EN 17992:2024
(Main)Food authenticity - Determination of the sum of 16-O-Methylcafestol, 16-O-Methylkahweol and their derivatives in roasted coffee by ¹H-qNMR
Food authenticity - Determination of the sum of 16-O-Methylcafestol, 16-O-Methylkahweol and their derivatives in roasted coffee by ¹H-qNMR
This document specifies a method for the determination of soluble 16-O-Methylcafestol and 16-O-Methylkahweol content (the sum of free forms and derivatives, e.g. fatty acid esters, henceforth abbreviated as 16-OMD = “diterpenes”) in roasted coffee (beans or ground), using quantitative proton nuclear magnetic resonance spectroscopy (1H-qNMR).
If complying with the experimental parameters described below, this test procedure has been proven for the following mass fraction range:
w16-OMD: 20 mg/kg to 2 000 mg/kg.
The mass fraction range can be expanded by suitable changes of the experimental parameters, e.g. a different weighed portion of ground coffee or the accumulation of more NMR-transients.
Lebensmittelauthentizität - Bestimmung des Gehalts von 16-O-Methylcafestol, 16-O-Methylkahweol und deren Derivaten als Summenparameter in Röstkaffee mittels ¹H-qNMR
Dieses Dokument legt ein Verfahren zur Bestimmung des Gehalts an löslichem 16 O Methylcafestol und 16 O Methylkahweol (Summe der freien Formen und Derivate, z. B. Fettsäureester, im Folgenden abgekürzt als 16 OMD = „Diterpene“) in geröstetem Kaffee (Bohnen oder gemahlen) mittels quantitativer Protonen-nuklearmagnetischer Resonanzspektroskopie (1H qNMR) fest.
Bei Einhaltung der nachstehend beschriebenen Versuchsparameter hat sich dieses Prüfverfahren für den folgenden Bereich der Massenanteile bewährt:
w16-OMD: 20 mg/kg bis 2 000 mg/kg.
Der Bereich der Massenanteile kann durch geeignete Änderungen der Versuchsparameter erweitert werden, z. B. durch eine andere Einwaage des gemahlenen Kaffees oder die Akkumulation von mehr NMR Transienten.
Authenticité des aliments - Détermination par résonance magnétique nucléaire quantitative du proton (RMN-¹H) de la somme des teneurs en 16-O-méthylcafestol, 16-O-méthylkahwéol et leurs dérivés dans le café torréfié
Le présent document spécifie une méthode de détermination de la teneur en 16-O-méthylcafestol et 16 O-méthylkahwéol solubles (somme des formes libres et des dérivés, par exemple esters d’acides gras, désormais abrégé 16-OMD = « diterpènes ») du café torréfié (en grains ou moulu), par spectroscopie par résonance magnétique nucléaire quantitative du proton (qRMN-1H).
En respectant les paramètres expérimentaux décrits ci-dessous, ce mode opératoire d’essai a été validé pour la gamme de fractions massiques suivantes :
w16-OMD : 20 mg/kg à 2 000 mg/kg.
La gamme de fractions massiques peut être élargie en modifiant de façon adéquate les paramètres expérimentaux, par exemple une prise d’essai différente de café moulu ou l’accumulation de plusieurs transitions RMN.
Pristnost živil - Določanje vsote 16-O-metilkafestola, 16-O-metilkaveola in njunih derivatov v praženi kavi z metodo ¹H-qNMR
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2025
Pristnost živil - Določanje vsote 16-O-metilkafestola, 16-O-metilkaveola in njunih
derivatov v praženi kavi z metodo ¹H-qNMR
Food authenticity - Determination of the sum of 16-O-methylcafestol, 16-O-
Methylkahweol and their derivatives in roasted coffee by ¹H-qNMR
Lebensmittelauthentizität - Bestimmung des Gehalts von 16-O-Methylcafestol, 16-O-
Methylkahweol und deren Derivaten als Summenparameter in Röstkaffee mittels ¹H-
qNMR
Authenticité alimentaire du café - Détermination de la teneur en 16-O-méthylcafestol -
Méthode par NMR
Ta slovenski standard je istoveten z: EN 17992:2024
ICS:
67.140.20 Kava in kavni nadomestki Coffee and coffee substitutes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 17992
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2024
EUROPÄISCHE NORM
ICS 67.140.20
English Version
Food authenticity - Determination of the sum of 16-O-
Methylcafestol, 16-O-Methylkahweol and their derivatives
in roasted coffee by ¹H-qNMR
Authenticité des aliments - Détermination par Lebensmittelauthentizität - Bestimmung des Gehalts
résonance magnétique nucléaire quantitative du von 16-O-Methylcafestol, 16-O-Methylkahweol und
proton (RMN-¹H) de la somme des teneurs en 16-O- deren Derivaten als Summenparameter in Röstkaffee
méthylcafestol, 16-O-méthylkahwéol et leurs dérivés mittels ¹H-qNMR
dans le café torréfié
This European Standard was approved by CEN on 2 September 2024.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17992:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 8
5 Reagents . 9
6 Apparatus . 10
7 Measurement and test methods . 11
7.1 General. 11
7.2 Sampling . 11
7.3 Sample preparation . 11
7.3.1 General. 11
7.3.2 Sample preparation of coffee beans . 11
7.3.3 Sample preparation of ground coffee . 11
7.3.4 Extraction and preparation of the measuring solution . 12
7.4 NMR experiments . 12
7.4.1 General. 12
7.4.2 Fundamental criteria for the NMR Spectrum . 12
