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, Philo, Mark, Garwood, Hollie, Williamson, David, Davis, Aaron P. and Kemsley, E. Kate (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
Depositing User: LivePure Connector
Date Deposited: 20 Jul 2018 11:30
Last Modified: 15 Nov 2020 00:56
URI: https://ueaeprints.uea.ac.uk/id/eprint/67696
DOI: 10.1016/j.foodchem.2017.12.034

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