Determination of sugar, total phenol contents and antioxidant activity of various parts ‘Uzun’ pistachio cultivar (Pistacia vera L.)

Abstract

The aim of this study was conducted to determine the sugar content, total phenol and antioxidant activity of variousparts of ‘Uzun’ pistachio trees during 2018 (high bearing, or “on”-year trees) and 2019 (low bearing, or “off”-yeartrees) 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 contentof the samples were determined by the Folin Ciocalteu method by Spectrophotometer. Total antioxidant activitiyof samples were evaluated using the 1, 1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging method. Radicalscavenging 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. Thehighest 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 werein kernel (81,23% off-year) samples. Fructose content (12,10 g/100 g) was found to be higher than the contentsof 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 atphytochemicals in ‘Uzun’ pistachio variety has potent antioxidant activities that is important for human nutrition.