ARS | Publication request: Essential oil yield and composition of Pistacia vera "Kerman" fruits, peduncles, and leaves grown in California

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 16, 2009
Publication Date: January 25, 2010
Citation: Dragull, K.D., Beck, J.J., Merrill, G.B. 2010. Essential oil yield and composition of Pistacia vera "Kerman" fruits, peduncles, and leaves grown in California. Journal of the Science of Food and Agriculture. 90(4):664-668.

Interpretive Summary: Pistacia vera ‘Kerman’ is the predominant pistachio nut cultivar in the United States (California), the world’s second largest producer. Despite several reports on the essential oil (EO) content in the genus Pistacia, data on ‘Kerman’ is limited. The emission of volatile organic compounds (VOCs) can be closely related to the EO composition of a plant; thus, the EO content and (VOC) emissions of tree nut orchards are of current interest to researchers investigating insect pests and the potential role of EO and VOCs as semiochemicals. To establish a basis for the VOC output of pistachios, the EO content of fruits, peduncles, and leaves were analyzed. Evaulated plant parts contained limonene, a ubiquitous monoterpene, as the primary EO component, followed by terpinolene, a monoterpene. Peduncles, the stalks that support the inflorescence, were unique in containing alpha-thujene, also a monoterpene, albeit less common. The results were reproducible in different geographical locations, one collection site in the northern Central Valley and one in the southern Central Valley of California. In situ solid-phase microextraction (SPME) studies demonstrated the volatile emission was representative of the EO composition. This is the first report detailing the content and distribution of EO and the unique limonene-terpinolene dominant profile for this Pistacia vera cultivar.

Technical Abstract: Pistacia vera ‘Kerman’ is the predominant pistachio nut cultivar in the United States (California), the world’s second largest producer. Despite several reports on the essential oil (EO) content in the genus Pistacia, data on ‘Kerman’ is limited. The EO content and volatile organic compound (VOC) emissions of tree nut orchards are of current interest to researchers investigating insect pests and the potential role of EO and VOCs as semiochemicals. To establish a basis for the VOC output of pistachios, the EO content of fruits, peduncles, and leaves were analyzed. Evaluated plant parts contained limonene as the primary EO component, followed by terpinolene. Peduncles were unique in containing alpha-thujene. The results were reproducible between two different geographical locations. In situ SPME studies demonstrated the volatile emission was representative of the EO composition. This is the first report detailing the content and distribution of EO and the unique limonene-terpinolene dominant profile for this Pistacia vera cultivar.