Volatile profiling in Rhus coriaria fruit (sumac) from three different geographical origins and upon roasting as analyzed via solid-phase microextraction

Mohamed A Farag; Nesrin M Fayek; Ibrahim Abou Reidah

doi:10.7717/peerj.5121

Volatile profiling in Rhus coriaria fruit (sumac) from three different geographical origins and upon roasting as analyzed via solid-phase microextraction

PeerJ. 2018 Jul 4:6:e5121. doi: 10.7717/peerj.5121. eCollection 2018.

Authors

Mohamed A Farag^{1

2}, Nesrin M Fayek¹, Ibrahim Abou Reidah³

Affiliations

¹ Pharmacognosy Department, College of Pharmacy, Cairo University, Cairo, Egypt.
² Department of Chemistry, American University in Cairo, New Cairo, Egypt.
³ Department of Chemistry, An-Najah National University, Nablus, Palestine.

Abstract

Rhus coriaria (sumac) is a fruit grown worldwide for its culinary use as a flavoring agent and for its health benefits. Despite several studies on R. coriaria non-volatile metabolites, much less is recognized concerning volatile composition within that genus. In an effort to expand on flavor profile sumac and its food products, we report on volatile profiling from three accessions of different origins including Palestine, Jordan and Egypt in addition to its cold tea and post roasting via headspace solid-phase microextraction (SPME). Under optimized conditions, 74 volatile components were identified belonging to alcohols, aromatics, esters, ethers, furan/aldehyde, hydrocarbons, ketones, monoterpenes, oxides and sesquiterpene hydrocarbons. Major identified components included α-pinene, naphthalene and o-cymene in Palestinian, Jordanian and Egyptian sumac, respectively. Whereas sesquiterpenes amounted for the major volatile class in fresh R. coriaria at ca. 40-58%, furan/aldehydes were the predominant classes in roasted fruits (58%). Volatile abundance data was further subjected to multivariate data analyses revealing furfural and nonanal enrichment in roasted compared to fresh fruits and their cold tea preparation. Seeds exhibited no aroma components which justified their removal in R. coriaria prior to its use as a food flavor. Such knowledge is expected to be the key for understanding the olfactory and taste properties of R. coriaria and its several food products.

Keywords: Anacardiaceae; Principal component analysis; Rhus coriaria; Roasting; Solid phase microextraction (SPME).

Grants and funding

Mohamed A. Farag was supported by Jesour grant number 30 from the Academy of Scientific Research & Technology (ASRT), Egypt and the American University of Cairo Research Support Grant (RSG1-18). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.