Kinetics of Color and Physical Attributes of Cookie during Deep-Fat Frying by Image Processing Techniques

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 zero‐order 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. Practical Application The physical properties of cookie such as color and texture have so important for consumers of food products. Since, texture measurement during processing is a time‐consuming and destructive technique, finding another method for its evaluating will be beneficial. Therefore, the correlation between color and texture of cookie during deep‐fat frying by applying image processing techniques was investigated. It was found a good correlation for L* and ΔE with texture than internal porosity. The activation energy of internal porosity was lowest of all the physical properties. It seems the L* can be reliably used to predict the hardness of deep‐fat fried cookie. Therefore, by having enough knowledge on surface color of cookie, it will be possible to estimate texture properties.