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1、 Reference numbers ISO 1737:2008(E) IDF 13:2008(E) ISO and IDF 2008 INTERNATIONAL STANDARD ISO 1737 IDF 13 Fourth edition 2008-10-15 Evaporated milk and sweetened condensed milk Determination of fat content Gravimetric method (Reference method) Lait concentr sucr et non sucr Dtermination de la teneu
2、r en matire grasse Mthode gravimtrique (Mthode de rfrence) ISO 1737:2008(E) IDF 13:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are l
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5、tees. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO and IDF 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any fo
6、rm or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO or IDF at the respective address below. ISO copyright office International Dairy Federation Case postale 56 CH-1211 Geneva 20 Diamant Building Boulevard Auguste Reyers 80
7、 B-1030 Brussels Tel. + 41 22 749 01 11 Tel. + 32 2 733 98 88 Fax + 41 22 749 09 47 Fax + 32 2 733 04 13 E-mail copyrightiso.org E-mail infofil-idf.org Web www.iso.org Web www.fil-idf.org Published in Switzerland ii ISO and IDF 2008 All rights reserved -,-,- ISO 1737:2008(E) IDF 13:2008(E) ISO and I
8、DF 2008 All rights reserved iii Contents Page Foreword iv Foreword. v 1 Scope 1 2 Normative references1 3 Term and definitions .1 4 Principle1 5 Reagents.2 6 Apparatus .2 7 Sampling.3 8 Preparation of test sample4 8.1 Evaporated milk.4 8.2 Sweetened condensed milk4 9 Procedure .4 9.1 Test portion4 9
9、.2 Blank tests4 9.3 Preparation of fat-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 test8 11.2 Repeatability.8 11.3 Reproducibility.8 12 Test report9 Annex A (informative) Notes o
10、n procedures10 Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings.12 Bibliography15 ISO 1737:2008(E) IDF 13:2008(E) iv ISO and IDF 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federat
11、ion 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 committe
12、e. 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
13、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 app
14、roval 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 1737IDF 13 was prepared by Technical
15、Committee ISO/TC 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 1737IDF 13 cancels and replaces the third edition (ISO 1737:1999), of which it constitutes a minor rev
16、ision. ISO 1737:2008(E) IDF 13:2008(E) ISO and IDF 2008 All rights reserved 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 associa
17、tions 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. Dr
18、aft 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
19、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 1737IDF 13 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Mil
20、k 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 1737IDF 13 cancels and replaces IDF 1
21、3:1987, of which it constitutes a minor revision. -,-,- -,-,- INTERNATIONAL STANDARD ISO 1737:2008(E) IDF 13:2008(E) ISO and IDF 2008 All rights reserved 1 Evaporated milk and sweetened condensed milk Determination of fat content Gravimetric method (Reference method) WARNING The use of this Internat
22、ional 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 responsibility of the user of this International Standard to establish safety and health practices and determin
23、e 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 all types of evaporated milk and sweetened condensed milk (liquid sweetened and unsweetened concentrated milk). 2 Normative refer
24、ences 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 835, Laboratory glassware Graduated pip
25、ettes 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 Graduated measuring cylinders 3 Term and definitions For the purposes of this document, the following terms and
26、 definitions apply. 3.1 fat content of evaporated milk and sweetened condensed milk mass fraction of substances determined by the procedure specified in this International Standard NOTE The fat content is expressed as a percentage mass fraction. 4 Principle An ammoniacal ethanolic solution of a test
27、 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. -,-,- ISO 1737:2008(E) IDF 13:2008(E) 2 ISO and IDF 2008 All rights res
28、erved 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and 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 so
29、lution, containing a mass fraction of NH3 of approximately 25 % (20 = 910 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 fr
30、action 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 up to the mark with water. NOTE The use of this solution, which allows the interface between the solvent and aqueous la
31、yers to be seen more clearly, is optional (see 9.4.3). Other aqueous indicator 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 w
32、ith 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 handling, use, and disposal. 5.5 Light petroleum, with any boiling range between 30 C and 60 C or, as equivalent, pentan
33、e (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 higher purity and consistent quality. 5.6 Mixed solvent Shortly before use, mix equal volumes of diethyl ether (5.4) a
34、nd light petroleum (5.5). 6 Apparatus WARNING Since the determination involves 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 Ana
35、lytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg. 6.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a rotational frequency of 500 min1 to 600 min1 to produce a radial acceleration of 80g to 90g at the outer en
36、d 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 exceeding 100 C
37、. -,-,- ISO 1737:2008(E) IDF 13:2008(E) ISO and IDF 2008 All rights reserved 3 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
38、Water baths, capable of being maintained at a temperature of between 30 C and 40 C, and 40 C and 60 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 differ
39、ent. The alternative procedure is given in Annex B. The fat-extraction flasks shall be provided with good quality cork bungs or stoppers of other material (e.g. silicone rubber or polytetrafluoroethylene) unaffected by the reagents used. Cork bungs shall be extracted with the diethyl ether (5.4), ke
40、pt 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 tubes) (6.6). 6.8 Wash bottle, suitable for use with the mixed solvent (5.6). A plastics wash bot
41、tle 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, they shall be of stainless steel, flat-bottomed with a diameter of 80 mm to 100 mm and a height of
42、 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 product concerned
43、. 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 capacity 100 ml, complying with the requirements of ISO 1042, class A. 7 Sampling A representative
44、 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 recommended sampling method is given in ISO 707IDF 501. Store laboratory samples at a temperature be
45、tween 2 C and 6 C from the time of sampling to the time of commencing the procedure. Store samples in sealed cans unopened at a temperature below 20 C. -,-,- ISO 1737:2008(E) IDF 13:2008(E) 4 ISO and IDF 2008 All rights reserved 8 Preparation of test sample 8.1 Evaporated milk Shake and invert the s
46、ample container. Open the sample container and pour the sample slowly into a second sample container (provided with an airtight lid). Mix by repeated transfer, taking care to incorporate in the sample any fat or other constituent adhering to the wall and ends of the first container. Finally, transfe
47、r the product as completely as possible to the second container. If necessary in the case of samples in sealed cans, condition the unopened container in the water bath (6.5) maintained at a temperature of between 40 C and 60 C. Remove and shake the can vigorously every 15 min. After 2 h, remove the
48、can and allow it to cool to room temperature. Remove the lid entirely and thoroughly mix the sample by stirring with a spoon or spatula. (If fat separates, do not test the sample.) 8.2 Sweetened condensed milk Open the sample container and mix thoroughly with a spoon or spatula. Use an up-and-down rotary movement in such a way that the top layers and the content of the lower corners of the container are moved and mixed. Take care to incorporate in the sample any milk adhering to the wall and ends of the container. Transfer th