EN ISO 17678:2019
(Main)Milk and milk products - Determination of milk fat purity by gas chromatographic analysis of triglycerides (ISO 17678:2019)
Milk and milk products - Determination of milk fat purity by gas chromatographic analysis of triglycerides (ISO 17678:2019)
This document specifies a reference method for the determination of milk fat purity using gas chromatographic analysis of triglycerides. The method utilizes the differences in triglyceride fingerprint of milk fat from the individual triglyceride fingerprints of other fats and oils to determine samples which are outside the range normally observed for milk fat. This is achieved by using the defined triglyceride formulae based on the normalized weighted sum of individual triglyceride peaks which are sensitive to the integrity of the milk[6][7]. The integrity of the milk fat can be determined by comparing the result of these formulae with those previously observed for a range of pure milk fat samples[12]. Both vegetable fats and animal fats such as beef tallow and lard can be detected.
The method is applicable to bulk milk, or products made thereof, irrespective of the variation in common feeding practices, breed or lactation conditions. In particular, the method is applicable to fat extracted from milk products purporting to contain pure milk fat with unchanged composition, such as butter, cream, milk and milk powder.
Because a false-positive result can occur, the method does not apply to milk fat related to these circumstances:
a) obtained from bovine milk other than cow's milk;
b) obtained from single cows;
c) obtained from cows whose diet contained a particularly high proportion of vegetable oils such as rapeseed, cotton or palm oil, etc.;
d) obtained from cows suffering from serious underfeeding (strong energy deficit);
e) obtained from colostrum;
f) subjected to technological treatment such as removal of cholesterol or fractionation;
g) obtained from skim milk, buttermilk or whey;
h) obtained from cheeses showing increased lipolysis;
i) extracted using the Gerber, Weibull?Berntrop or Schmid?Bondzynski?Ratzlaff methods, or that has been isolated using detergents (e.g. the Bureau of Dairy Industries method).
With the extraction methods specified in i), substantial quantities of partial glycerides or phospholipids can pass into the fat phase.
NOTE 1 In nature, butyric (n-butanoic) acid (C4) occurs exclusively in milk fat and enables quantitative estimations of low to moderate amounts of milk fat in vegetable and animal fats to be made. Due to the large variation of C4, for which the approximate content ranges from 3,1 % fat mass fraction to 3,8 % fat mass fraction, it is difficult to provide qualitative and quantitative information for foreign fat to pure milk fat ratios of up to 20 % mass fraction[11].
NOTE 2 In practice, quantitative results cannot be derived from the sterol content of vegetable fats, because they depend on production and processing conditions. Furthermore, the qualitative determination of foreign fat using sterols is ambiguous.
NOTE 3 Due to special feeding practices such as those related to c) and d), false-positive results have sometimes been reported for milk from certain Asian regions[15]. Moreover, grass-only diets such as mountain and, in particular, highland pasture feeding sometimes cause false-positive results, which can be substantiated by a content of conjugated linoleic acid (C18:2 c9t11) of ≥ 1,3 % fatty acid mass fraction[16][17]. Nevertheless, results conforming to the criteria of milk fat purity specified in this document are accepted, even if samples were undoubtedly produced under conditions reported in this note, including those described in h).
NOTE 4 In ca
Milch und Milcherzeugnisse - Bestimmung der Reinheit des Milchfetts durch gaschromatographische Triglyceridanalyse (Referenzverfahren) (ISO 17678:2019)
Dieses Dokument legt ein Referenzverfahren zur Bestimmung der Reinheit des Milchfetts durch gaschro¬mato¬graphische Triglyceridanalyse fest. Bei diesem Verfahren werden die Unterschiede zwischen dem Triglycerid Fingerprint von Milchfett und den individuellen Triglycerid Fingerprints anderer Fette und Öle zur Bestimmung von Proben analysiert, die außerhalb des bei Milchfett üblicherweise festgestellten Bereichs liegen. Dies wird anhand von festgelegten Triglycerid-gleichungen erreicht, die auf der normalisierten gewichteten Summe der einzelnen Triglycerid¬spitzen beruht, die auf die Integrität der Milch [6] [7] reagieren. Die Integrität des Milchfetts kann durch Vergleiche der Ergebnisse dieser Gleichungen mit den zuvor bei einer Reihe reiner Milchfettproben [12] beobachteten Ergebnissen bestimmt werden. Es können sowohl pflanzliche als auch tierische Fette wie Rindertalg und Schweinefett nachgewiesen werden.
Grundsätzlich gilt das Verfahren für Sammelmilch oder daraus hergestellte Produkte, unabhängig von Abweichungen bei den allgemeinen Fütterungs , Zucht oder Laktationsbedingungen. Insbesondere ist das Verfahren auf Fett anwendbar, das aus Milchprodukten extrahiert wurde, die reines Milchfett in unver¬änderter Zusammensetzung enthalten sollen, wie z. B. Butter, Sahne, Milch und Milchpulver.