7.4.3 Valid exemplary measuring conditions/ parameters for the 1D experiment . 13
7.4.4 Acquisition parameters for the 1D experiment . 14
7.4.5 Processing parameters for the 1D experiment . 14
7.5 Quality control monitoring . 15
7.5.1 Checking the acquisition quality of the spectra . 15
7.5.2 Checking the qNMR calibration and sample preparation process . 15
7.6 Determination of the PULCON factor . 16
7.7 Calculation of the analyte mass fractions in coffee. 16
7.8 List of analytes and relevant parameters . 17
8 Accuracy . 18
8.1 Ring test / Interlaboratory comparison test . 18
8.2 Repeatability . 18
8.3 Reproducibility . 18
8.4 Limit of quantification (LOQ) . 18
9 Test report . 18
Annex A (informative) Summary of the statistical evaluation of the method validation study
“16-OMC in coffee” . 19
Annex B (informative) Common collaborative study of this NMR method and the HPLC
method (EN 18003:2024) . 23
Bibliography . 24
European foreword
This document (EN 17992:2024) has been prepared by Technical Committee CEN/TC 460 “Food
authenticity”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2025, and conflicting national standards shall be
withdrawn at the latest by May 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document was developed in response to standardization demand for an efficient and reliable test
method allowing the confirmation of coffee authenticity both for commercial quality control and for
official food control.
The coffee species with the greatest commercial importance are Coffea arabica and Coffea canephora var.
robusta, commonly known as “arabica” and “robusta”. Within these species, arabica coffees have a
significantly higher market value than robusta coffees. For roasted coffee samples the claim “100 %
arabica”, “pure arabica” can be authenticated by analysing the mass fraction of 16-O-Methylcafestol and
16-O-Methylkahweol and their derivatives (e.g. fatty acid esters). Whereas arabica coffees contain no
detectable or only very small amounts of these analytes (less than 20 mg/kg), the mass fractions in
1, [1]-[7]
robusta coffees are significantly higher in the approximate range of 800 to 2 500 mg/kg .
[8]
Metrologically, quantitative NMR (qNMR) is a proven primary method of measurement . This means
that the quantity determination by NMR is directly related to the definition of the unit of measurement
and/ or basic fundamental constants. Thus, the measurement process is physically fully understood and
a complete error budget and its physical causation can be described. NMR does not need substance
specific calibration.
Three approaches to qNMR are common and regularly used:
— use of an internal standard (adding an exact quantity of a reference substance to the sample);
— projection of a concentration-calibrated artificial signal into the sample’s spectrum (called ERETIC
[9]
method) ;
— calibration of the spectrometer’s response (under comparable acquisition conditions) with an
[10]
external standard of exactly known concentrations (called PULCON method or ERETIC2) .
This analysis method uses the PULCON method to quantify analytes with NMR.
These published values are quoted as an orientation only and not intended as strict threshold recommendations.
1 Scope
This document specifies a method for the determination of soluble 16-O-Methylcafestol and 16-O-
Methylkahweol content (the sum of free forms and derivatives, e.g. fatty acid esters, henceforth
abbreviated as 16-OMD = “diterpenes”) in roasted coffee (beans or ground), using quantitative proton
nuclear magnetic resonance spectroscopy ( H-qNMR).
If complying with the experimental parameters described below, this test procedure has been proven for
the following mass fraction range:
w : 20 mg/kg to 2 000 mg/kg.
16-OMD
The mass fraction range can be expanded by suitable changes of the experimental parameters, e.g. a
different weighed portion of ground coffee or the accumulation of more NMR-transients.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 1042, Laboratory glassware — One-mark volumetric flasks (ISO 1042)
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3509, Coffee and coffee products — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3509 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
16-OMD content
amount of 16-OMC and 16-OMK (both are 16-O-Methylditerpenes) and their derivatives in coffee
Note 1 to entry: It is extractable with chloroform, determined according to this test procedure and usually quoted
as a mass fraction w in mg/kg coffee, calculated as free 16-OMC.
Note 2 to entry: An additional fraction of the total 16-OMD content (ca. 25 %) can only be extracted by vigorous
chemical processing.
Note 3 to entry: Approximately a mass fraction of 90 % of the 16-OMD is represented by 16-O-Methylcafestol, and
16-O-Methylkahweol represent the remaining mass fraction of 10 % of the mixture.
Note 4 to entry: The relative error due to differences in molar weight is 0,6 %.
[1]
[SOURCE: bibliography ]
EN 17992
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