Effect of edible coating prepared from wild sage seed gum on the kinetics of color and surface changes of eggplant slices during frying process

The aim of this study was to investigate the changes in color parameters (L*, a*, b* and ΔE) and the area of eggplant slices coated with different concentrations of wild sage seed gum during deep fat frying. In this study, eggplant slices in a cylindrical shape with a thickness of 1 cm were coated using wild sage seed gum in three concentrations of 0.5, 0.5 and 1.5%. Then they were placed in the fryer and the effects of frying temperature at three levels of 150, 175 and 200 °C on the appearance characteristics of the samples were investigated. To examine the changes in color indexes including lightness (L*), redness (a*), yellowness (b*) and color changes (ΔE) as well as changes in the area of the samples, images were taken continuously during the frying time. The L* index calculated for the frying process of eggplant samples showed that the coated samples were brighter in terms of lightness and eggplants coated with wild sage seed gum with a concentration of 1.5% had higher L* values. With increasing the concentration of wild sage seed gum from 0.5 to 1.5%, the redness of the samples decreased from 11.77 to 8.38. In terms of color change index (ΔE), eggplants coated with wild sage seed gum showed the least color changes during frying. The mean ΔE values for the control sample, 0.5%, 1% and 1.5% of wild sage seed gum were 44.66, 46.25, 45.85 and 39.80, respectively. For modeling the color change index, the MMF model had less error compared to the Power, Quadratic, Gompertz, Logistic, Richards, and Weibull models and it fitted well with the experimental data. The average area changes calculated for the control sample, 0.5%, 1% and 1.5% of wild sage seed gum were 42.99, 40.49, 39.70 and 38.53, respectively.