1、 Reference numbers ISO 8851-1:2004(E) IDF 191-1:2004(E) ISO and IDF 2004INTERNATIONAL STANDARD ISO 8851-1 IDF 191-1 First edition 2004-05-15 Butter Determination of moisture, non-fat solids and fat contents (Routine methods) Part 1: Determination of moisture content Beurre Dtermination des teneurs e
2、n eau, en matire sche non grasse et en matire grasse (Mthodes de routine) Partie 1: Dtermination de la teneur en eau ISO 8851-1:2004(E) IDF 191-1:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but sh
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5、s suitable for use by ISO member bodies and IDF national committees. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. ISO and IDF 2004 All rights reserved. Unless otherwise specified, no part of this publication may b
6、e reproduced or utilized in any form 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 Bu
7、ilding Boulevard Auguste Reyers 80 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 2004 All rights reservedISO 8851-1:200
8、4(E) IDF 191-1:2004(E) ISO and IDF 2004 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical com
9、mittees. 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 take part in the work. ISO collaborates closely with the
10、 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 is to prepare International Standards. Draft Internatio
11、nal 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 possibility that some of the elements of this document may be t
12、he subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 8851-1IDF 191-1 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration wi
13、th AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. ISO 8851IDF 191 consists of the following parts, under the general title Butter Determination of moisture, non-fat solids and fat contents (Routine methods): Part 1: Determination of moisture co
14、ntent Part 2: Determination of non-fat solids content Part 3: Calculation of fat content ISO 8851-1:2004(E) IDF 191-1:2004(E) iv ISO and IDF 2004 All rights reservedForeword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every memb
15、er country. Every National Committee has the right to be represented on 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 Standa
16、rds 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 National Committees casting a vote. ISO 8851-1IDF 191-1 was prepared by Technical Committee ISO/TC 34, Food
17、 products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. ISO 8851IDF 191 consists of the following parts, under the general title Bu
18、tter Determination of moisture, non-fat solids and fat contents (Routine methods): Part 1: Determination of moisture content Part 2: Determination of non-fat solids content Part 3: Calculation of fat content This first edition of ISO 8851-1IDF 191-1 cancels and replaces the first edition of IDF 137:
19、1986, which has been technically revised. All work was carried out by the Joint ISO/IDF/AOAC Action Team on Water, of the Standing Committee on Main components of milk, under the aegis of its project leader, Mr J. Evers (NZ). INTERNATIONAL STANDARD ISO 8851-1:2004(E) IDF 191-1:2004(E) ISO and IDF 20
20、04 All rights reserved 1Butter Determination of moisture, non-fat solids and fat contents (Routine methods) Part 1: Determination of moisture content WARNING The use of this International Standard may involve hazardous materials, operations and equipment. This standard does not purport to address al
21、l the safety problems associated with its use. It is the responsibility of the user of this standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 8851IDF 191 specifies the routine method for the determinatio
22、n of the moisture content of butter. 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
23、) applies. ISO 3727-1IDF 80-1, Butter Determination of moisture, non-fat solids and fat contents Part 1: Determination of moisture content (Reference method) ISO 8851-2IDF 191-2, Butter Determination of moisture, non-fat solids and fat contents (Routine method) Part 2: Determination of non-fat solid
24、s content 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 moisture content mass fraction of substances determined by the procedure specified in this part of ISO 8851IDF 191 NOTE The moisture content is expressed as a percentage by mass. 4 Pri
25、nciple A known mass of butter is heated under controlled conditions in an open beaker to evaporate the volatile constituents. The loss of mass is determined. ISO 8851-1:2004(E) IDF 191-1:2004(E) 2 ISO and IDF 2004 All rights reserved5 Apparatus Usual laboratory equipment and, in particular, the foll
26、owing. 5.1 Analytical balance, capable of weighing to the nearest 1 mg. 5.2 Drying oven, electrically heated, ventilated, thermostatically controlled, capable of being maintained at a temperature of 102 C 2 C throughout its working space. 5.3 Heating apparatus, for example an electric hot plate, Bun
27、sen burner, Teclu-burner or spirit (alcohol) burner. 5.4 Beaker, made of aluminium, stainless steel or glass, with smooth surface, of such dimensions that losses by spattering or frothing are avoided. If desired, the beaker may be provided with a glass stirring rod. Recommended dimensions are diamet
28、er 60 mm to 80 mm, and height 50 mm to 70 mm. NOTE A 250 ml glass beaker meets the recommended dimensions. 5.5 Beaker tongs, to hold the beaker (5.4) by its outer surface only. 5.6 Stone or metal plate, flat, to allow rapid cooling of the beaker (5.4). 6 Sampling It is important that the laboratory
29、receive a sample that is truly representative and that has not 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 707. The laboratory sample should be received in an airtight
30、container. The capacity of the container shall be such that one-half to two-thirds is filled by the sample. Store the samples in the closed container at a temperature of between 5 C and 14 C until commencing the preparation of the test sample. 7 Preparation of test sample 7.1 Warm the test sample in
31、 the original unopened container to a temperature at which the sample will be soft enough to facilitate thorough mixing to a homogeneous state (either by a mechanical shaker or by hand) without any rupture of the emulsion. The temperature of mixing should typically be between 24 C and 28 C, and shal
32、l normally not exceed 35 C. 7.2 Where applicable, cool the test sample to ambient temperature while mixing until cooling is complete. As soon as possible after cooling, open the sample container and stir briefly for no longer than 10 s with a suitable device (e.g. a spoon or spatula) before weighing
33、. 8 Procedure 8.1 Preparation of the beaker 8.1.1 Dry the empty beaker (5.4) (with rod if used) in the drying oven (5.2), set at 102 C, for at least 1 h. ISO 8851-1:2004(E) IDF 191-1:2004(E) ISO and IDF 2004 All rights reserved 38.1.2 Allow the empty beaker to cool on the stone or metal plate (5.6).
