Effect of ozone washing and UV irradiation on pesticide residues and physical and sensorial properties of dried slices produced by apples obtained from various regions of Urmia city

The aim of this research was to evaluate the efficiency of ozone washing and UV irradiation on the decreasing of pesticide residues in dried apple slices. For this purpose, four apple samples were collected from different regions of Urmia city including Shams hajian, Darre shohada, Balanej and Kashtiban. The effects of ozonation of whole apple and UV irradiation of its slices on the moisture content, bulk and true density, color indices and sensorial attributes were investigated. Also, the amount of pesticide residues in the fresh apple and dried slices was studied by GC-Mass analysis. Results indicated that there is no significant difference between moisture content of samples (p˃0.05). But both of growth region and applied pretreatments had significant effects on density and porosity of samples (p˂0.05). According to the evaluation of optical properties, the dried slices obtained from Balanej region had the highest color changes (50-64) and shrinkage (27-36 percent). Both of pretreatments improved the color indices of samples, but the effect of ozone was more than UV. Generally, the slices that were produced from Kashtiban region and by combination of ozone and UV had the lowest browning index (28.46) and achieved the highest sensorial scores. The residual pesticides were higher than standard limits just in the samples of Darreh shoahda and Balanej. Results indicated that the ozonation and UV irradiation were able to decrease the pesticide residues in the slices between 60 to 80 percent depending to the type of pesticide. In general, ozone washing and UV irradiation are effective methods in the decreasing of pesticide residues in the dried apple slices without negative effect on their sensorial characteristics.