1、BRITISH STANDARD BS ISO 5543:2004 Caseins and caseinates Determination of fat content G r a v i m e t r i c m e t h o d (Reference method) ICS 67.100.99 BS ISO 5543:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 7 December 2004 BSI 7 De
2、cember 2004 ISBN 0 580 44985 8 National foreword This British Standard reproduces verbatim ISO 5543:2004 and implements it as the UK national standard. It supersedes BS 6248-10:1986 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/5, Milk and milk p
3、roducts, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the sect
4、ion entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. C
5、ompliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor rel
6、ated international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to vi, pages 1 to 14, an inside back cover and a back cover. The BSI copyright notice displayed in this document ind
7、icates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference numbers ISO 5543:2004(E) IDF 127:2004(E) OSI DI dnaF 4002INTERNATIONAL STANDARD ISO 5543 IDF 127 Second edition 2004-12-01 Caseins and caseinates Determination of fat content Gravimetric me
8、thod (Reference method) Casines et casinates Dtermination de la teneur en matire grasse Mthode gravimtrique (Mthode de rfrence) BSISO5543:2004IS:3455 O4002(E) ID:721 F4002(E) DPlcsid Fremia ihTs PDF file may ctnoian emdebt dedyfepcaes. In ccaocnadrw eith Aebods licensilop gnic,y this file mairp eb y
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14、er edevrBSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E I SO dna ID 4002 F All irhgts seredevr iiiContents Page Foreword iv Introduction . vi 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle . 1 5 Reagents 1 6 Apparatus and materials 2 7 Sampling 3 8 Procedure. 3 8.1 Prepar
15、ation of test sample. 4 8.2 Test portion . 4 8.3 Blank test . 4 8.4 Preparation of fat-collecting vessel 4 8.5 Determination 4 9 Calculation and expression of results 7 10 Precision 8 10.1 Interlaboratory test . 8 10.2 Repeatability 8 10.3 Reproducibility 8 11 Notes on procedure 8 11.1 Blank test to
16、 check the reagents. 8 11.2 Blank test carried out simultaneously with the determination 9 11.3 Test for peroxides in diethyl ether 9 11.4 Diethyl ether containing antioxidants. 9 12 Test report 10 Annex A (informative) Alternative procedure using fat-extraction tubes with siphon or wash- bottle fit
17、tings . 11 Bibliography . 14 BSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E iv I SO dna ID 4002 F All irhgts seredevrForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stand
18、ards 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 ta
19、ke 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 i
20、s 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 possibili
21、ty 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 5543 IDF 127 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the Intern
22、ational Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. This edition of ISO 5543 IDF 127 cancels and replaces ISO 5543:1986, of which it constitutes a minor revision. Only editorial changes have been
23、 made. BSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E I SO dna ID 4002 F All irhgts seredevr vForeword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National Committee has the right to be represented on
24、 the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO and AOAC International in the 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
25、to the National Committees for voting. Publication as an International Standard requires approval by at least 50 % of the National Committees casting a vote. ISO 5543 IDF 127 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the Internationa
26、l Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. All work was carried out by the Joint ISO/IDF/AOAC Group of Experts, Fat determination (E31), under the aegis of its project leader, Mr J. Eisses (NL
27、). This edition of ISO 5543 IDF 127 cancels and replaces IDF 127A:1988. Only editorial changes have been made. BSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E vi I SO dna ID 4002 F All irhgts seredevrIntroduction This International Standard has been prepared within the framework of producing a series
28、 of methods, which are harmonized to the greatest possible extent, for the gravimetric determination of the fat content of milk, milk products and milk-based food. A method based on the principle of Schmid-Bondzynski-Ratzlaff (SBR), involving digestion with hydrochloric acid, has been chosen for the
29、 following reasons: a) many caseins do not readily dissolve in ammonia, either because they contain or consist of hard lumps, or because they are not soluble, or are only poorly soluble (e.g. rennet casein), and therefore cannot be examined according to the method based on the Rse-Gottlieb (RG) prin
30、ciple as used for milk and most milk products; b) all caseins and caseinates, due to their low lactose content less than 5 % (mass fraction) of dry matter, can be examined according to the SBR principle; this has the advantage over the Weibull method in that the method can be carried out using the s
31、ame apparatus as that specified for the RG method and, at the same time, is less time consuming; c) methods based on the SBR principle have already found wide application in many countries as official or standardized methods for the examination of all caseins and caseinates. BSISO5543:2004NITERNATNO