34、 Weigh it to the nearest 1 mg. NOTE Generally a cooling time of 15 min is sufficient. 8.2 Determination 8.2.1 Weigh, to the nearest 1 mg, 5 g to 10 g of test sample (7.2) into the prepared beaker (8.1.2). If the dried test portion remaining from this determination will also be used for the determina
35、tion of the non-fat solids content described in ISO 8851-2IDF 191-2, weigh, to the nearest 1 mg, 9,5 g to 10,5 g of test sample (7.2) into the prepared beaker (8.1.2). 8.2.2 Heat the beaker and its contents, agitating continuously by swirling the beaker on or over the heating apparatus (5.3), or by
36、stirring the contents with the glass rod. Use beaker tongs (5.5), if necessary, to handle the beakers. Control the heating and agitation so that losses by spattering and frothing are avoided. Continue the heating until frothing stops, the foam has broken and the colour of the non-fat solids has beco
37、me light brown or yellow brown. If using a hot plate (5.3), it is recommended to use a heating temperature between 120 C and 160 C. However, butter manufactured according to the Ammix process may require a lower temperature than 120 C at the beginning of the heating process to avoid spattering of th
38、e test portion. In this case, the final temperature of the contents of the beaker shall be between 140 C and 160 C to ensure all moisture is removed. NOTE Normally, the heating time should not exceed 20 min. The determination of the endpoint of the heating process involves a subjective assessment. T
39、herefore, periodically check the obtained results with this method against those obtained with the reference method described in ISO 3727-1IDF 80-1. 8.2.3 Allow the beaker and its contents to cool on the stone or metal plate (5.6). Weigh to the nearest 1 mg. NOTE Generally a cooling time of 15 min i
40、s sufficient. 9 Calculation and expression of results 9.1 Calculation Calculate the moisture content of the test sample, w m , in percent by mass, by using the following equation: 12 m 10 () 100 % () mm w mm = where m 0is the mass, in grams, of the empty beaker (with rod if used) (8.1.2); m 1is the
41、mass, in grams, of the test portion and beaker (with rod if used) before heating (8.2.1); m 2is the mass, in grams, of the test portion and beaker (with rod if used) after heating (8.2.3). 9.2 Expression of results Express the test results to one decimal place. ISO 8851-1:2004(E) IDF 191-1:2004(E) 4
42、 ISO and IDF 2004 All rights reserved10 Precision 10.1 Interlaboratory tests Details of interlaboratory tests on the precision of the method are given in Annex A. The values derived from these interlaboratory tests may not be applicable to concentration ranges and matrices other than those given. 10
43、.2 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 same operator using the same equipment within a short interval of time, will in not more than 5 % of cases be greater than 0,3
44、1 %. 10.3 Reproducibility The absolute difference between two single test results, obtained 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 0,42 %. 11 Test report The tes
45、t report shall specify: a) all information necessary for the complete identification of the sample; b) the sampling method used, if known; c) the test method used, with reference to this part of ISO 8851IDF 191; d) all operating details not specified in this part of ISO 8851IDF 191, or regarded as o
46、ptional, together with details of any incident that may have influenced the result(s); e) the test result(s) obtained or, if the repeatability has been checked, the final quoted results obtained. ISO 8851-1:2004(E) IDF 191-1:2004(E) ISO and IDF 2004 All rights reserved 5Annex A (informative) Results
47、 of interlaboratory trials The results obtained from two collaborative studies 4, 5were subjected to statistical analysis in accordance with ISO 5725-1 and ISO 5725-2. Additionally, a meta-analysis was performed to calculate pooled precision estimates for repeatability and reproducibility using the
48、following equation 5 : 2 2 p ii i x x = where x p is the pooled estimate for repeatability or reproducibility; x i is the ithestimate of repeatability or reproducibility for each study; iis the number of degrees of freedom associated with estimate x i . Table A.1 Results of interlaboratory tests Mea
49、n rbRcRSD(r)dRSD(R)eSample Bibliographic reference Number of labs. %a%a%a% % Salted Ammix 4 9 15,61 0,39 0,40 0,89 0,91 Low salt Ammix 4 9 15,62 0,30 0,35 0,68 0,79 Unsalted Fritz 4 9 15,36 0,20 0,29 0,45 0,67 Salted Fritz 4 9 15,71 0,12 0,25 0,26 0,57 Salted Fritz 4 9 15,75 0,21 0,25 0,47 0,57 Salted Fritz 4 9 15,75 0,64 0,65 1,44 1,46 Unsalted Fritz 4 9 15,81 0,30 0,45 0,68 1,02 Salted Fritz 5 9 15,74 0,11 0,24 0,37 0,84 Unsalted Fritz 5
