1、BS EN ISO1736:2008ICS 67.100.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDDried milk and driedmilk products Determination of fatcontent Gravimetricmethod (Referencemethod)(ISO 1736:2008)This British Standard was published under theauthority of the Standards
2、Policy and StrategyCommittee on 31 ber 2008 BSI 2008ISBN 978 0 580 63533 5Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 1736:2008National forewordThis British Standard is the UK implementation of EN ISO 1736:2008. Itsupersedes BS EN ISO 1736:2000 which is withdrawn.The UK part
3、icipation in its preparation 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.
4、Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.DecemEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 1736October 2008ICS 67.100.10 Supersedes EN ISO 1736:2000 English VersionDried milk and dried milk products - D
5、etermination of fat content- Gravimetric method (Reference method) (ISO 1736:2008)Lait sec et produits base de lait sec - Dtermination de lateneur en matire grasse - Mthode gravimtrique(Mthode de rfrence) (ISO 1736:2008)Milchpulver und Trockenmilcherzeugnisse - Bestimmungdes Fettgehaltes - Gravimetr
6、isches Verfahren(Referenzverfahren) (ISO 1736:2008)This European Standard was approved by CEN on 14 October 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 alt
7、eration. 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 tran
8、slationunder 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,
9、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 STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagemen
10、t Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 1736:2008: EBS EN ISO 1736:2008EN ISO 1736:2008 (E) 3 Foreword This document (EN ISO 1736:2008) has been prepared by Technical Com
11、mittee ISO/TC 34 “Agricultural 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
12、 identical text or by endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the 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 hel
13、d responsible for identifying any or all such patent rights. This document supersedes EN ISO 1736:2000. 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, Cyprus
14、, 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 the United Kingdom. Endorsement notice The text of ISO 1736
15、:2008 has been approved by CEN as a EN ISO 1736:2008 without any modification. BS EN ISO 1736:2008ISO 1736:2008(E) IDF 9:2008(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 membershi
16、p comprises National Committees in every member country as well as regional dairy associations 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 th
17、e development of standard methods of analysis and sampling for milk and milk products. Draft 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 % o
18、f the IDF National Committees casting a vote. Attention is drawn to the possibility that 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 1736IDF 9 was prepared by the International Dairy F
19、ederation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk 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
20、 leader, Mr G.J. Beutick (NL). This edition of ISO 1736IDF 9 cancels and replaces IDF 9:1987, of which it constitutes a minor revision. BS EN ISO 1736:2008BS EN ISO 1736:2008INTERNATIONAL STANDARD ISO 1736:2008(E)IDF 9:2008(E) ISO and IDF 2008 All rights reserved 1Dried milk and dried milk products
21、Determination of fat content Gravimetric method (Reference method) WARNING The use of this International Standard 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 responsibili
22、ty of the user of this International Standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies the reference method for the determination of the fat content of dried milk and dried milk prod
23、ucts. The method is also applicable to dried milk with a fat content of 40 % mass fraction or more, dried whole, dried partially skimmed, and dried skimmed milk, dried whey, dried buttermilk and dried butter serum. The method is not applicable when the powder contains hard lumps which do not dissolv
24、e in ammonia solution or free fatty acids in significant quantities. NOTE When the powder contains hard lumps which do not dissolve in ammonia solution or contains free fatty acids in significant quantities, noticeable by a distinct smell, the result of the determination will be too low. With such p
25、roducts, a method using the Weibull-Berntrop principle is suitable (see ISO 8262-3IDF 124-33). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest ed
26、ition of the referenced document (including any amendments) applies. ISO 835, Laboratory glassware Graduated pipettes ISO 1042, Laboratory glassware One-mark volumetric flasks ISO 3889IDF 219, Milk and milk products Specification of Mojonnier-type fat extraction flasks ISO 4788, Laboratory glassware
27、 Graduated measuring cylinders 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 fat content of dried milk and dried milk products mass fraction of substances determined by the procedure specified in this International Standard NOTE The fat con
