Deep-fat frying is one of the most prevail methods of food processing, which affect color and physical properties. The effects of frying temperature -150–180C- and time on the physical characteristics of cookie, including crust thickness, internal porosity, color and hardness, have been investigated. Kinetics of color and physical attributes of cookie were investigated using zero/first order of kinetics. Crust color was also evaluated and L*, a*, b* and ΔE, values were obtained. Further, rheological property of crust surface, i.e., hardness was examined. Hardness and L*, followed a first-order change, while the other parameters had zeroorder kinetics. The temperature dependence of reaction’s constants explained by the Arrhenius equation and activation energy was found to be in the range of 21.2–92.86 kJ/mol. The L*, crust thickness and ΔE had higher correlations with texture than internal porosity, which suggests that L* can reliably be used to predict the hardness of deep-fat fried cookie.

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