Jedoch kann in den nachstehend erwähnten Fällen ein falsch positives Ergebnis ermittelt werden. Deshalb ist das Verfahren nicht anwendbar auf Milchfett, das:
a) aus anderer Milch als Kuhmilch gewonnen wurde;
b) von einzelnen Kühen gewonnen wurde;
c) von Kühen gewonnen wurde, deren Futter einen besonders hohen Pflanzenölanteil aufwies, wie Raps-, Baumwollsamen oder Palmöl usw.;
d) von Kühen gewonnen wurde, die an erheblicher Unterernährung leiden (starkes Energiedefizit);
e) aus Kolostrum (Vormilch) gewonnen wurde;
f) einer technologischen Behandlung unterzogen wurde, wie z. B. dem Entfernen von Cholesterol oder einer Fraktionierung;
g) aus Magermilch, Buttermilch oder Molke gewonnen wurde;
h) aus Käse mit gesteigerter Lipolyse gewonnen wurde;
i) mit Verfahren nach Gerber, Weibull Berntrop oder Schmid Bondzynski Ratzlaff extrahiert oder mittels Detergenzien isoliert wurde [z. B. mit dem Bureau of Dairy Industries (BDI) Verfahren].
Mit den in Punkt i) festgelegten Extraktionsverfahren können beträchtliche Mengen von Partialglyceriden oder Phospholipiden in die Fettphase übertreten.
Lait et produits laitiers - Détermination de la pureté des matières grasses laitières par analyse chromatographique en phase gazeuse des triglycérides (ISO 17678:2019)
Le présent document spécifie une méthode de référence pour la détermination de la pureté des matières grasses laitières par analyse chromatographique en phase gazeuse des triglycérides. La méthode utilise les différences d'empreintes des triglycérides présents dans les matières grasses laitières par rapport aux empreintes des triglycérides individuels des autres matières grasses et huiles pour déterminer des échantillons se situant en dehors de la plage normalement observée pour les matières grasses laitières. Cela est réalisé en utilisant les formules de triglycérides définies basées sur la somme pondérée normalisée des pics de triglycérides individuels, qui sont sensibles à l'intégrité du lait[6][7]. L'intégrité des matières grasses laitières peut être déterminée en comparant les résultats de ces formules à ceux précédemment observés pour une gamme d'échantillons de matières grasses laitières pures[12]. Il est possible de détecter des matières grasses d'origines végétale et animale telles que la graisse de bœuf et le saindoux.
La méthode s'applique au lait en vrac, ou aux produits laitiers dérivés, indépendamment de la variation des pratiques d'alimentation courantes et des conditions d'élevage ou de lactation. Elle s'applique en particulier aux matières grasses extraites de produits laitiers supposés contenir des matières grasses laitières pures, présentant une composition non modifiée, comme le beurre, la crème, le lait et le lait en poudre.
Un résultat faux positif pouvant être obtenu, la méthode n'est pas applicable à la matière grasse laitière liée aux circonstances listées ci-après:
a) issue de lait de bovin autre que le lait de vache;
b) issue de vaches individuelles;
c) issue de vaches dont l'alimentation contenait une proportion particulièrement élevée d'huiles végétales telles que l'huile de colza, l'huile de coton ou de palme, etc.;
d) issue de vaches souffrant d'une grave sous-alimentation (puissant déficit énergétique);
e) issue du colostrum;
f) soumise à un traitement technologique tel que l'élimination du cholestérol ou le fractionnement;
g) issue du lait écrémé, du lait battu (babeurre) ou du lactosérum;
h) issue de fromages présentant une lipolyse importante;
i) extraite selon les méthodes Gerber, Weibull?Berntrop ou Schmid?Bondzynski?Ratzlaff, ou isolée au moyen de détergents [par exemple méthode BDI (Bureau of Dairy Industries)].
Avec les méthodes d'extraction spécifiées en i), d'importantes quantités de glycérides ou phospholipides partiels peuvent passer dans la phase grasse.
NOTE 1 Dans la nature, l'acide butyrique (n-butanoïque) (C4) se trouve exclusivement dans les matières grasses laitières et permet d'effectuer des estimations quantitatives de petites et moyennes quantités de matières grasses laitières dans les graisses végétales et animales. En raison de la grande variation de C4, pour lequel la fraction massique est comprise approximativement entre 3,1 % et 3,8 % de la matière grasse, des informations qualitatives et quantitatives peuvent difficilement être fournies lorsque le rapport des matières grasses étrangères aux matières grasses laitières pures atteint jusqu'à 20 % en fraction massique[11].
