Papers by Zahra Emam-Djomeh
Food Hydrocolloids
A new gum was isolated from the roots of Acanthophyllum bracteatum (ABG) by warm-water extraction... more A new gum was isolated from the roots of Acanthophyllum bracteatum (ABG) by warm-water extraction. Purification was carried out by barium complexing to give a yield of 12.4% of pure air-dried or 5.8% of freeze-dried gum. The ABG contained 13.2% moisture, 84.3% carbohydrate, 0.9% protein and 1.5% ash. Its mineral content was comparable to commercial hydrocolloids. Monosaccharide analysis by HPLC showed the presence of galactose, glucose, arabinose, rhamnose and uronic acids in the ratio 16.0:7.2:3.0:1.0:3.1 respectively. The viscosity and pH value of 1% ABG solution at 25°C were 51.5mPas and 6.85 respectively. ABG solutions (5–30wt%) showed shear-thinning flow behavior at shear rates
Journal of agricultural and food …, 2009
No presente trabalho, objetivou-se avaliar o efeito dos métodos de cocção: cozimento em água (CA)... more No presente trabalho, objetivou-se avaliar o efeito dos métodos de cocção: cozimento em água (CA), fritura em óleo de soja (FO), assado em forno convencional (FC) e assado em microondas (MO) sobre perda de peso por cocção (PPC), composição química e colesterol em peitos de frangos das linhagens Super pesadão (Sp), Carijó (Cr) e Cobb (Cb). O delineamento experimental foi inteiramente casualizado, utilizando 3 linhagens, 5 métodos de cocção e 4 repetições, totalizando 60 parcelas experimentais. A PPC mais elevada foi verificada no método MO (52,35%), seguida pelo método FC (30,59%), FO (22,98%) e CA (19,99). A composição centesimal foi influenciada pelos métodos de cocção. Os peitos de frangos assados em MO apresentaram a menor umidade (56,18%) e médias mais elevadas de proteína (40,22%), cinzas (1,64%) e colesterol (63,89 mg/100 g), quando comparados aos demais métodos, comportamento observado em todas as linhagens. Os percentuais de gordura foram maiores no método FO, (3,23%; 2,53% e 1,94%, para as linhagens Sp, Cr e Cb, respectivamente). Peitos de frango assados em microondas mostram as perdas mais elevadas e as modificações mais severas com relação à composição química, enquanto a cocção em água é a forma de cocção que menos altera a composição centesimal de peitos de frangos. Termos para indexação: Cocção, aves, composição química. ABSTRACT The present work evaluated the effects of the cooking methods: boiling (BO), pan frying (PF), roasted in conventional oven (CO) and roasted in microwaves oven (MO) on the cooking loss, chemical composition, cholesterol in breast in different chickens strains: Heavy weight (Hw), Carijó (Cr) and Cobb (Cb). The completely randomized design by using 3 strains, 5 cooking methods and 4 repetitions and a total of 60 experimental parcel unit was used. The higher cooking loss most was showed in the method MO (52.35%), followed by the method CO (30.59%), PF (22.98%) and BO (19.99%). The centesimal composition was influenced by the cooking methods. The breast of chickens roasted in MO shown lowest moisture (56.18%) and the higher protein (40.22%), ashes (1.64%) and cholesterol averages when compared to the other methods, the same tendency of results were observed in all strains studied. The percentages of ethereal extract were higher in the method PF (3.23%; 2.53% and 1.94%, for the strains Hw, Cr and Cb, respectively. The chicken breasts cooking in the microwaves oven showed the highest losses and the most severe modifications in relation to the chemical composition, whereas the boiling is the cooking method show to be lower changes in the chemical composition of the chicken breasts
Ferula gumosa Boiss is one of the natural plants of Iran whose exudates (Barijeh) can be used in... more Ferula gumosa Boiss is one of the natural plants of Iran whose exudates (Barijeh) can be used in food industry. In the present study the properties of the gum extracted from tubers of Ferula gumosa were examined. For this purpose, gum was extracted from crude exudates by alcoholic extraction with 90% (v/v) ethanol. The purity of gum was relatively high, and it was composed mostly of polysaccharide. Soybean oil emulsions (10% w/w) were prepared using gum with concentration from 0.2 to 1.0 % (w/w). Surface tension, interfacial tension and creaming measurements were performed for all emulsions. Particle size measurements, light microscopy observations and rheological studies were performed for 1.0 % gum emulsion. The purified gum was found to reduce surface tension and interfacial tension of emulsions. Although particle size distribution measurements showed a slight change in particle size pattern after two month, mean diameter of particles remained constant. The creaming tests confirmed a comparatively good overall stability over a period of two months. The rheological measurements showed the shear thinning nature of emulsions prepared with the Barijeh gum. The emulsion stability was attributed to the surface adsorption mechanism.
