Gamma radiation effects on phenolics, antioxidants activity and in vitro digestion of pistachio (Pistachia vera) hull

The effect of gamma radiation (10, 20, 30, 40, 50 and 60 kGy) on tannin, total phenolics, antioxidants activity and in vitro digestion of pistachio hulls has been investigated in this study. The possibility of using the radial diffusion method based on software measurement of the rings area has also been investigated in this study. The software based method in radial diffusion method showed a higher r2 (0.995) value when compared to the traditional method. Irradiation reduced the tannin content (P<0.01) and activity of antioxidants (P<0.05) of pistachio hull extracts but increased the total phenolic content (P<0.05). There was no effect of gamma irradiation on the in vitro digestion of the pistachio hull. Irradiation decreased the digestion rate of the pistachio hull at the dose of 40 kGy when compared to the control. This study showed that gamma irradiation decreased tannin and antioxidants activity of pistachio hull. - Highlights: → we investigate the effects of gamma irradiation on pistachio hull. → We examine changes in phenolics, antioxidant and digestion of pistachio hull. → Computerized radial diffusion method gives precise regression for standard curve. → Gamma irradiation will decrease tannin and antioxidants of pistachio hull extracts.