Unlocking the aroma compounds of pistachios using the power of multi-dimensional gas chromatography

The quality and consumer acceptance of pistachios heavily rely on their distinctive aroma, which serves as a crucial organoleptic characteristic. Similar to other natural products, the aroma of pistachios is influenced by numerous factors, including the cultivar, geographical origin, harvesting conditions, and storage methods. The majority of pistachio production occurs in countries with warm and arid climates. Notably, Iran, the United States (USA), Italy, Greece, Tunisia, Turkey, Syria, and Spain stand out as the world's leading pistachio producers. Characterizing the unique aroma profiles of pistachios is essential not only for consumer acceptance but also for establishing standardized production processes in the industry. In this particular study, the volatile organic compounds (VOCs) present in pistachios sourced from various geographic locations were evaluated. The assessment employed a high-capacity concentration (HCC) tool called HiSorb™, which bridges the gap between solid phase micro-extraction (SPME) and stir bar sorptive extraction (SBSE), thereby enhancing sensitivity and repeatability through its automated and user-friendly interface. Different HiSorb™ probes were assessed to determine the optimal parameters, including extraction temperature and duration. Subsequently, the VOCs extracted using HiSorb™ were subjected to two-dimensional comprehensive gas chromatography-mass spectrometry (GC×GC-MS) analysis, utilizing a reversed fill/flush flow modulator. The use of multidimensional gas chromatography enhances the separation power and maximizes the amount of information obtained, resulting in a comprehensive chromatographic fingerprint of the VOCs present in pistachios.