NOTE 2 Dans la pratique, des résultats quantitatifs ne peuvent pas être déduits de la teneur en stérols des matières grasses végétales, étant donné que celles-ci sont fonction des conditions de production et de traitement. En outre, la détermination qualitative de matières grass
Mleko in mlečni proizvodi - Določanje čistosti mlečne maščobe s plinsko kromatografsko analizo trigliceridov (referenčna metoda) (ISO 17678:2019)
Ta dokument določa referenčno metodo za določanje čistosti mlečne maščobe z uporabo analize trigliceridov s plinsko kromatografijo. Pri tej metodi se uporabljajo razlike med identifikacijo trigliceridov v mlečni maščobi in identifikacijo posameznih trigliceridov v drugih masteh in oljih za določanje vzorcev, ki so zunaj razpona takih, ki so običajno opazovani pri mlečni maščobi. To se doseže z uporabo določenih formul za trigliceride, ki temeljijo na normalizirani ponderirani vsoti posameznih najvišjih vrednosti trigliceridov, ki so občutljivi na integriteto mleka [6][7]. Integriteto mlečne maščobe je mogoče ugotoviti s primerjavo rezultata teh formul s predhodno opazovanimi za različne vzorce čiste mlečne maščobe [12]. Mogoče je odkriti tako rastlinske kot tudi živalske maščobe, kot sta goveji loj in mast. Ta metoda se uporablja za velike količine mleka ali iz njega narejene izdelke, ne glede na razlike pri običajnih praksah krmljenja, pasmah ali laktacijskih pogojih. Metoda se uporablja zlasti za maščobo, ekstrahirano iz mlečnih izdelkov, ki domnevno vsebujejo čisto mlečno maščobo z nespremenjeno sestavo, na primer maslo, smetana, mleko in mleko v prahu.
Zaradi možnosti lažnega pozitivnega rezultata se metoda ne uporablja za mlečno maščobo, kadar
je ta:
a) pridobljena iz drugega mleka kot kravjega;
b) pridobljena od posameznih krav;
c) pridobljena od krav, ki so imele v prehrani še posebej visok delež rastlinskih olj, na primer
repično, bombažno ali palmovo olje ipd.;
d) pridobljena od resno podhranjenih krav (velik primanjkljaj energije);
e) pridobljena iz mleziva;
f) tehnološko obdelana, na primer z odstranitvijo holesterola ali frakcioniranjem;
g) pridobljena iz posnetega mleka, pinjenca ali sirotke;
h) pridobljena iz sirov, ki izkazujejo povečano lipolizo;
i) ekstrahirana z metodami po Gerberju, Weibull–Berntropu ali Schmid–Bondzynski–Ratzlaffu ali izolirana z detergenti (npr. z metodo ameriškega urada za mlečno industrijo).
Pri metodi ekstrakcije, določeni pod točko i), lahko znatne količine delnih gliceridov ali fosfolipidov preidejo v maščobno fazo.
OPOMBA 1: V naravi se butirična (n-butanojska) kislina (C4) pojavlja izključno v mlečni maščobi in omogoča kvantitativno ocenjevanje nizkih do srednjih količin mlečne maščobe v rastlinskih in živalskih maščobah. Zaradi velikih razlik pri C4, pri čemer je približna vsebnost med 3,1 % masnega deleža maščobe in 3,8 % masnega deleža maščobe, je težko podati kvalitativne in kvantitativne informacije za razmerje med tujo maščobo in čisto mlečno maščobo z do 20 % masnega deleža [11].
OPOMBA 2: Kvantitativnih rezultatov v praksi ni mogoče pridobiti iz vsebnosti sterolov v rastlinskih maščobah, ker so odvisni od proizvodnje in pogojev predelave. Poleg tega je kvalitativno določevanje tuje maščobe z uporabo sterolov dvoumno.
OPOMBA 3: Zaradi posebnih praks krmljenja, podobnih tistim v zvezi s točkama c) in d),
včasih poročajo o lažnih pozitivnih rezultatih iz določenih regij v Aziji [15]. Poleg tega lahko krmljenje izključno s travo, na primer pri pašnji na planinskih pašnikih in zlasti na visokogorskih pašnikih, povzroči lažne pozitivne rezultate, ki jih je mogoče potrditi s konjugirano linolno kislino (C18:2 c9t11) z vsebnostjo ≥ 1,3 % masnega deleža maščobnih kislin [16][17]. Kljub temu so rezultati sprejemljivi, če so skladni s kriteriji čistosti mlečne maščobe, ki so določeni v tem dokumentu, čeprav so bili vzorci nedvomno odvzeti v pogojih, poročanih v teh opombi, vključno z opisanimi pod točko h).
