1、BS EN ISO 8968-4:2016Milk and milk products Determination of nitrogencontentPart 4: Determination of protein and non-protein nitrogen content and true protein content calculation (Reference method) (ISO 8968-4:2016)BS EN ISO 8968-4:2016Incorporating corrigendum February 2017BSI Standards Publication
2、WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN ISO 8968-4:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO 8968-4:2016. It supersedes BS EN ISO 8968-4:2002 and BS EN ISO 8968-5:2002 which are withdrawn.The UK participation in its preparati
3、on was entrusted to Technical Committee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible f
4、or its correct application. The British Standards Institution 2017. Published by BSI Standards Limited 2017ISBN 978 0 580 97520 2ICS 67.100.10Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Poli
5、cy and Strategy Committee on 30 April 2016.Amendments/corrigenda issued since publicationDate Text affected28 February 2017 Implementation of CEN Correction Notice 4 May 2016: supersession details correctedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8968-4 April 2016 ICS 67.100.10 Super
6、sedes EN ISO 8968-4:2001, EN ISO 8968-5:2001English 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 - Dterminatio
7、n de la teneur en azote - Partie 4: Dtermination de la teneur en azote protique et non protique et calcul de la teneur en protines vraies (Mthode de rfrence) (ISO 8968-4:2016) Milch und Milcherzeugnisse - Bestimmung des Stickstoffgehaltes - Teil 4: Bestimmung des Proteinstickstoff-Gehaltes und des N
8、ichtproteinstickstoff-Gehaltes und Berechnung des tatschlichen 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 E
9、uropean 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 vers
10、ions (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,
11、 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, S
12、witzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR 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 worldwide for CEN nat
13、ional Members. Ref. No. EN ISO 8968-4:2016 EBS EN ISO 8968-4:2016EN ISO 8968-4:2016 (E) 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
14、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
15、 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. According to the CEN-CENEL
16、EC 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, Ice
17、land, 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 modific
18、ation. BS EN ISO 8968-4:2016ISO 8968-4:2016(E)IDF 20-4:2016(E)Forewords .v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 14.1 Indirect protein nitrogen . 14.2 Direct protein nitrogen 25 Reagents 25.1 General . 25.2 Trichloroacetic acid (CCl3COOH) solution 25.3 Hydrochloric
19、 acid standard volumetric solution . 26 Apparatus . 27 Sampling 38 Preparation of test sample . 39 Procedure Direct protein nitrogen approach . 39.1 Test portion 39.2 Determination . 39.2.1 Precipitation and filtration . 39.2.2 Preparation of the precipitate 49.2.3 Digestion and distillation . 49.2.
20、4 Titration. 49.3 Blank test . 49.4 Calculation and expression of results 49.4.1 Calculation of protein nitrogen content . 49.4.2 Expression of results 59.4.3 Calculation of true protein content 59.4.4 Expression of the true protein content results 510 Procedure Indirect protein nitrogen approach 61
21、0.1 Nitrogen determination 610.2 Non-protein nitrogen determination . 610.2.1 Test portion 610.2.2 Precipitation and filtration . 610.2.3 Preparation of the filtrate. 610.2.4 Digestion and distillation . 610.2.5 Titration. 610.3 Blank test . 610.4 Calculation and expression of results 710.4.1 Calcul
22、ation of non-protein nitrogen content . 710.4.2 Calculation of protein nitrogen content . 710.4.3 Expression of results 810.4.4 Calculation of true protein content 810.4.5 Expression of the true protein content results 811 Precision . 811.1 Interlaboratory test. 811.2 Repeatability . 811.3 Reproduci
23、bility . 812 Test report . 9Annex A (informative) Results of a collaborative study Estimation of precision data of direct and indirect methods for the true protein determination .10 ISO and IDF 2016 All rights reserved iiiContents PageEN ISO 8968-4:2016 (E) 3 European forew rd This document (EN ISO
24、8968-4:2016) has been prepared by Technical Committee ISO/TC 34 “Food products“ in collaboration wi h 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 sta
25、ndard, 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 thi document may be the subject of patent rights