American Journal of Plant Physiology, 2008
Advances in Water Resources, 1998
Preparative Biochemistry & Biotechnology, 2011
A thermostable isoenzyme (T80) of xylose isomerase from the eukaryote xerophyte Cereus pterogonus... more A thermostable isoenzyme (T80) of xylose isomerase from the eukaryote xerophyte Cereus pterogonus was purified to homogeneity by precipitation with ammonium sulfate and column chromatography on Dowex-1 ion exchange, with Sephadex G-100 gel filtration, resulting in an approximately 25.55-fold increase in specific activity and a final yield of approximately 17.9%. Certain physiochemical and kinetic properties (Km and Vmax) of the
Journal of Applied Research and Technology
Physical aging of semicrystalline polyethylene terephthalate was studied using differential scann... more Physical aging of semicrystalline polyethylene terephthalate was studied using differential scanning calorimetry(DSC). PET samples with crystallinity content of 0.28 were aged at two different temperatures, 25 and 45°C. Thesamples were stored for several days and periodically tested using DSC method. The glass transition temperature forthe samples aged at 25°C was about 73-74°C, and the position and intensity of endothermic peaks wereapproximately constant. Higher glass transition of the samples aged at 45°C, 73-86°C, was attributed to the enthalpyrelaxation process of amorphous regions of semicrystalline PET. For the samples aged at 45°C, the endothermicpeaks shifted to higher temperatures with increasing aging time. The position of the endothermic peaks determined bythe temperature of the maximum, Tmax, tended to increase with aging time for samples aged at 45°C, and theintensity of the peaks continuously increased with time; however, the results showed that the aging of PET sampl...
Research in Agricultural Engineering
In this study, Fick’s second law was used as a major equation to calculate the moisture diffusivi... more In this study, Fick’s second law was used as a major equation to calculate the moisture diffusivity for apricot fruit with some simplification. Drying experiments were carried out at the air temperatures of 40, 50, 60, 70, and 80°C and the drying air velocity of 1, 1.5 and 2 m/s. The experimental drying curves showed only a falling drying rate period. The calculated value of the moisture diffusivity varied from 1.7 × 10–10 to 1.15 × 10–9 m2/s for apricot fruit, and the value of activation energy ranged from 29.35 to 33.78 kJ/mol at different velocities of air.
Research in Agricultural Engineering
In this study, the dropping time of apricot fruits was followed experimentally using a water colu... more In this study, the dropping time of apricot fruits was followed experimentally using a water column. Some effective characteristics of apricots related to the dropping time were determined using standard methods. The best models for the dropping time of Nasiry, Rajabali, and Ghavami apricot varieties as a function of water and fruit densities, shape factor, and fruit volumes were executed with the determination coefficients of 0.95, 0.92, and 0.85, respectively. It was found that the differences between the fruits density minus the density of water had a major effect on their dropping time.