28、tent is expressed as a percentage mass fraction. BS EN ISO 1736:2008ISO 1736:2008(E) IDF 9:2008(E) 2 ISO and IDF 2008 All rights reserved4 Principle An ammoniacal ethanolic solution of a test portion is extracted with diethyl ether and light petroleum. The solvents are removed by distillation or eva
29、poration. 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 otherwise specified, and only distilled or demineralized water or water of equivalent purity. The reagents shall
30、 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= 910 g/l). NOTE If ammonia solution of this concentration is not available, a more concentrated solution of known
31、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 solution. Dissolve 1 g of Congo red (C32H22N6Na2O6S2) in water in a 100 ml one-mark volumetric flask (6.14). Make u
32、p 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 9.4.4). Other aqueous indicator solutions can be used provided that they do not affect the result of the determination. 5.4 Diethyl eth
33、er (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). WARNING The use of diethyl ether can lead to hazardous situations. Observe current safety precautions for ha
34、ndling, 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 requirements for the blank test (see 9.2.2, Clauses A.1 and A.4). The use of pentane is recommended because of its
35、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 involves the use of volatile flammable solvents, all electrical apparatus employed shall comply with legislatio
36、n 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 readability of 0,1 mg. BS EN ISO 1736:2008ISO 1736:2008(E) IDF 9:2008(E) ISO and IDF 2008 All rights reserved 36.2 C
37、entrifuge, 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 at the outer end of the flasks or tubes. The use of the centrifuge is optional but recommended (see 9.4.7). 6.
38、3 Distillation or evaporation apparatus, for distilling the solvents and ethanol from the boiling or conical flasks, or evaporating from beakers and dishes (see 9.4.14) at a temperature not exceeding 100 C. 6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of being m
39、aintained 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 of 65 C 5 C. 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889IDF 219. NOTE It is also possible to
40、 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 be provided with good quality cork bungs or stoppers of another material (e.g. silicone rubber or polytetrafluoroethylene
41、) 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 then be allowed to cool in the water so that they are saturated when used. 6.7 Rack, for holding the fat-extraction flasks (or
42、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-bottomed), of capacities 125 ml to 250 ml, conical flasks, of capacity 250 ml, or metal dishes. If metal dishes are used, t
43、hey 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
44、 the requirements of ISO 4788, class A, or any other apparatus suitable for the product concerned. 6.12 Pipettes, graduated, of capacity 10 ml, complying with the requirements of ISO 835, class A. 6.13 Tongs, made of metal, for holding flasks, beakers or dishes. 6.14 Volumetric flask, one-mark, of c
45、apacity 100 ml, complying with the requirements of ISO 1042, class A. 7 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. Sampling is not part of the method specified in this International Standard. A rec
46、ommended sampling method is given in ISO 707IDF 501. Store laboratory samples at a temperature between 2 C and 6 C from the time of sampling to the time of commencing the procedure. BS EN ISO 1736:2008ISO 1736:2008(E) IDF 9:2008(E) 4 ISO and IDF 2008 All rights reserved8 Preparation of test sample T
47、horoughly mix the test sample by repeatedly rotating and inverting the sample container. If necessary, transfer all of the test sample to an airtight container of approximately twice the volume of the test sample to allow this operation to be carried out. 9 Procedure NOTE 1 If it is required to chec
48、k whether the repeatability limit (11.2) is met, carry out two single determinations in accordance with 9.1 to 9.4. NOTE 2 An alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings (see Note to 6.6) is given in Annex B. 9.1 Test portion Mix the test sample (Clause 8) by
49、 gently stirring or rotating and inverting the container several times. Immediately weigh, to the nearest 1 mg, directly or by difference, in a fat-extraction flask (6.6), one of the following test portions: a) about 1,000 g of dried high-fat milk, of dried whole milk or of dried butter serum; b) about 1,500 g of dried partially skimmed milk; c) about 1,500 g of dried skimmed milk; d) about 1,500 g of dried whey; e) about 1,500 g of dried buttermilk. Transfer the test portion as completely as possible
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