32、IAL STANDARD IS:3455 O4002(E) ID:721 F002(4)EI SO dna ID 4002 F All irhgts seredevr 1Caseins and caseinates Determination of fat content Gravimetric method (Reference method) 1 Scope This International Standard specifies the reference method for the determination of the fat content of all types of c
33、aseins and caseinates. 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 edition of the referenced document (including any amendments) applies. ISO
34、 565, Test sieves Metal wire cloth, perforated metal plate and electroformed sheet Nominal sizes of openings ISO 3889, Milk and milk products Determination of fat content Mojonnier-type fat extraction flasks ISO 5550, Caseins and caseinates Determination of water content (Reference method) 3 Terms a
35、nd definitions For the purposes of this document, the following terms and definitions apply. 3.1 fat content of caseins and caseinates all the substances determined by the method specified in this International Standard NOTE It is expressed as a mass fraction in percent. 4 Principle A test portion i
36、s digested with hydrochloric acid, then ethanol is added. The acid-ethanolic solution is subsequently extracted with diethyl ether and light petroleum, then the solvents are removed by distillation or evaporation.The mass of the substances extracted, which are soluble in light petroleum, is determin
37、ed. (This is usually known as the Schmid-Bondzynski-Ratzlaff principle.) 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water or water of equivalent purity. BSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E 2 I SO dna ID 4002 F Al
38、l irhgts seredevrTo test the quality of the reagents, carry out a blank test as specified in 8.3. Use an empty fat-collecting vessel, prepared as specified in 8.4, for mass control purposes (see 11.1). The reagents shall leave no residue greater than 0,5 mg. If the residue of the complete reagent bl
39、ank test is greater than 0,5 mg, determine the residue of the solvents separately by distilling 100 ml of the diethyl ether and light petroleum respectively. Use an empty control vessel to obtain the real mass of residue, which shall not exceed 0,5 mg. Replace unsatisfactory reagents or solvents, or
40、 redistil solvents. 5.1 Dilute hydrochloric acid solution, 20(HCl) 1,125 g/ml. (See also Note in 8.5.1.) Dilute 675 ml of hydrochloric acid 20(HCl) = 1,18 g/ml to 1 000 ml with water. 5.2 Ethanol (C 2 H 5 OH) or methanol (CH 3 OH), at least 94 % (volume fraction). Ethanol denatured otherwise than by
41、 methanol may be used provided that the denaturant does not affect the result of the determination. 5.3 Diethyl ether (C 2 H 5 OC 2 H 5 ), free from peroxides (see 11.3) and containing none or not more than 2 mg/kg of antioxidants, and complying with the requirements for the blank test (see the intr
42、oductory paragraphs to this clause, and also 11.1 and 11.4). 5.4 Light petroleum, having any boiling range between 30 C and 60 C. 5.5 Mixed solvent, prepared shortly before use by mixing equal volumes of the diethyl ether (5.3) and the light petroleum (5.4). 5.6 Congo red solution. Dissolve 1 g of C
43、ongo red in water and dilute to 100 ml. NOTE The use of this solution, which allows the interface between the solvent and aqueous layers to be seen more clearly, is optional (see 8.5.4) and only useful with products giving colourless or only slightly coloured digests. Other aqueous colour solutions
44、may be used provided that they do not affect the result of the determination. 6 Apparatus and materials WARNING Since the determination involves the use of volatile flammable solvents, electrical apparatus employed may be required to comply with legislation relating to the hazards in using such solv
45、ents. 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. 6.2 Centrifuge, in which the stoppered fat-extraction flasks or tubes (6.6) can be spun at a rotational frequency of 500 min 1to 600 min
46、1to produce a gravitational field of 80g and 90g at the outer end of the flasks or tubes. NOTE The use of the centrifuge is optional but recommended (see 8.5.7). 6.3 Distillation or evaporation apparatus, to enable the solvents and ethanol to be distilled from the fat- collecting flasks or to be eva
47、porated from beakers and dishes (see 8.5.10 and 8.5.12) at a temperature not exceeding 100 C. BSISO5543:2004IS:3455 O4002(E) ID:721 F002(4)E I SO dna ID 4002 F All irhgts seredevr 36.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of being maintained at 102 C 2 C thr
48、oughout the working space, and fitted with a suitable thermometer; or vacuum drying oven, capable of being maintained at 70 C to 75 C, at a pressure less than 600 mbar (50 mmHg). 6.5 Boiling water bath or hotplate (see 8.5.2). 6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889 (but s
49、ee the Note in 8.5.2). NOTE It is also possible to use fat-extraction tubes (or flasks) with siphon or wash-bottle fittings, but the procedure is then different and is specified in Annex A. The long inner limb of the fitting may have a hooked end if desired. The flasks (or tubes, see Note) shall be provided with good quality bark corks or stoppers of another material e.g. silicone rubber or polytetrafluo