International journal of biological macromolecules, Jan 20, 2018
Nanostructured colloidal delivery systems comprising of pectin-coated nanoliposomes (pectonanolip... more Nanostructured colloidal delivery systems comprising of pectin-coated nanoliposomes (pectonanoliposomes) were developed as carriers for a bioactive polyphenolic compound (phloridzin). Phloridzin-loaded nanoliposomes were fabricated using a heating-stirring-sonication method, and coated with low methoxyl pectin using an electrostatic deposition approach. Dynamic light scattering, micro-electrophoresis, atomic force microscopy, and UV-Visible spectroscopy were used to investigate the impact of system composition on the size, charge, morphology and stability as well as immobilization, adsorption and encapsulation efficiencies of the pectonanoliposomes. Response surface methodology was used to optimize the composition of the pectonanoliposomes based on particle size and charge characteristics. Linear, quadratic and interaction effects of 1,2-dioleoyl-3-trimethyl ammonium propane/lecithin, phloridzin/lecithin and pectin/liposome ratios significantly influenced the mean hydrodynamic diame...
Journal of Nanoparticle Research
Journal of the Science of Food and Agriculture, 2016
To improve the quality of Pacific white shrimp (Litopenaeus vannamei), active coating solutions w... more To improve the quality of Pacific white shrimp (Litopenaeus vannamei), active coating solutions were prepared by dissolving 10 g L(-1) of basil seed gum (BSG) and adding various levels of thymol (6%, 8% and 10% w/w based on gum weight) and glycerol (3.5 g L(-1) ) as plasticizer. The effects of coating solutions (CS1-4) on the quality changes of shrimps during refrigerated storage over 20 days were investigated. The total volatile basic nitrogen (TVB-N) value in shrimps coated with CS4 (containing 10% w/w thymol) was slightly higher than the upper threshold of 300 mg kg(-1) on day 18, whereas that of uncoated shrimps increased to, or over, the threshold value on day 7. Active coatings significantly reduced (P < 0.05) microbial growth in shrimps during the cold storage without a negative impact on the organoleptic properties. Using CS4 on the shrimp samples immediately reduced total viable count and psychrotrophic bacteria count by 2 and 1 log colony forming units g(-1) , respectively, compared to controls. The results of the present study revealed that the active edible coatings based on BSG activated with thymol had good potential to be used in the production of active packaging for various food applications. © 2016 Society of Chemical Industry.
International journal of biological macromolecules, Jan 13, 2016
The main objective of this work was to investigate the effects of polysaccharide type (gum Arabic... more The main objective of this work was to investigate the effects of polysaccharide type (gum Arabic, GA and/or carboxymethyl cellulose, CMC) and concentration (0-0.2% (w/w)) on the electrostatic interactions with β-lactoglobulin (BLG). Biopolymer interaction was studied using turbidimetric analysis, dynamic light scattering (DLS), electrophoretic mobility and relative viscosity measurements. Complexes were developed at pH values below the isoelectric point (pI) of BLG. Increasing polysaccharide concentration increased the stability of nanocomplexes through increasing the negative charges carried by complexes. The differences between GA and CMC were attributed to the polysaccharide structure (linear or branched chains), charge density and flexibility. Phase contrast optical microscopy showed that complexation was of nucleation and growth type mechanism. Relative viscosity measurements confirmed that wrapping phenomenon occurred in both associative mixtures.
Journal of Microencapsulation, 2016
The present study was performed to optimise the formulation of a muco-adhesive buccal patch for i... more The present study was performed to optimise the formulation of a muco-adhesive buccal patch for insulin nanoparticles (NPs) delivery. Insulin NPs were synthesised by an ionic gelation technique using N-di methyl ethyl chitosan cysteine (DMEC-Cys) as permeation enhancer biopolymer, tripolyphosphate (TPP) and insulin. Buccal patches were developed by solvent-casting technique using chitosan and gelatine as muco-adhesive polymers. Optimised patches were embedded with 3 mg of insulin-loaded NPs with a homogeneous distribution of NPs in the muco-adhesive matrix, which displayed adequate physico-mechanical properties. The drug release characteristics, release mechanism and kinetics were investigated. Data fitting to Peppas equation with a correlation coefficient indicated that the mechanism of drug release followed an anomalous transport that means drug release was afforded through drug diffusion along with polymer erosion. In vitro drug release, release kinetics, physical and mechanical studies for all patch formulations reflected the ideal characteristics of this buccal patch for the delivery of insulin NPs.
Uploads
Papers by Zahra Emam-Djomeh