EN ISO 8968-4:2016

Milk and milk products - Determination of nitrogen content - Part 4: Determination of protein and non-protein nitrogen content and true protein content calculation (Reference method) (ISO 8968-4:2016)

ISO 8968-4|IDF 20-4:2016 specifies a method for the direct and indirect determination of the protein nitrogen content of liquid, whole or skimmed milk.

Milch und Milcherzeugnisse - Bestimmung des Stickstoffgehaltes - Teil 4: Bestimmung des Proteinstickstoff-Gehaltes und des Nichtproteinstickstoff-Gehaltes und Berechnung des tatsächlichen Proteingehaltes (Referenzverfahren) (ISO 8968-4:2016)

Dieser Teil von ISO 8968|IDF 20 legt ein Verfahren zur direkten und indirekten Bestimmung des Proteinstickstoff-Gehaltes von flüssiger, unbehandelter oder entrahmter Milch fest.

Lait et produits laitiers - Détermination de la teneur en azote - Partie 4: Détermination de la teneur en azote protéique et non protéique et calcul de la teneur en protéines vraies (Méthode de référence) (ISO 8968-4:2016)

ISO 8968-4|FIL 20-4:2016 spécifie une méthode pour la détermination directe et indirecte de la teneur en azote protéique du lait liquide, entier ou écrémé.

Mleko in mlečni proizvodi - Določevanje vsebnosti dušika - 4. del: Določevanje vsebnosti beljakovinskega in nebeljakovinskega dušika ter izračun dejanske vsebnosti beljakovin (referenčna metoda) (ISO 8968-4:2016)

Ta del standarda ISO 8968|IDF 20 določa metodo za neposredno in posredno določevanje beljakovinskega dušika v tekočem, polnomastnem in posnetem mleku.

General Information

• Status: Published
• Publication Date: 19-Apr-2016
• Withdrawal Date: 30-Oct-2016
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Drafting Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 20-Apr-2016
• Completion Date: 20-Apr-2016
• Ref Project: SIST EN ISO 8968-4:2016 - Milk and milk products - Determination of nitrogen content - Part 4: Determination of protein and non-protein nitrogen content and true protein content calculation (Reference method) (ISO 8968-4:2016)

Relations

• Replaces: EN ISO 8968-5:2001 - Milk - Determination of nitrogen content - Part 5: Determination of protein-nitrogen content (ISO 8968-5:2001)
• Effective Date: 11-May-2016
• Replaces: EN ISO 8968-4:2001 - Milk - Determination of nitrogen content - Part 4: Determination of non-protein nitrogen content (ISO 8968-4:2001)
• Effective Date: 27-Apr-2016
• Replaces: EN ISO 8968-4:2001/AC:2012 - Milk - Determination of nitrogen content - Part 4: Determination of non-protein-nitrogen content - Technical Corrigendum 1 (ISO 8968-4:2001/Cor 1:2011)
• Effective Date: 27-Apr-2016

