16-O-methylcafestol is present in ground roast Arabica coffees: Implications for authenticity testing

Gunning, Yvonne, Defernez, Marianne, Watson, Andrew D., Beadman, Niles, Colquhoun, Ian J., Le Gall, Gwenaelle ORCID: https://orcid.org/0000-0002-1379-2196, Philo, Mark, Garwood, Hollie, Williamson, David, Davis, Aaron P. and Kemsley, E. Kate ORCID: https://orcid.org/0000-0003-0669-3883 (2018) 16-O-methylcafestol is present in ground roast Arabica coffees: Implications for authenticity testing. Food Chemistry, 248. pp. 52-60. ISSN 0308-8146

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High-field and low-field proton NMR spectroscopy were used to analyse lipophilic extracts from ground roast coffees. Using a sample preparation method that produced concentrated extracts, a small marker peak at 3.16 ppm was observed in 30 Arabica coffees of assured origin. This signal has previously been believed absent from Arabicas, and has been used as a marker for detecting adulteration with robusta. Via 2D 600 MHz NMR and LC-MS, 16-O-methylcafestol and 16-O-methylkahweol were detected for the first time in Arabica roast coffee and shown to be responsible for the marker peak. Using low-field NMR, robusta in Arabica could be detected at levels of the order of 1-2% w/w. A surveillance study of retail purchased "100% Arabica" coffees found that 6 out of 60 samples displayed the 3.16 ppm marker signal to a degree commensurate with adulteration at levels of 3-30% w/w.

Item Type: Article
Uncontrolled Keywords: nmr,spectroscopy,low-field,coffee,adulteration,species,arabica,robusta,authentication,h-1-nmr spectroscopy,genetic diversity,diterpene esters,canephora,ethiopia,markers,kahweol,l.,quantification,identification
Faculty \ School: Faculty of Science > School of Chemistry
UEA Research Groups: Faculty of Medicine and Health Sciences > Research Centres > Lifespan Health
Depositing User: LivePure Connector
Date Deposited: 20 Jul 2018 11:30
Last Modified: 19 Oct 2023 02:14
URI: https://ueaeprints.uea.ac.uk/id/eprint/67696
DOI: 10.1016/j.foodchem.2017.12.034

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