BS ISO 5545-2008 Rennet caseins and caseinates - Determination of ash (Reference method)《酶凝酪蛋白和酪蛋白酸盐 灰分的测定(参考方法)》.pdf

1、BRITISH STANDARDBS ISO 5545:2008Rennet caseins and caseinates Determination of ash (Reference method)ICS 67.100.99g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43

2、g55g3g47g36g58BS ISO 5545:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 February 2008 BSI 2008ISBN 978 0 580 60645 8National forewordThis British Standard is the UK implementation of ISO 5545:2008. It supersedes BS 6248-3:1982 which

3、is withdrawn. The UK participation in its preparation 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 necessar

4、y provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate CommentsReference numbersISO 5545:2008(E)IDF 90:2008(E)INTERNATIONAL STANDARD ISO5545IDF90

5、Second edition2008-01-15Rennet caseins and caseinates Determination of ash (Reference method)Casines prsure et casinates Dtermination des cendres (Mthode de rfrence) BS ISO 5545:2008ii iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standard

6、s 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 organiz

7、ations, 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

8、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 % o

9、f 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 5545IDF 90 was prepared by Technical Committee ISO/TC 34, Foo

10、d 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 5545IDF 90 cancels and replaces the first edition (ISO 5545:1978), of which it constitutes a minor revision. BS ISO 5545:2008i

11、v Foreword 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 associations having signed a formal agreement on cooperation with IDF. All members

12、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. Draft International Standards adopted by the Action Teams and Standing Committ

13、ees 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 some of the elements of this document may be the subject of patent rights. I

14、DF shall not be held responsible for identifying any or all such patent rights. ISO 5545IDF 90 was prepared by the International Dairy Federation (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

15、was carried out by the former Joint ISO-IDF-AOAC Group of Experts (E11-E701) which is now part of the Joint ISO-IDF Action Team on Physical properties and rheological tests, of the Standing Committee on Minor components and characterization of physical properties. This edition of ISO 5545IDF 90 canc

16、els and replaces IDF 90:1979, of which it constitutes a minor revision. BS ISO 5545:20081Rennet caseins and caseinates Determination of ash (Reference method) 1 Scope This International Standard specifies a reference method for the determination of the ash of caseins obtained by rennet precipitation

17、 and of caseinates, with the exception of ammonium caseinate. NOTE For the determination of ash (“fixed ash”) of acid caseins, of ammonium caseinates, of their mixtures with rennet casein and with caseinates, and of caseins of unknown type, see ISO 5544IDF 89 2. 2 Normative references The following

18、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 3310-1, Test sieves Technical requirements and testing Part

19、 1: Test sieves of metal wire cloth ISO 5550IDF 78, Caseins and caseinates Determination of moisture content (Reference method) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 ash of rennet caseins or of caseinates substances determined by th

20、e procedure described in this International Standard NOTE Ash of rennet caseins or of caseinates is conventionally expressed as a percentage by mass, numerically equivalent to grams per 100 g of product. 4 Principle A test portion is incinerated at (825 25) C. The residue is then weighed. 5 Apparatu

21、s Usual laboratory apparatus, and in particular the following. 5.1 Analytical balance, capable of weighing to the nearest 0,000 1 g. 5.2 Silica or platinum dishes, of diameter about 70 mm and of depth 25 mm to 50 mm. BS ISO 5545:20082 5.3 Electrical furnace, with air circulation, capable of being ma

22、intained at (825 25) C. 5.4 Desiccator, containing an effective desiccant. 5.5 Grinding device, for grinding the laboratory sample, if necessary (see 7.1.4), without development of undue heat and without loss or absorption of moisture. A hammer-mill shall not be used. 5.6 Test sieve, wire cloth, dia

23、meter 200 mm, nominal size of aperture 500 m, with receiver, complying with ISO 3310-1. 6 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 Internation

24、al Standard. A recommended sampling method is given in ISO 707|IDF 50 1. 7 Procedure 7.1 Preparation of the test sample 7.1.1 Thoroughly mix the laboratory sample by repeatedly shaking and inverting the container (if necessary, after having transferred all of the laboratory sample to an airtight con

25、tainer of sufficient capacity to allow this operation to be carried out). 7.1.2 Transfer about 50 g of the thoroughly mixed laboratory sample to the test sieve (5.6). 7.1.3 If the 50 g portion directly passes or almost completely passes the sieve, use for the determination the sample as prepared in

26、7.1.1. 7.1.4 Otherwise, grind the 50 g portion, using the grinding device (5.5), until it passes the sieve. Immediately transfer all of the sieved sample to an airtight container of sufficient capacity and mix thoroughly by repeatedly shaking and inverting. During these operations, take precautions

27、to avoid any change in the water content of the product. 7.1.5 After the test sample has been prepared, the determination (7.4) should proceed as soon as possible. Clean the device after grinding each sample. 7.2 Preparation of the dish Heat the dish (5.2) in the electrical furnace (5.3), maintained

28、 at 825 C, for 30 min. Allow the dish to cool in the desiccator (5.4) to the temperature of the balance room and weigh to the nearest 0,1 mg. 7.3 Test portion Weigh, to the nearest 0,1 mg, directly in or by difference approximately 3,000 0 g of the test sample (7.1) into the prepared dishes. 7.4 Det

29、ermination Heat the dish containing the test portion on a low flame until the test portion is completely charred, taking care that it does not burst into flame. BS ISO 5545:20083Transfer the dish to the electrical furnace (5.3), maintained at (825 25) C, and heat for at least 1 h until all carbon ha

30、s disappeared from the dish. Allow the dish to cool in the desiccator (5.4) to the temperature of the balance room and weigh to the nearest 0,1 mg. Repeat the operations of heating in the electrical furnace (5.3), cooling and weighing, until the mass remains constant to within 1 mg or begins to incr

31、ease. Record the minimum mass. 8 Expression of results 8.1 Calculation 8.1.1 The ash of the sample, wa, as a percentage by mass, is given by Equation (1): mmwm=12a0100 (1) where m0is the mass, in grams, of the test portion (7.3); m1is the mass, in grams, of dish and residue (7.4); m2is the mass, in

32、grams, of the prepared dish (7.2). Calculate the ash to the nearest 0,01 % by mass and report the final result to the nearest 0,1 % by mass. 8.1.2 To calculate the ash of the sample on the dry basis, as a percentage by mass, multiply the result obtained from Equation (1) by Factor (2): ww100100(2) w

33、here wwis the water content, as a percentage by mass, of the sample determined according to ISO 5550IDF 78. 8.2 Precision 8.2.1 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the s

34、ame operator using the same equipment within a short interval of time will in not more than 5 % of cases be greater than 0,15 g of ash per 100 g of product (numerically equivalent to 0,15 % by mass). 8.2.2 Reproducibility The absolute difference between two independent single test results, obtained

35、using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than 0,25 g of ash per 100 g of product (numerically equivalent to 0,25 % by mass). BS ISO 5545:20084 9 Test report The test re

36、port shall specify: a) all the information required for the complete identification of the sample; b) the sampling method used, if known; c) the test method used, together with a reference to this International Standard; d) all operating details not specified in this International Standard, or regar

37、ded as optional, together with details of any incident that may have influenced the result(s); e) the test result(s) obtained, and if the repeatability has been checked, the final quoted results obtained. BS ISO 5545:20085Bibliography 1 ISO 707|IDF 50, Milk and milk products Guidance on sampling 2 I

38、SO 5544IDF 89, Caseins Determination of “fixed ash” (Reference method) BS ISO 5545:2008BS ISO 5545:2008BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europ

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