1、BS EN ISO2450:2008ICS 67.100.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDCream Determination of fatcontent Gravimetricmethod (Referencemethod) (ISO2450:2008)This British Standard was published under theauthority of the StandardsPolicy and StrategyCommittee
2、 on 31 January2009 BSI 2009ISBN 978 0 580 63535 9Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 2450:2008National forewordThis British Standard is the UK implementation of EN ISO 2450:2008. Itsupersedes BS EN ISO 2450:1999 which is withdrawn.The UK participation in its preparat
3、ion was entrusted to TechnicalCommittee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for
4、 its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 2450October 2008ICS 67.100.10 Supersedes EN ISO 2450:1999 English VersionCream - Determination of fat content - Gravimetric method(Reference
5、method) (ISO2450:2008)Crme - Dtermination de la teneur en matire grasse -Mthode gravimtrique (Mthode de rfrence) (ISO2450:2008)Sahne - Bestimmung des Fettgehaltes - GravimetrischesVerfahren (Referenzverfahren) (ISO 2450:2008)This European Standard was approved by CEN on 14 October 2008.CEN members a
6、re 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 t
7、he 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 s
8、tatus 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,
9、 Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwi
10、de for CEN national Members.Ref. No. EN ISO 2450:2008: EBS EN ISO 2450:2008EN ISO 2450:2008 (E) 3 Foreword This document (EN ISO 2450:2008) has been prepared by Technical Committee ISO/TC 34 “Agricultural food products“ in collaboration with Technical Committee CEN/TC 302 “Milk and milk products - M
11、ethods 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 April 2009, and conflicting national standards shall be withdrawn at the
12、latest by April 2009. 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 2450:1999. According to the CEN/
13、CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lu
14、xembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 2450:2008 has been approved by CEN as EN ISO 2450:2008 without any modification. BS EN ISO 2450:2008ISO 2450:2008(E) IDF 16:2008(
15、E) ISO and IDF 2008 All rights reserved iiiContents Page Foreword iv Foreword. v 1 Scope 1 2 Normative reference 1 3 Terms and definitions .1 4 Principle2 5 Reagents.2 6 Apparatus .2 7 Sampling.3 8 Preparation of test sample4 9 Procedure .4 9.1 Test portion 4 9.2 Blank tests4 9.3 Preparation of fat-
16、collecting vessel.5 9.4 Determination.5 10 Calculation and expression of results.7 10.1 Calculation7 10.2 Expression of results 8 11 Precision.8 11.1 Interlaboratory test 8 11.2 Repeatability.8 11.3 Reproducibility.8 12 Test report 8 Annex A (informative) Notes on procedures 9 Annex B (informative)
17、Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings .11 Bibliography 14 BS EN ISO 2450:2008ISO 2450:2008(E) IDF 16:2008(E) iv ISO and IDF 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national s
18、tandards 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
19、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 gi
20、ven 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
21、 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 2450IDF 16 was prepared by Technical Committee ISO/TC
22、34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF). It is being published jointly by ISO and IDF. This fourth edition of ISO 2450IDF 16 cancels and replaces the third edition (ISO 2450:1999), of which it constitutes a minor revision. BS EN ISO
23、2450:2008ISO 2450:2008(E) IDF 16:2008(E) ISO and IDF 2008 All rights reserved vForeword IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide. IDF membership comprises National Committees in every member country as well as regional dairy associ
24、ations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to be represented at the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO in the development of standard methods of analysis and sampling for milk and milk products. D
25、raft International Standards adopted by the Action Teams and Standing Committees are circulated to the National Committees for voting. Publication as an International Standard requires approval by at least 50 % of the IDF National Committees casting a vote. Attention is drawn to the possibility that
26、 some of the elements of this document may be the subject of patent rights. IDF shall not be held responsible for identifying any or all such patent rights. ISO 2450IDF 16 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Mi
27、lk and milk products. It is being published jointly by IDF and ISO. All work was carried out by the Joint ISO-IDF Action Team Fat of the Standing Committee on Main components in milk under the aegis of its project leader, Mr G.J. Beutick (NL). This edition of ISO 2450IDF 16 cancels and replaces IDF
28、16:1987, of which it constitutes a minor revision. BS EN ISO 2450:2008BS EN ISO 2450:2008INTERNATIONAL STANDARD ISO 2450:2008(E)IDF 16:2008(E) ISO and IDF 2008 All rights reserved 1Cream Determination of fat content Gravimetric method (Reference method) WARNING The use of this International Standard
29、 may involve hazardous materials, operations and equipment. This International Standard does not purport to address all the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish safety and health practices and determine the applicab
30、ility of regulatory limitations prior to use. 1 Scope This International Standard specifies the reference method for the determination of the fat content of raw, processed and sour cream in which no appreciable separation or breakdown of fat, due to lipolysis, has occurred. The method is not applica
