
- Full Text: false
- Reviewed:
- Description: When fresh-cut fruit and vegetables are subjected to pressurized argon treatments, the argon gas dissolves into water and forms clathrate hydrates which ultimately lead to restriction in water mobility. In this study, fresh-cut green peppers were subjected to pressurized (2-6MPa) argon treatments for 1h. The untreated (control) and argon-treated samples were placed in polystyrene packaging with 5% O 2 and 8% CO 2 and then stored at 4°C and 90% RH for 12d. Various quality parameters of fresh-cut green peppers treated at 2, 4 and 6MPa of argon were compared with those of the control. Water loss, ascorbic acid loss, visual sensory quality, malondialdehyde (MDA), cell membrane permeability, cell protective enzyme activity and microbial quality were determined every 2d. Water mobility and loss of water in fresh-cut green peppers was greatly reduced by the pressurized argon treatment. Similarly, the loss of ascorbic acid, chlorophyll content and hue angle was also reduced during storage. The pressurized argon treatments were found to maintain the cell integrity by inhibiting an increase in MDA and membrane permeability compared to the control samples. The activities of catalase (CAT) and peroxidase (POD) were inhibited by the pressurized argon treatment. The treatment also reduced proliferation of spoilage microorganisms such as coliforms, yeasts and moulds. The fresh-cut green peppers treated by pressurized argon at 4MPa for 1h could be kept in a fresh-like condition for 12d at 4°C. © 2012 Elsevier B.V.
Preparation and characterization of crosslinked starch microspheres using a two-stage water-in-water emulsion method
- Authors: Li, Bingzheng , Wang, Lijun , Li, Dong , Adhikari, Benu , Mao, Zhihuai
- Date: 2012
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 88, no. 3 (2012), p. 912-916
- Full Text: false
- Reviewed:
- Description: Crosslinked starch microspheres (CSMs) were prepared using a novel two-stage water-in-water emulsion method (WWEM). The results show that the yield and crosslinking density of CSMs were affected significantly (p < 0.05) by molecular weight and concentration of polyethylene glycol (PEG) in continuous phase, crosslinker concentration as well as incubation time. The increase in any one of these variables resulted into increase in the crosslinking density. The yield and crosslinking density of CSMs prepared by WWEM (WWEM-CSMs) were lower than those prepared by water-in-oil emulsion method (WOEM). The morphology, chemical composition and amorphous/crystalline nature of the CSMs were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). SEM analysis indicated that the WWEM-CSMs were spherical, compact and nonporous in nature. FTIR and XRD analysis indicated that WWEM-CSMs were PEG-free and amorphous in structure. These characteristics were very similar to the characteristics of CSMs prepared by WOEM. © 2012 Elsevier Ltd. All rights reserved.
Effect of flaxseed meal on the dynamic mechanical properties of starch-based films
- Authors: Wu, Min , Wang, Li-jun , Li, Dong , Mao, Zhihuai , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 118, no. 4 (2013), p. 365-370
- Full Text: false
- Reviewed:
- Description: Starch (S)-flaxseed meal (FM) biofilms were prepared from potato and maize starch by incorporating FM up to 15% (dry solid basis) and using glycerol as plasticizer. The dynamic mechanical properties, tensile properties and water vapor permeability (WVP) of these films were measured. The storage modulus of both the starch (control) and starch-FM films decreased as temperature increased. Tan
- Description: 2003011095
Interfacial and emulsifying properties of lentil protein isolate
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan , Barrow, Colin
- Date: 2012
- Type: Text , Journal article
- Relation: Food Chemistry Vol.134 no.3 (2012), p.343-1353
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- Description: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas > LPI > WPI > BSA > Lys, while their surface hydrophobicity was in the following order: BSA > LPI > NaCas > WPI > Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m 2/g and it was 93.3 ± 0.2 m 2/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents. © 2012 Elsevier Ltd. All rights reserved.
Preparation and characterization of glycerol plasticized (high-amylose) starch-chitosan films
- 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
- Full Text: false
- Reviewed:
- 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
Microencapsulation of alpha-Amylase by carrying out complex coacervation and drying in a single step using a novel three-fluid nozzle spray drying
- Authors: Jiang, Hao , Zhang, Min , McKnight, Stafford , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Drying Technology Vol. 31, no. 16 (December 2013 2013), p. 1901-1910
- Full Text: false
- Reviewed:
- Description: The aim of this research was to develop an enzyme encapsulation process in which both the complex coacervation and drying processes are combined into a single step. For this purpose, we used a novel three-fluid nozzle at the atomization step of spray drying. -Amylase as a model enzyme was encapsulated by coacervation in calcium (Ca) alginate and Ca-alginate+chitosan shell matrices and the powder was obtained in a single step through spray drying. The single-step process was compared to carrying out the complex coacervation and drying processes in two steps using freeze drying, in which -amylase was encapsulated by carrying out the complexation process in the above-mentioned shell matrices using the same three-fluid atomizer and collecting the coacervates, which were subsequently freeze dried. The results showed that the microcapsules obtained from the single-step encapsulation process (three-fluid nozzle spray drying) had smaller particle sizes, were less porous, and provided better enzyme stability compared to the microcapsules obtained by carrying out the complexation and drying in two steps and the single-step process was faster. It was observed that the egg-box structure was formed in both types of powder particles; however, the complexation with chitosan partially disrupted the formation of this structure. The three-fluid nozzle-based spray drying is a promising technology in which both the complex coacervation and drying processes can be carried out in a single step.
- Description: C1
The effect of partial gelatinization of corn starch on its retrogradation
- Authors: Fu, Zong-qiang , Wang, Li-Jun , Li, Dong , Zhou, Yuguang , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 97, no. 2 (2013), p. 512-517
- Full Text: false
- Reviewed:
- Description: The objective of this work was to investigate the effect of partial gelatinization of starch on its retrogradation using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. The Avrami equation was used to predict the evolution of starch retrogradation kinetics. The degree of retrogradation in starch samples partially gelatinized 64 ?C (S64), 68 ?C (S68) and 70 ?C (S70) and control (S25) increased with storage time. The retrogradation enthalpies of S68 and S70 were almost four times as high as that of S64. The S25 and S64 had dominant A-type crystalline pattern while S68 and S70 showed dominant B-type crystalline pattern. The growth of remainder crystals was faster in S25 and S64, while both the nucleation and growth rates of new crystals were faster in S68 and S70. The Avrami model was found to represent the retrogradation kinetics data of these partially gelatinized starch samples quite satisfactorily (R2 > 0.95). © 2013 Elsevier Ltd. All rights reserved.
- 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 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.
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
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
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.
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.
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.
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.
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
- Full Text:
- 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.
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.
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).
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.