The Effect of Gamma Irradiation on Phytochemical Content and Antioxidant Activity of Stored and None Stored Almond (Amygdalus communis L.) Hull

Background: Gamma radiation has been widely used as a post-harvest food preservation process for many years. Irradiation can affect the content of phytochemicals. During processing of almonds, large amounts of by-products such as hull and shell are produced. This study evaluates the effect of gamma radiation on phytochemical content and antioxidant activity of none stored (H1) and stored (H2) almond hull. Methods: Both almond hull samples were irradiated with 0, 2, 6 and 10 kGy gamma rays. Total phenolic content (TPC), total flavonoid content (TFC) and bioactivity of the treated samples extracts were investigated by various In vitro colorimetric methods. Results: Irradiation dose of 10 kGy slightly decreased the TPC and TFC values but maintained FRAP value in H1 extracts. The TPC of H2 was increased (p<0.05) at the dose of 10 kGy, while the TFC and FRAP values were constant. 2 kGy dose of gamma irradiation slightly increased the antiradical activity of H1 and H2, but the other doses significantly reduced antiradical activity of extracts. Conclusion: Results showed that gamma irradiation can change the antioxidant content and activity of almond hull.