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2016
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SIST EN ISO 8968-4:2002
SIST EN ISO 8968-4:2002/AC:2012
SIST EN ISO 8968-5:2002
0OHNRLQPOHþQLSURL]YRGL'RORþHYDQMHYVHEQRVWLGXãLNDGHO'RORþHYDQMH
YVHEQRVWLEHOMDNRYLQVNHJDLQQHEHOMDNRYLQVNHJDGXãLNDWHUL]UDþXQGHMDQVNH
YVHEQRVWLEHOMDNRYLQUHIHUHQþQDPHWRGD,62
Milk and milk products - Determination of nitrogen content - Part 4: Determination of
protein and non-protein nitrogen content and true protein content calculation (Reference
method) (ISO 8968-4:2016)
Milch und Milcherzeugnisse - Bestimmung des Stickstoffgehaltes - Teil 4: Bestimmung
des Proteinstickstoff-Gehaltes und des Nichtproteinstickstoff-Gehaltes und Berechnung
des tatsächlichen Proteingehaltes (Referenzverfahren) (ISO 8968-4:2016)
Lait et produits laitiers - Détermination de la teneur en azote - Partie 4: Détermination de
la teneur en azote protéique et non protéique et calcul de la teneur en protéines vraies
(Méthode de référence) (ISO 8968-4:2016)
Ta slovenski standard je istoveten z: EN ISO 8968-4:2016
ICS:
67.100.10 0OHNRLQSUHGHODQLPOHþQL Milk and processed milk
SURL]YRGL products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8968-4
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2016
EUROPÄISCHE NORM
ICS 67.100.10 Supersedes EN ISO 8968-4:2001, EN ISO 8968-5:2001
English Version
Milk and milk products - Determination of nitrogen
content - Part 4: Determination of protein and non-protein
nitrogen content and true protein content calculation
(Reference method) (ISO 8968-4:2016)
Lait et produits laitiers - Détermination de la teneur en Milch und Milcherzeugnisse - Bestimmung des
azote - Partie 4: Détermination de la teneur en azote Stickstoffgehaltes - Teil 4: Bestimmung des
protéique et non protéique et calcul de la teneur en Proteinstickstoff-Gehaltes und des
protéines vraies (Méthode de référence) (ISO 8968- Nichtproteinstickstoff-Gehaltes und Berechnung des
4:2016) tatsächlichen Proteingehaltes (Referenzverfahren)
(ISO 8968-4:2016)
This European Standard was approved by CEN on 19 March 2016.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8968-4:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8968-4:2016) has been prepared by Technical Committee ISO/TC 34 "Food
products" in collaboration with Technical Committee CEN/TC 278 “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 October 2016, and conflicting national standards shall
be withdrawn at the latest by October 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 8968-4:2001 and EN ISO 8968-5:2001.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 8968-4:2016 has been approved by CEN as EN ISO 8968-4:2016 without any
modification.
INTERNATIONAL ISO
STANDARD 8968-4
IDF
20-4
Second edition
2016-04-01
Milk and milk products —
Determination of nitrogen content —
Part 4:
Determination of protein and
non-protein nitrogen content and
true protein content calculation
(Reference method)
Lait et produits laitiers — Détermination de la teneur en azote —
Partie 4: Détermination de la teneur en azote protéique et non
protéique et calcul de la teneur en protéines vraies (Méthode de
référence)
Reference numbers
ISO 8968-4:2016(E)
IDF 20-4:2016(E)
©
ISO and IDF 2016
ISO 8968-4:2016(E)
IDF 20-4:2016(E)
© ISO and IDF 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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 below or ISO’s member body in the country of
the requester.
ISO copyright office International Dairy Federation
Ch. de Blandonnet 8 • CP 401 Silver Building • Bd Auguste Reyers 70/B • B-1030 Brussels
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone] Tel. + 32 2 325 67 40
Fax [phone] Fax + 32 2 325 67 41
[e-mail] [e-mail]
www.iso.org www.fil-idf.org
ii © ISO and IDF 2016 – All rights reserved

ISO 8968-4:2016(E)
IDF 20-4:2016(E)
Contents Page
Forewords .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
4.1 Indirect protein nitrogen . 1
4.2 Direct protein nitrogen . 2
5 Reagents . 2
5.1 General . 2
5.2 Trichloroacetic acid (CCl COOH) solution . 2
5.3 Hydrochloric acid standard volumetric solution . 2
6 Apparatus . 2
7 Sampling . 3
8 Preparation of test sample . 3
9 Procedure — Direct protein nitrogen approach . 3
9.1 Test portion . 3
9.2 Determination . 3
9.2.1 Precipitation and filtration . 3
9.2.2 Preparation of the precipitate . 4
9.2.3 Digestion and distillation . 4
9.2.4 Titration. 4
9.3 Blank test . 4
9.4 Calculation and expression of results. 4
9.4.1 Calculation of protein nitrogen content . 4
9.4.2 Expression of results . 5
9.4.3 Calculation of true protein content . 5
9.4.4 Expression of the true protein content results . 5
10 Procedure — Indirect protein nitrogen approach . 6
10.1 Nitrogen determination . 6
10.2 Non-protein nitrogen determination . . 6
10.2.1 Test portion . 6
10.2.2 Precipitation and filtration . 6
10.2.3 Preparation of the filtrate. 6
10.2.4 Digestion and distillation . 6
10.2.5 Titration. 6
10.3 Blank test . 6
10.4 Calculation and expression of results. 7
10.4.1 Calculation of non-protein nitrogen content . 7
10.4.2 Calculation of protein nitrogen content . 7
10.4.3 Expression of results .
...