Evaluation of mechanical and optical properties of edible film from chickpea protein isolated (Cicer arietinum L.) containing thyme essential oil with response surface method (RSM)

The aim of this research, is consideration of producing edible film containing chickpea protein isolated and assigning of concentration effect on chickpea protein isolate, plasticizer concentration and percent of thyme essential oil on mechanical properties and color characteristics and transparency of edible film. Thus, evaluating isolated chickpea protein in range of 4 to 10 g, glycerol as plasticizer in concentrations between 40 to 60% and thyme essential oil in concentrations between 0 to 1% was carried out using response surface methodology. In this research, mechanical properties with food texture analyzer device and comparing color of film accomplished with hunter lab device for each sample six times. The results showed that tensile strength increased with increasing measure of chickpea protein isolated and decreased with increasing percent of glycerol and such results was vice versa for accepting elongation percent; glycerol had not any effects on the film color but increased the transparency of edible film significantly and increasing measure of chickpea protein isolated and thyme essential oil darkened the colored films and decreased the transparency factor (p<0.01). Continuance of optimization results which is based on chickpea protein isolated showed that to have desired tensile strength and equivalent 3.9503,high elongation and equivalent 62.1990,high transparency and equivalent 6.51 and minimum of difference of color to whiteness and equivalent 61.298;parameters of concentration of chickpea protein isolated 4gr,glycerol 60% and essential oil of thyme 0.13%.