Investigation the effect of gamma irradiation pre-treatment on some qualitative and rheological properties of potatoes tuber

Irradiation is a modern method of food preservation. In this research were evaluated irradiation dose effect, shelf-life and storage time of on some qualitative and rheological properties of potatoes tuber. The samples were purchased from the store's Atomic Energy Organization and were stored for a week in the cold (4°C) in order to prevent chemical changes in the tissues. In order to samples irradiation was used cobalt-60 source (Gamma-cell 220). The samples were irradiated with 0 (control), 2, 5 and 8 kGy and then were storage for 150 days at a temperature of 6°C and at ambient temperature (18°C). Samples dry matter and starch content was higher for doses of 2 kGy and stored at a temperature of 6°C to 22.01 and 12.09 %, respectively. Geometric mean diameter and sphericity values ​​decreased with increasing radiation dose to 23.27 and 8.39 % and the dose of 8 kGy irradiated samples had the lowest values to 40.12 and 76.41 %, respectively. Also, a *, b *, color changes and BI increased by increasing the radiation dose to 2.9T 3.2T 5.13, 4.97 % and L* decreased to 2.14%, too. Moreover, three component model was calculated using by Maxwell Model and results show that with increasing dose of irradiation and temperature, relaxation stress decreased and relaxation time increased to 39.96 and 27%, respectively.