مدل سازي و اندازه گيري اثر سرخ كردن بر كيفيت خلال سيب زميني

چكيده انگليسي :

Modeling and measurement of deep frying effect on the quality of French fries Hamed Beyki h beyki@ag iut ac ir December 18 2012 Department of Food Science and Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Nasser Hamdami hamdami@cc iut ac ir Mohammad Shahedi shahedim@cc iut ac ir Abstract Considering the problems of preservation transportation and seasonal fluctuation of fresh potato production of ready to use products such as partial fried potato strips is of great importance The purpose of the current study was investigation of the effects of blanching and frying process on quality color texture reducing sugars moisture and oil content of potato strips of Agria variety For this purpose potatoes were cut into strips with dimensions of 0 8 0 8 8 cm after being washed and peeled Strips of group 1 were blanched for 120 minutes in distilled water at temperatures of 50 60 70 80 and 90 in two sub groups of without diffusion and with diffusion Strips of group 2 were fried in hot oil at temperatures of 160 175 and 190 after being blanched for 10 minutes at 70 and then pre dried at 70 with air velocity of 1 until mean moisture content of 75 wet basis The aforementioned quality characteristics were measured at different blanching times group 1 and frying times group 2 Then kinetic of quality characteristics were studied and appropriate mathematical models were selected for their description The results of the research were analyzed in perfect random statistical plan with factorial test and LSD mean comparison P 0 01 The results showed that increasing blanching temperature increases diffusion of reducing sugars and generation of these sugars due to enzymatic starch hydrolysis decreases with temperature increase No sugar generations were observed at temperatures of 80 and 90 Generation of reducing sugars increased diffusion coefficient of sugars significantly The effective diffusivity of reducing sugars was calculated in temperature range of 50 90 to be 1 45 5 13 10 10 Increasing the blanching time reduced colorimetric factors and tissue firmness significantly Increasing the frying temperatures increased a b factors oil uptake and decreased L factor moisture and reducing sugar content of strips Increasing of frying temperature also reduced core firmness and intensifying the process of crust development The final fried product was comprised of a soft core and a hard crust Studies showed that first order kinetic with production rate limiting effect had the most conformity with experimental data of texture firmness reducing sugar generation and a factor during blanching and moisture oil content and b factor during frying while zero order kinetic showed a better conformity with experimental data of core firmness in slow phase crust firmness and a factor during frying The kinetic of extraction of reducing sugar and b L factors variation during blanching core firmness in rapid phase and L factor during frying followed a first order kinetic The reducing sugar content of strips during frying followed an exponential kinetic According to the results of this research a product with desired quality could be obtained by 10 minutse of blanching at 70 and 5 minutes of frying at 160 Keywords Potato Strip Blanching Frying Pre drying Color Texture Reducing Sugar Diffusion Coefficient Modeling Mass Transfer

بيكي، حامد

مدل سازي و اندازه گيري اثر سرخ كردن بر كيفيت خلال سيب زميني

آنزيم بري , پيش خشك كردن , رنگ , بافت , قند احياء كننده , ضريب ديفوزيون , انتقال جرم