J Food Process Preserv. 2020;00:e14605. wileyonlinelibrary.com/journal/jfpp | 1 of 12 https://doi.org/10.1111/jfpp.14605 © 2020 Wiley Periodicals LLC. 1 | INTRODUCTION Pistachio (Pistacia vera L.) is one of the members of the Anacardiaceae family and shines among them due to its nutritious and delicious seeds (Salvador, Ojeda-Amador, & Fregapane, 2019; Sciubba et al., 2017). The root of the pistachio plant dates back to 80 million years ago and had two centers of origin; in central and western Asia. Additionally, it was estimated to have been cultivated for the first time by the Hittite, and then, spread to Spain and France during the Roman Empire era. Now it is cultivated in several countries with a Received: 6 February 2020 | Revised: 22 March 2020 | Accepted: 10 May 2020 DOI: 10.1111/jfpp.14605 ORIGINAL ARTICLE Comparison of phenolic profile and some physicochemical properties of Uzun pistachios as influenced by different harvest period Hasim Kelebek 1 | Ahmet S. Sonmezdag 2 | Gamze Guclu 3 | Nurten Cengiz 1 | Turkan Uzlasir 1 | Pinar Kadiroglu 1 | Serkan Selli 3 1 Department of Food Engineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana, Turkey 2 Department of Nutrition and Dietetics, Faculty of Health Sciences, Mugla Sitki Kocman University, Mugla, Turkey 3 Department of Food Engineering, Faculty of Agriculture, Cukurova University, Adana, Turkey Correspondence Hasim Kelebek, Department of Food Engineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana, Turkey. Email: hkelebek@atu.edu.tr Funding information Adana Alparslan Turkes Science and Technology University Research Found, Grant/Award Number: 18103003 Abstract Pistachios, which are among the top 50 healthiest foods, are rich in antioxidants and are a major source of phenolic compounds known for their related antioxidant ben- efits. The ripening stage is of paramount importance for food processing since the chemical composition of this fruit is heavily influenced by its level of maturity. For in- stance, immature pistachios are preferred to be used in desserts, sauces, ice-creams, and chocolate, while mature pistachios are more often consumed as a roasted snack. In this study, the changes in color properties, fatty acids, phenolic compounds, and antioxidant activity at four different maturity periods of the Turkish Uzun pistachio variety were investigated. A total of 13 phenolic compounds were identified and characterized by LC-DAD-ESI/MS n , with a total amount varying between 136 and 210 mg/kg. Catechin, daidzin, and genistin accounted for the highest amount of the total phenolics. The phenolic compounds and antioxidant capacities of the pistachios decreased as the maturation period extended and these two parameters displayed a linear correlation. With regard to fatty acids, Oleic acid had the highest concentration in all the samples, followed by Linoleic and Palmitic acids. The oil yield and fatty acids of pistachio also increased as maturation periods extended in the samples. Practical applications Pistachios have a high nutritional value and many health benefits, with their rich con- tent of phenolic compounds and fatty acids. The ripening period could lead to dif- ferences in phenolic compounds and other bioactive properties. The findings of this research could be helpful to determine the optimal maturity index of the pistachios for their usage in specific foods. Thus, it may lead to a decrease in production costs, with use of the most expensive ingredients becoming more efficient.