Characterization and comparative evaluation of volatile, phenolic and antioxidant properties of pistachio (Pistacia vera L.) hull

Pistachio hull is a good source of natural phenolics and antioxidants. Thanks to these bioactive molecules, the use of pistachio hull as nutritional ingredients in foods has attracted the interest of the food industry. In this study, phenolic compounds, antioxidant capacity, total phenol content, and volatile compounds were measured in the hull of two cultivars of pistachio, Uzun and Ohadi. LC-ESI-MS/MS method was used for the phenolic compounds analysis; 11 compounds were identified and quantified in the samples in which the major phenolic compound was gallic acid. The aroma composition of the pistachio hulls was isolated by SAFE (solvent-assisted flavor evaporation) method with dichloromethane and analyzed by GC-MS. Aroma compounds, including terpenes, acids, alcohols, phenols, and benzenes, were identified in both types of hulls, numbering 22 in the Uzun variety and 20 in the Ohadi. A significant linear correlation was confirmed between total phenolic compounds and antioxidant activity of hull extracts.