OPOMBA 4: V primerih, ko pozitiven rezultat domnevno nastane zaradi okoliščin, povezanih s točkama c) in d), je za potrditev izsledkov dovoljeno uporabiti drugo analitično metodo, na primer analizo maščobnih kislin ali analizo sterolov. Zaradi podobnih ali povečanih omejitev (npr. opisanih v OPOMBI 1 in OPOMBI 2) z drugo metodo pridobljen negativni rezultat ni primeren za nasprotno potrditev čistosti mlečne maščobe.
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2019
Nadomešča:
SIST EN ISO 17678:2010
Mleko in mlečni proizvodi - Določanje čistosti mlečne maščobe s plinsko
kromatografsko analizo trigliceridov (referenčna metoda) (ISO 17678:2019)
Milk and milk products - Determination of milk fat purity by gas chromatographic analysis
of triglycerides (ISO 17678:2019)
Milch und Milcherzeugnisse - Bestimmung der Reinheit des Milchfetts durch
gaschromatographische Triglyceridanalyse (Referenzverfahren) (ISO 17678:2019)
Lait et produits laitiers - Détermination de la pureté des matières grasses laitières par
analyse chromatographique en phase gazeuse des triglycérides (ISO 17678:2019)
Ta slovenski standard je istoveten z: EN ISO 17678:2019
ICS:
67.100.10 Mleko in predelani mlečni Milk and processed milk
proizvodi products
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 17678
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 67.100.10 Supersedes EN ISO 17678:2010
English Version
Milk and milk products - Determination of milk fat purity
by gas chromatographic analysis of triglycerides (ISO
17678:2019)
Lait et produits laitiers - Détermination de la pureté Milch und Milcherzeugnisse - Bestimmung der Reinheit
des matières grasses laitières par analyse des Milchfetts durch gaschromatographische
chromatographique en phase gazeuse des triglycérides Triglyceridanalyse (Referenzverfahren) (ISO
(ISO 17678:2019) 17678:2019)
This European Standard was approved by CEN on 6 March 2018.
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,
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United Kingdom.
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COMITÉ EUROPÉEN DE NORMALISATION
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CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17678:2019 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 17678:2019) has been prepared by Technical Committee ISO/TC 34 "Food
products" in collaboration with Technical Committee CEN/TC 302 “Milk and milk products - Methods of
sampling and analysis” the secretariat of which is held by NEN.
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 December 2019, and conflicting national standards
shall be withdrawn at the latest by December 2019.
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.
This document supersedes EN ISO 17678:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 17678:2019 has been approved by CEN as EN ISO 17678:2019 without any modification.
INTERNATIONAL ISO
STANDARD 17678
IDF 202
Second edition
2019-06
Milk and milk products —
Determination of milk fat purity
by gas chromatographic analysis of
triglycerides
Lait et produits laitiers — Détermination de la pureté des matières
grasses laitières par analyse chromatographique en phase gazeuse
des triglycérides
Reference numbers
ISO 17678:2019(E)
IDF 202:2019(E)
©
ISO and IDF 2019
ISO 17678:2019(E)
IDF 202:2019(E)
© ISO and IDF 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
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ii © ISO and IDF 2019 – All rights reserved
ISO 17678:2019(E)
IDF 202:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Principle . 2
5 Reagents . 3
6 Apparatus . 3
7 Sampling . 4
8 Procedure. 5
8.1 Preparation of test samples . 5
8.1.1 General. 5
8.1.2 Isolation from butter or butteroil. 5
8.1.3 Extraction according to the Röse–Gottlieb gravimetric method . 5
8.1.4 Extraction from milk using silica gel columns . 5
8.1.5 Extraction from cheese . 6
8.2 Preparation of fat sample solution . 6
8.3 Chromatographic triglyceride determination . 6
8.3.1 Baseline drift . 6
8.3.2 Injection technique . 6
8.3.3 Calibration . 6
8.3.4 Chromatographic conditions . 7
9 Integration, evaluation and control of the analytical performance .8
10 Calculation and expression of results .10
10.1 Triglyceride composition .10
10.1.1 Calculation .10
10.1.2 Expression of test results .10
10.2 S-values .11
10.2.1 Calculation .11
10.2.2 Expression of test results .11
10.3 Detection of foreign fat.11
11 Precision .12
11.1 Interlaboratory test.12
11.2 Repeatability .12
11.3 Reproducibility .12
12 Test report .13
Annex A (normative) Preparation of the packed column .14
Annex B (informative) Quantification of the foreign fat content .18
Annex C (informative) Uncertainty of measurement .20
Annex D (informative) Interlaboratory test .21
Bibliography .23
ISO 17678:2019(E)
IDF 202:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national
standards bodies (ISO member bodies). The work of preparing International Standards is normally
carried out through ISO technical committees. Each member body interested in
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