EN ISO 16634-1:2008

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Getreide, Hülsenfrüchte, gemahlene Getreideerzeugnisse, Ölsamen und Futtermittel - Bestimmung des Gehaltes an Gesamtstickstoff mit dem Verbrennungsverfahren nach Dumas und Berechnung des Gehaltes an Rohprotein (ISO 16634-1:2008)Produits alimentaires - Détermination de la teneur en azote total par combustion selon le principe Dumas et calcul de la teneur en protéines brutes - Partie 1 : Graines oléagineuses et aliments des animaux (ISO 16634-1:2008)Food products - Determination of the total nitrogen content by combustion according to the Dumas principle and calculation of the crude protein content - Part 1: Oilseeds and animal feeding stuffs (ISO 16634-1:2008)67.200.20OljniceOilseeds65.120KrmilaAnimal feeding stuffsICS:Ta slovenski standard je istoveten z:EN ISO 16634-1:2008SIST EN ISO 16634-1:2009en,fr,de01-januar-2009SIST EN ISO 16634-1:2009SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN ISO 16634-1November 2008ICS 65.120; 67.200; 67.050 English VersionFood products - Determination of the total nitrogen content bycombustion according to the Dumas principle and calculation ofthe crude protein content - Part 1: Oilseeds and animal feedingstuffs (ISO 16634-1:2008)Produits alimentaires - Détermination de la teneur en azotetotal par combustion selon le principe Dumas et calcul de lateneur en protéines brutes - Partie 1: Graines oléagineuseset aliments des animaux (ISO 16634-1:2008)Lebensmittelerzeugnisse - Bestimmung des Gehaltes anGesamtstickstoff mit dem Verbrennungsverfahren nachDumas und Berechnung des Gehaltes an Rohprotein - Teil1: Ölsaaten und Futtermittel (ISO 16634-1:2008)This European Standard was approved by CEN on 1 November 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 16634-1:2008: ESIST EN ISO 16634-1:2009

Reference numberISO 16634-1:2008(E)© ISO 2008
INTERNATIONAL STANDARD ISO16634-1First edition2008-11-01Food products — Determination of the total nitrogen content by combustion according to the Dumas principle and calculation of the crude protein content — Part 1: Oilseeds and animal feeding stuffs Produits alimentaires — Détermination de la teneur en azote total par combustion selon le principe Dumas et calcul de la teneur en protéines brutes — Partie 1: Graines oléagineuses et aliments des animaux
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ii © ISO 2008 – All rights reserved
ISO 16634-1:2008(E) © ISO 2008 – All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.1 4 Principle.2 5 Reagents.2 6 Apparatus.3 7 Sampling.4 8 Preparation of test sample.4 9 Procedure.4 9.1 General.4 9.2 Test portion.4 9.3 Control of oxygen demand.5 9.4 Calibration.5 9.5 Determination.5 9.6 Detection and integration.6 10 Calculation and expression of results.6 10.1 Calculation.6 10.1.1 Nitrogen content.6 10.1.2 Crude protein content.6 10.2 Expression of results.7 11 Precision.7 11.1 Interlaboratory tests.7 11.2 Repeatability.7 11.3 Reproducibility.7 12 Test report.7 Annex A (informative)
Flowchart for the basic design of a Dumas apparatus.8 Annex B (informative)
Schemes of suitable types of Dumas apparatus.9 Annex C (informative)
Equipment calibration.12 Annex D (informative)
Examples of factors for converting nitrogen content to protein content .14 Annex E (informative)
Result of collaborative studies.15 Annex F (informative)
Relationship between Dumas nitrogen and Kjeldahl nitrogen.24 Bibliography.28
ISO 16634-1:2008(E) iv © ISO 2008 – All rights reserved 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 a subject for which a technical committee has been established has the right to be represented 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 16634-1 was prepared by Technical Committee ISO/TC 34, Food products. ISO 16634 consists of the following parts, under the general title Food products — Determination of the total nitrogen content by combustion according to the Dumas principle and calculation of the crude protein content: ⎯ Part 1: Oilseeds and animal feeding stuffs A part 2 on cereals, pulses and milled cereal products is in preparation.
ISO 16634-1:2008(E) © ISO 2008 – All rights reserved vIntroduction For a long time the Kjeldahl method has been the most frequently used method for the determination of protein content of food products. However, in recent years, the Kjeldahl method has increasingly been replaced by the Dumas method, which is faster and does not use dangerous chemicals. Although the principles of the two methods are different, both measure the nitrogen content of the product. Nitrogen can be converted into protein content by using an appropriate factor. The value of this factor varies with the relative amounts of different proteins and their amino-acid composition in the given product. Neither the Dumas nor the Kjeldahl method distinguishes between protein and non-protein nitrogen. In most cases, results obtained by the Dumas method are slightly higher than those of the Kjeldahl method. This is due to the fact that the Dumas method measures almost all of the non-protein nitrogen, whereas the Kjeldahl method measures only a part of it. Taking into consideration that the calculated protein content of a product by both methods only approximates the true value, it is a matter of discretion which one is accepted. The most appropriate solution should be the use of a second factor f
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