The aim of this study was conducted to determine the sugar content, total phenol and antioxidant activity of various parts of ‘Uzun’ pistachio trees during 2018 (high bearing, or “on”-year trees) and 2019 (low bearing, or “off”-year trees) growing season. This research was carried on 35-year old, fruitful or unfruitful (showing alternate bearing) trees that were grafted on Pistacia vera rootstock at the Gaziantep provinces of Turkey. Total phenolic content of the samples were determined by the Folin Ciocalteu method by Spectrophotometer. Total antioxidant activitiy of samples were evaluated using the 1, 1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging method. Radical scavenging activities and total phenolic content of the samples changed depending on the different parts of shoot, leaves, nuts (hull and hard Shell) and kernel. Sugar compounds of Pistachio were detected by using HPLC. The highest antioxidant values were observed in hull (86,02% on-year) and hard Shell (85,37 % on-year ) and the lowest were in kernel samples. The highest total phenol amount was recorded hard Shell and the lowest values were in kernel (81,23% off-year) samples. Fructose content (12,10 g/100 g) was found to be higher than the contents of sucrose (3,10 g/100 g) and glucose (5,48 g/100 g) in ‘off’ year tree and the dominant sugar was found fructose. All tissues that the amount of sugar content in ‘off’ year was higher than ‘on’ year. The results suggest at phytochemicals in ‘Uzun’ pistachio variety has potent antioxidant activities that is important for human nutrition.
Free-radicals, Antioxidant, DPPH, Pistachio, Phenol, Sugar compounds