توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Influence of enzymatic parameters on yield of carrot juice
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
In this work, the effect of enzymatic treatment on process of juice extraction from carrot was studied. The enzymatic process consisted of the treating blanched chopped carrot at specified pH with Pectinex Ultra SP–L enzyme. The influences of various parameters such as enzyme concentration (10–5000ppm), pH (3.76–5.1), and enzymatic incubation time (30–120min) and temperature (25–60°C) on carrot juice extraction yield were investigated. Results showed that enzymatic treatment had impressively effect on carrot juice yield. Enzymatic incubation temperature and pH had not considerable effect on carrot juice yield, but enzyme concentration and enzymatic incubation time had significantly effect on juice extraction yield. The optimum conditions for enzymatic treatment were determined.<\div>

۲Clarification of carrot juice with membrane and enzymatic processes
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
Enzymatic hydrolysis and ultrafiltration (UF) membrane process were used as two techniques for clarification of carrot juice. An appropriate process for clarification with high permeates flux and low membrane fouling was achieved by enzymatic pretreatment of juice before UF membrane filtration. Permeate flux increased with enzymatic treatment followed by UF membrane filtration. The resulting juice after filtration had more than 90% clarity without deterioration of important quality index in juice e.g. pH, and total soluble solid.<\div>

۳Concentration of Carrot Juice using Osmotic Membrane Distillation Process
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۶
This study was undertaken in order to evaluate the potential of the osmotic distillation (OD) process for concentration of carrot juice on laboratory scale. The performance of the OD process in terms of flux and concentration factor was evaluated. Carrot juice with an initial TSS (Total Soluble Solid) content of 7o Brix was concentrated up to values of 30oBrix using a osmotic distillation membrane contactor with PTFE flat sheet membranes. Aqueous solution of calcium chloride dehydrate at 50 w\w% was used as stripping solution producing an initial evaporation flux of about 10 kg\m2 h. The experimental data showed that at low total soluble solids concentration the evaporation flux decay was more attributable to the dilution of the stripping solution, while at high TSS value of feed, the evaporation flux depended mainly on juice viscosity and consequently, on juice concentration.<\div>

۴Preparation and characterization of antibacterial polyethersulfone ultrafiltration membrane
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
The aim of this study is to develop a polyethersulfone (PES) nanocomposite membrane with antimicrobial activity for using in food industries. For this purpose, PES ultrafiltration membranes were prepared via phase inversion induced by immersion precipitation technique. Then silver nanoparticles were coated on the PES membrane surface by immersion in the colloidal silver solution that synthesized by chemical reduction of silver nitrate salt. Surface properties of the prepared PES membranes were examined by AFM and FESEM analysis and the amounts of coated silver and silver ion release from nanocomposite surface were determined by atomic absorption. The ultrafiltration performance of nanocomposite membrane was evaluated by a cross flow flat sheet UF membrane unit. The results indicated that coating PES membranes with nano silver the water permeation flux decreased from 8.85 to 5.55 kg\hr.m2, and the AFM images indicated that RMS of the coated membrane were decreased from 15.07 to 7.2 nm. This result confirms flux decrease of the nano silver coated membrane. Also, the quantity of silver ion release in the permeate and retentate streams was 12.3 and 12 μg\lit.hr, respectively<\div>

۵Preparation of colloidal silver nanoparticles with antibacterial activity by a simple chemical reduction method
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۹
In this study, a simple method for preparation of silver nanoparticles was proposed and the stability and properties of nanoparticles were investigated. In this method, trisodium citrate was used as a reducing agent. The effect of various experimental parameters such as temperature andpH on the particle size and stability of nanoparticles was studied. The morphology of silver nanoparticles was characterized by high resolution FE–SEM which showed the formation of silverparticles in the nano form. The absorption spectra of silver nanoparticles prepared by the proposedtechnique showed an absorption maximum at 432 nm in UV–Vis spectrometry, which is a typical absorption band of spherical silver nanoparticles. Besides, the antibacterial activity of silver nanoparticles was evaluated by agar well diffusion method.<\div>