26、. CEN and/or CENELEC shall not be held responsible for identifying an 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 cou tries are bound to impleme
27、nt 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, S
28、lovakia, 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. BS EN ISO 8968-4:2016EN ISO 8968-4:2016 (E) 3 European foreword This document (EN ISO 8968-4:2016) has
29、 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
30、 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 CE
31、NELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 8968-4:2001. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, B
32、elgium, 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, Swi
33、tzerland, 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. BS EN ISO 8968-4:2016ISO 8968-4:2016(E)IDF 20-4:2016(E)Forewords .v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principl
34、e 14.1 Indirect protein nitrogen . 14.2 Direct protein nitrogen 25 Reagents 25.1 General . 25.2 Trichloroacetic acid (CCl3COOH) solution 25.3 Hydrochloric acid standard volumetric solution . 26 Apparatus . 27 Sampling 38 Preparation of test sample . 39 Procedure Direct protein nitrogen approach . 39
35、.1 Test portion 39.2 Determination . 39.2.1 Precipitation and filtration . 39.2.2 Preparation of the precipitate 49.2.3 Digestion and distillation . 49.2.4 Titration. 49.3 Blank test . 49.4 Calculation and expression of results 49.4.1 Calculation of protein nitrogen content . 49.4.2 Expression of re
36、sults 59.4.3 Calculation of true protein content 59.4.4 Expression of the true protein content results 510 Procedure Indirect protein nitrogen approach 610.1 Nitrogen determination 610.2 Non-protein nitrogen determination . 610.2.1 Test portion 610.2.2 Precipitation and filtration . 610.2.3 Preparat
37、ion of the filtrate. 610.2.4 Digestion and distillation . 610.2.5 Titration. 610.3 Blank test . 610.4 Calculation and expression of results 710.4.1 Calculation of non-protein nitrogen content . 710.4.2 Calculation of protein nitrogen content . 710.4.3 Expression of results 810.4.4 Calculation of tru
38、e protein content 810.4.5 Expression of the true protein content results 811 Precision . 811.1 Interlaboratory test. 811.2 Repeatability . 811.3 Reproducibility . 812 Test report . 9Annex A (informative) Results of a collaborative study Estimation of precision data of direct and indirect methods for
39、 the true protein determination .10 ISO and IDF 2016 All rights reserved iiiContents PageBS EN ISO 8968-4:2016ISO 8968-4:2016(E)IDF 20-4:2016(E)Bibliography .11iv ISO and IDF 2016 All rights reservedBS EN ISO 8968-4:2016ISO 8968-4:2016(E)ForewordsISO (the International Organization for Standardizati
40、on) 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 a subject for which a technical committee has been established has the right to be re
41、presented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to de
42、velop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the I
43、SO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during
44、 the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meanin
45、g of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 34, Fo
46、od products, Subcommittee SC 5, Milk and milk products and the International Dairy Federation (IDF). It is being published jointly by ISO and IDF.This second edition of ISO 8968-4|IDF 20-4 cancels and replaces ISO 8968-4|IDF 20-4:2001 and ISO 8968-5|IDF 20-5:2001, which have been technically revised
47、.ISO 8968|IDF 20 consists of the following parts, under the general title Milk and milk products Determination of nitrogen content: Part 1: Kjeldahl principle and crude protein calculation Part 3: Block-digestion method (Semi-micro rapid routine method)1) Part 4: Determination of protein and non-pro
48、tein nitrogen content and true protein content calculation (Reference method)1) It is intended that upon revision, the main element of the title of ISO 8968-3|IDF 20-3 (i.e. “Milk”) will be alignedwith the main element of the titles of ISO 8968-1|IDF 20-1 and ISO 8968-4|IDF 20-4.IDF 20-4:2016(E) ISO
49、 and IDF 2016 All rights reserved vBS EN ISO 8968-4:2016ISO 8968-4:2016(E)IDF 20-4:2016(E)Bibliography .11iv ISO and IDF 2016 All rights reservedBS EN ISO 8968-4:2016ISO 8968-4:2016(E)ForewordsISO (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 a subject for which a technical committee has been established has the right
