Effect of ultraviolet radiation on some quality characteristics of dry pistachio kernel

There are different ways to reduce the risk of spoilage and increase the shelf life of agricultural products, one of which is ultraviolet radiation. The UV irradiation system has seven UV-C lamps, that for microbial deactivation, the effects of lamps number (3, 5 and 7), the distance of lamps from pistachio kernels (10, 20 and 30 cm), and the UV-C radiation time (15, 20 and 30 minutes) were evaluated. Based on Aspergillus flavus inactivation, the application of 3 lamps, the distance of 10 cm, and the irradiation time of 30 minutes were selected as the best treatment for irradiation of dry pistachio kernels. The results indicated that UV-C irradiation had no significant effect on peroxide and acidity values (p <0.05), but UV-C irradiation caused a significant (p<0.05) increases of the total phenolic content in pistachio kernels. According to the panelists scores, the texture of irradiated sample obtained a higher score than the control sample. However, no significant difference was observed in terms of other sensory characteristics (appearance, aroma, and taste) between the irradiated and control samples.