تاثیر تیمارهای مختلف بر تغییر رنگ و مدلسازی ریاضی رفتار خشک شدن ترخینه در خشک‌کن هوای داغ

Tarkhineh is one of the traditional products of western part of iran. this study was carried out in order to obtain more information on drying behavior of tarkhineh and find ways to improve drying condition. the influence of wheat cooking time (0, 1 and 3.5 hours), drying temperature (70, 80 and 90 °c), drying time (from 30 to 900 minutes) and bulgur particle size (fine, medium, coarse) on drying behavior of tarkhineh were studied. different mathematical models were applied to explain the drying behavior of tarkhineh. color changes of tarkhineh were determined by image j software. at the beginning of the drying process, the l* decreased while b* increased rapidly, however both reached a relative stable amount subsequently. a* slightly decreased initially but depending on the type of sample either increased or remained constant then. the results indicated that at 70 °c, the logarithmic model presented better predictions for modeling of mass( moisture) transfer than for ultra cooked samples but for raw and cooked samples, the two-term model were appropriate. at 80 and 90 °c, the two-term model was the best descriptive for ultra cooked samples but for raw and cooked samples, the midilli-kucuk model was appropriate. mentioned variables had major effect on the drying behavior of tarkhineh. for increasing the production rate and improving the color of tarkhineh, cooking of wheat for one hour and drying at 80°c can be recommended.