3592

3395

كارشناسي ارشد

علوم و صنايع غذايي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1385

جهارده، 96، [II] ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

محمد شاهدي، ناصر همدمي

شهرام دخاني، مرتضي صادقي

86/4/27

مهدي كديور، امين الله معصومي

1396/02/26

كتابنامه

كشاورزي

مهندسي كشاورزي

ID3395

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractDrying of agricultural products has always been of great importance for thepreservation of food by human beings Sun drying is a well known food preservationtechnique that reduces the moisture contents of agricultural product and therebyprevents deterioration within a period of time regarded as the safe storage period Since all fresh tomatoes can not be consumed at the time of harvest preservationprovides a larger market allowing consumers to buy the preserved tomato around theyear Tomatoes may be dried using either solar energy or mechanical systems Traditional sun drying is a slow process compared with other drying methods but it issaid to give dried tomatoes their distinctive quality Simulation models are helpful indesigning new or in improving existing drying systems or for the control of the dryingoperation A natural convection solar dryer consisting of a solar air heater and adrying chamber was manufactured in this research Tomato slices were dried in thesolar dryer and compared with open sun drying Also tomato slices were dried in alaboratory oven Effective water diffusivity values ranged from 2 05 10 10 to 7 74 10 11 m2 s The results showed that drying time in the solar dryer is shorter than opensun drying Shrinkage and rehydration ability of food materials during air dryingadversely affects the quality of the dried products The experimental shrinkage datashow a linear behavior with moisture content with a reduction in sample volume withdecreasing moisture content The effect of temperature on the shrinkage phenomenoncan thus be neglected The experimental data didn t show the dominating effect oftemperature on the rehydration ability of this product The influence of temperatureon the rehydration ability can thus be neglected The drying data as the moisture ratio MR versus drying time were fitted to the 13 thin layer drying models Thecomparison criteria used to evaluate goodness of fit namely the coefficient ofdetermination R2 the root mean square error RMSE and the reduced chi square 2 The Wang model for oven drying and the Page model for sun drying gave higherR2 and lower RMSE and 2 values than other models Finally a numerical model wasdeveloped to simulate the moisture transfer during thin layer drying of tomato slicesby finite difference method on MATLAB software The predicted water loss contentwas validated by comparison with the experimental values R2 0 98 It can beconcluded that this model describes well the mechanism of moisture diffusion in aone directional transfer during thin layer drying of tomato slices

محمد شاهدي، ناصر همدمي

شهرام دخاني، مرتضي صادقي

مهدي كديور، امين الله معصومي