۶Modeling of microwave heating of mashed potato with temperature dependent thermal and dielectric properties
نویسنده(ها): ، ،
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۱۲
Microwave processed foods are becoming increasingly popular in the market. There is a definite need to develop a method based on rational principles that will allow researchers to analyze the heat and mass transfer and to locate hot and cold spots during microwave heating. In order toanalyze the temperature distribution in a sample processed by microwave heating, a mathematicalmethod was developed to solve the unsteady state two–dimensional heat transfer equation in variusgeometry. The Lambert’s law was used to model the heat generation of microwave heating. The numerical solution was developed using an implicit finite difference method in transient two dimensional systems to predict temperature profile in the potato samples. In this study, thermal and electromagnetic properties were considered temperature dependent whicd led to a non–linearpartial differential equation. Influnce of sample size and processing time on the temperature profile and location of hot and cold spots were evaluted. Finally, the porposed model was validated with published exprimental data and other mathematical models<\div>

۷Effect of fabrication parameters on the performance zeolite filled composite pervaporation membranes
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
The aim of this study is to develop a new pervaporation membrane for dehydration of ethanol\water mixture and to investigate the effect of preparation parameters on the membrane performance. Zeoiltes NaX are added az fillers to the base polymer, polyethersulfone (PES). Membranes were preparaed by solvent evaporation method and anealed above the glass transition temperature (Tg) of PES. The performance of the fabricated membrane was evaluated by pervaporation of a ethanol\water solution at constant feed temperature and permeate pressure. The results showed that incorporation of zeolite NaX to neat PES membarnes resulted in higher permeabilites, but by adding more zeolite the selectivity decreased compare to the neat PES. It was obseved that annealing strongly affect the performance of membarnes<\div>

۸Effect of modified atmosphere packaging on bread staling
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۶
Though modified atmosphere packaging (MAP) is known to extend microbial shelf life of bread but its effect on staleness of bread is not properly recognized. In this work, the application of MAP for hamburger bread buns at room temperature was studied and the effects of MAP on the bread staling were investigated. Four atmospheres including 20%, 40% and 80% of carbon dioxide balanced with N2 as filler and less than 2% O2 and a normal air as control were used. The bread samples were packed in pouches made from impermeable polymeric film of polyethylene–polyamide–polyethylene (PE–PA–PE) with total thickness of 80 μm and stored at room temperature for 12 days. Staleness and headspace composition of bread samples were analyzed. Results obtained here confirm that MAP of bread had no significant effect on bread staleness. However, any signs of molding did not appear in the bread samples except control ones. The variations in headspace composition of samples explained that bread crust adsorbs CO2<\div>

۹Effect of temperature and modified atmosphere on drying kinetics and color of dried golden apple
اطلاعات انتشار: هفتمین کنگره ملی مهندسی شیمی، سال
تعداد صفحات: ۸
Drying is one of the widely used techniques of vegetables and fruits preservation. The aim of this work was to determine the effect of drying temperature and modified atmosphere on the dehydration time and color of convection dried apples. For this purpose, apples dried under air and inert environmental (nitrogen) condition at temperature in the range from 60 to 80˚C. The colors of samples are investigated by a computer vision system that composes of a digital color camera for recording image in a digital format and a computer for storage the images. The sample color in RGB system converts into L*a*b* unit using a matlab program. Color analysis showed that dried samples at 60˚C have the less browning and total color differences. The dehydration ratio decreased with an increase in the drying temperature<\div>

۱۰Investigation on effect of corona plasma treatment conditions on surface modification of polyethersulfone ultrafiltration membrane
اطلاعات انتشار: دومین کنفرانس بین المللی و سومین همایش ملی کاربرد فناوری های نوین در علوم مهندسی، سال
تعداد صفحات: ۵
Membrane surface modification is a useful technique to improve the separation performance and reduce the fouling tendency of the polymeric membranes. The main goal of this work is to modify the surface of polyethersulfone (PES) ultrafiltration (UF) membrane by corona air plasma treatment as a cold plasma technique. For this purpose, the PES UF membranes were prepared by the non–solvent–induced phase inversion method using water as non–solvent and then the surface of the prepared membranes were modified by the corona air plasma. The influence of corona input power (180, 270 and 360 W) and corona exposure time (2, 4 and 6 min) on the membrane surface properties was investigated. The modified membranes were characterized by the SEM, AFM and contact angle analysis as well as the pure water UF permeation and swelling tests. The results indicated that the surface porosity of the PES membrane enhanced by the corona surface modification. It was observed that at constant corona treatment time, the surface roughness of the membranes increased when the corona input power varied from 180 to 360 W. Furthermore, an increase in the corona power and exposure time resulted in higher hydrophilicity of the membrane surface. The pure water flux of the unmodified PES membrane and the membrane treated at 360 W for 6 min was 6.78 and 18.8 kg\m2h, respectively.<\div>
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