Evaluation of physical and chemical changes in stuffed grape leaves during storage in terms of reaction kinetics

Shelf life of stuffed grape leaves was determined by conducting accelerated shelf life tests. Stuffed grape leaves was stored at 25οC, 35οC ve 45οC and The changes in color, texture, hydrolitic rancidity, p-anisidin value of stuffed grape leaves were followed. The findings were evaluated by chemical kinetics. As a result, it was determined that the changes of L and p-anisidine values were occured according to a zero order reaction kinetics while changes of Hue and hydrolotic rancidity values were detemined to fit first order kinetic model. Textural properties of stuffed grape leaves were changed significantly during storage depend on storage temperature. However, it was deternied that the changes in textural properties was not fitted any chemical kinetic model. The activation energies (Ea) of the changes in L, Hue, hydrolitic ransidity and p-anisidine values were calculated as 36,85, 29,18, 34,12 ve 50,81 kJ mol-1, respectively. According to this, p-anisidine value was accapted as a critical quality parameter for stuffed grape leaves and modelling of shelf life was established by considering Arrhenius equation. Based on 20, 25 and 30 critical p-anisidine values, the shelf life of stuffed grape leaves at the storage temperature of 25οC were calculated as 221,28, 313,02 ve 407,70 days.