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

Yvonne Gunning; Marianne Defernez; Andrew D. Watson; Niles Beadman; Ian J. Colquhoun; Gwenaelle Le Gall; Mark Philo; Hollie Garwood; David Williamson; Aaron P. Davis; E. Kate Kemsley

doi:10.1016/j.foodchem.2017.12.034

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

Yvonne Gunning, Marianne Defernez, Andrew D. Watson, Niles Beadman, Ian J. Colquhoun, Gwenaelle Le Gall, Mark Philo, Hollie Garwood, David Williamson, Aaron P. Davis, E. Kate Kemsley

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Abstract

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.

Original language	English
Pages (from-to)	52-60
Number of pages	9
Journal	Food Chemistry
Volume	248
Early online date	11 Dec 2017
DOIs	https://doi.org/10.1016/j.foodchem.2017.12.034
Publication status	Published - 15 May 2018

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

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Cite this

@article{3c14949a995c4af19a7e48f96bd83ec6,

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

abstract = "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.",

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",

author = "Yvonne Gunning and Marianne Defernez and Watson, {Andrew D.} and Niles Beadman and Colquhoun, {Ian J.} and {Le Gall}, Gwenaelle and Mark Philo and Hollie Garwood and David Williamson and Davis, {Aaron P.} and Kemsley, {E. Kate}",

year = "2018",

month = may,

day = "15",

doi = "10.1016/j.foodchem.2017.12.034",

language = "English",

volume = "248",

pages = "52--60",

journal = "Food Chemistry",

issn = "0308-8146",

publisher = "Elsevier",

}

TY - JOUR

T1 - 16-O-methylcafestol is present in ground roast Arabica coffees: Implications for authenticity testing

AU - Gunning, Yvonne

AU - Defernez, Marianne

AU - Watson, Andrew D.

AU - Beadman, Niles

AU - Colquhoun, Ian J.

AU - Le Gall, Gwenaelle

AU - Philo, Mark

AU - Garwood, Hollie

AU - Williamson, David

AU - Davis, Aaron P.

AU - Kemsley, E. Kate

PY - 2018/5/15

Y1 - 2018/5/15

N2 - 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.

AB - 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.

KW - NMR

KW - Spectroscopy

KW - Low-field

KW - Coffee

KW - Adulteration

KW - Species

KW - Arabica

KW - Robusta

KW - Authentication

KW - H-1-NMR SPECTROSCOPY

KW - GENETIC DIVERSITY

KW - DITERPENE ESTERS

KW - CANEPHORA

KW - ETHIOPIA

KW - MARKERS

KW - KAHWEOL

KW - L.

KW - QUANTIFICATION

KW - IDENTIFICATION

U2 - 10.1016/j.foodchem.2017.12.034

DO - 10.1016/j.foodchem.2017.12.034

M3 - Article

SN - 0308-8146

VL - 248

SP - 52

EP - 60

JO - Food Chemistry

JF - Food Chemistry

ER -