6940

6482

كارشناسي ارشد

علوم و صنايع غذايي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1390

يازده، 208ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

ناصر همدمي، محمد شاهدي

علي نصيرپور

21/5/91

جواد كرامت، مرتضي صادقي

1396/09/18

كتابنامه

كشاورزي

مهندسي كشاورزي

ID6482

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

1 Mathematical Modeling of Baking in Part Baked Sangak Bread Farzad Sadeghi F Sadeghi@ag iut ac ir March 5 2011 Department of agriculture Isfahan University of Technolgy Isfahan 84156 83111 Iran Degree M Sc Language FarsiN Hamdami N Hamdami@ag iut ac irAbstractThe role of bread in economy and nutrition of human life has always been inevitable Among theIranian breads the Sangak bread has a distinguish nutritional value and a special taste with greatpotential for industrial production Baking is one of the important and complex processes in breadmaking Many phenomena such as evaporation dough volume rising starch gelatinization protein denaturation and crust forming occur in baking This research was carried out for betterunderstanding these phenomena In the first part of this work the impact of fermentation time baking temperature and time on the quality properties of Sangak bread pores distribution apparent volume density water activity crust and crumb firmness and crust color wasdetermined The results showed that I increasing the baking time reduces the moisture content water activity density crumb firmness and crust lightness and increases volume porosity crustfirmness a and b II increasing the fermentation time increases the volume porosity and a b andL and III increasing the baking temperature reduces density moisture content water activity andL and increases the porosity volume crumb and crust firmness a and b In the second step amultiphase model for simultaneous heat and mass transfer in porous medium was developed tosimulate the baking process for part baked Sangak bread The model was based on Fourier s lawfor conductive heat transfer and Darcy s and Fick s laws for mass transfer of liquid water andgas water vapor and CO2 phases Numerical Finite Element Method FEM scheme was used tosolve the equations The numerical procedure was implemented in COMSOL Multi physics v3 5software Then thermophysical properties thermal conductivity specific heat enthalpy initialfreezing temperature and density of Sangak bread during baking were determined and modeled One of the most important thermophysical properties is thermal conductivity A line heat sourceprobe was used to measure thermal conductivity According to experimental data thermalconductivity decreases during baking as porosity increases and moisture content decreases Tomodel the thermal conductivity four predictive models for porous food were selected anddeveloped series parallel Krischer and Maxwell models The effective thermal conductivitypredicted by Krischer model was in good agreement with the experimental data Finally tovalidate the model the predicted temperature profiles in different parts of bread were comparedwith experimental results Results showed a good agreement between experimental and numericalresults Key wordBread baking Color Density firmness Modeling Moisture content Porosity Thermal conductivity Volume Water activity

ناصر همدمي، محمد شاهدي

علي نصيرپور

جواد كرامت، مرتضي صادقي