Optimization of the extraction method of the pistachio aroma compounds and effect of different hulling methods on aroma, aroma-active and phenolic compounds on pistachio

In this study, Uzun and Ohadi pistachio varieties, which were grown in Gaziantep province in 2012 year were used. At the beginning, the pistachio aromatic extract were obtained by three extraction techniques including solvent assisted flavor evaporation (SAFE), Likens-Nickerson, Purge-Trap. According to sensory analysis, the aromatic extract obtained by SAFE was the most representative of pistachio aroma, therefore this method was used for aroma extraction of pistachio samples. The effects of different hulling methods (dry, wet, wet-dry and brine), which were applied to pistachio, on the quality parameters of pistachio were studied. Initially, antioxidant capacity, total phenol, color, phenolic compounds and sensory properties of pistachios were analyzed. Then, aroma and aroma-active compounds, which characterized the pistachio, were determined by gas chromatography-mass spectrometry-olfactometry (GS-MS-O). Based on the findings, it was found that number and quantity of aroma and aroma-active compounds which characterized the pistachio, significantly depend on the hulling methods and pyrazines were the major aroma-active compounds in roasted pistachios. Briefly, dry hulling methods were detected as the best method for pistachio hulling process.