Effect of hulling methods and roasting treatment on phenolic compounds and physicochemical properties of cultivars 'Ohadi' and 'Uzun' pistachios (Pistacia vera L.)

The aim of this study was to identify phenolic compounds and measure the physicochemical properties of two pistachio (Pistacia vera L.) cultivars ('Uzun' and 'Ohadi'). For this purpose, the pistachios were subjected to four different hulling methods (wet hulling-WT, brine hulling-BR, wet-dry hulling-WD, and dry-dry hulling-DD) and a standard roasting treatment. Phenolic compounds were analyzed by HPLC-DAD-ESI-MSn. Twelve phenolics were identified and quantified in the samples, 10 of which were flavonoid and two non-flavonoid phenolic acids. In both cultivars, the major compounds were found to be gallic acid and catechin followed by eriodictyol-7-O-glucoside and eriodictyol. The dry-dry hulling method treated sample had higher antioxidant capacity, total phenol content, and phenolic compounds than the other hulling methods in both pistachio cultivars. After the roasting treatment, the antioxidant capacity, phenolic content, and a∗ value increased while the L∗ and b∗ values decreased.