31、ble to sour creams with starch or other thickening agents. NOTE If the method is not applicable and when separation or breakdown of fat occurs, a method utilizing the Weibull-Berntrop principle is suitable (see ISO 8262-3|IDF 124-33). 2 Normative reference The following referenced documents are indi
32、spensable for the application 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. ISO 835, Laboratory glassware Graduated pipettes ISO 1042, Laboratory glassware One-mark vol
33、umetric flasks ISO 3889IDF 219, Milk and milk products Specification of Mojonnier-type fat extraction flasks ISO 4788, Laboratory glassware Graduated measuring cylinders 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 fat content of cream mas
34、s fraction of substances determined by the procedure specified in this International Standard NOTE The fat content is expressed as a percentage mass fraction. BS EN ISO 2450:2008ISO 2450:2008(E) IDF 16:2008(E) 2 ISO and IDF 2008 All rights reserved4 Principle An ammoniacal ethanolic solution of a te
35、st portion is extracted with diethyl ether and light petroleum. The solvents are removed by distillation or evaporation. The mass of the substances extracted is determined. NOTE This is usually known as the Rse-Gottlieb principle. 5 Reagents Use only reagents of recognized analytical grade, unless o
36、therwise specified, and only distilled or demineralized water or water of equivalent purity. The reagents shall leave no appreciable residue when the determination is carried out by the method specified (see 9.2.2). 5.1 Ammonia solution, containing a mass fraction of NH3of approximately 25 % (20= 91
37、0 g/l). NOTE If ammonia solution of this concentration is not available, a more concentrated solution of known concentration may be used (see 9.4.2). 5.2 Ethanol (C2H5OH), or ethanol denatured by methanol, containing a volume fraction of ethanol of at least 94 %. (See Clause A.5.) 5.3 Congo red solu
38、tion Dissolve 1 g of Congo red (C32H22N6Na2O6S2) in water in a 100 ml one-mark volumetric flask (6.14). Make up to the mark with water. NOTE The use of this solution, which allows the interface between the solvent and aqueous layers to be seen more clearly, is optional (see 9.4.3). Other aqueous ind
39、icator solutions can be used provided that they do not affect the result of the determination. 5.4 Diethyl ether (C2H5OC2H5), free from peroxides (see Clause A.3), containing no more than 2 mg/kg of antioxidants, and complying with the requirements for the blank test (see 9.2.2, Clauses A.1 and A.4)
40、. WARNING The use of diethyl ether can lead to hazardous situations. Observe current safety precautions for handling, use, and disposal. 5.5 Light petroleum, with any boiling range between 30 C and 60 C or, as equivalent, pentane (CH3CH23CH3) with a boiling point of 36 C and complying with the requi
41、rements for the blank test (see 9.2.2, Clauses A.1 and A.4). The use of pentane is recommended because of its higher purity and consistent quality. 5.6 Mixed solvent Shortly before use, mix equal volumes of diethyl ether (5.4) and light petroleum (5.5). 6 Apparatus WARNING Since the determination in
42、volves the use of volatile flammable solvents, all electrical apparatus employed shall comply with legislation relating to the hazards in using such solvents. Usual laboratory equipment and, in particular, the following. 6.1 Analytical balance, capable of weighing to the nearest 1 mg, with a readabi
43、lity of 0,1 mg. BS EN ISO 2450:2008ISO 2450:2008(E) IDF 16:2008(E) ISO and IDF 2008 All rights reserved 36.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a rotational frequency of 500 min1to 600 min1to produce a radial acceleration of 80g to 90g
44、at the outer end of the flasks or tubes. The use of the centrifuge is optional but recommended (see 9.4.6). 6.3 Distillation or evaporation apparatus, for distilling the solvents and ethanol from the boiling or conical flasks, or evaporating from beakers and dishes (see 9.4.13) at a temperature not
45、exceeding 100 C. 6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of being maintained at a temperature of 102 C 2 C throughout its working space. The oven shall be fitted with a suitable thermometer. 6.5 Water bath, capable of being maintained at a temperature betwe
46、en 35 C and 50 C. 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889IDF 219. NOTE It is also possible to use fat-extraction tubes, with siphon or wash-bottle fittings, but then the procedure is different. The alternative procedure is given in Annex B. The fat-extraction flasks shall
47、be provided with good quality cork bungs or stoppers of other material e.g. silicone rubber or polytetrafluoroethylene (PTFE) unaffected by the reagents used. Cork bungs shall be extracted with the diethyl ether (5.4), kept in water at a temperature of 60 C or more for at least 15 min, and shall the
48、n be allowed to cool in the water so that they are saturated when used. 6.7 Rack, for holding the fat-extraction flasks (or tubes) (6.6). 6.8 Wash bottle, suitable for use with the mixed solvent (5.6). A plastics wash bottle shall not be used. 6.9 Fat-collecting vessels, such as boiling flasks (flat
49、-bottomed), of capacities 125 ml to 250 ml, conical flasks, of capacity 250 ml, or metal dishes. If metal dishes are used, they shall be of stainless steel, flat-bottomed with a diameter of 80 mm to 100 mm and a height of approximately 50 mm. 6.10 Boiling aids, fat-free, of non-porous porcelain or silicon carbide (optional when metal dishes are used). 6.11 Measuring cylinders, of capacities 5 ml and 25 ml, complying with the requirements of ISO 4788, class A, or any other apparatus suitable for the pro
