BS 4401-5-1996 Methods of test for meat and meat products - Determination of free fat content《肉及肉制品试验方法 第5部分 游离脂肪含量测定》.pdf

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1、BRITISH STANDARD BS4401-5: 1996 ISO1444: 1996 Methods of test for Meat and meat products Part 5: Determination of free fat content ICS67.120.10BS4401-5:1996 This British Standard, having been prepared under the directionof the Consumer Products and Services Sector Board, was published under theautho

2、rity of the Standards Board and comes into effect on 15July1996 BSI 03-1999 First published November1970 Second edition July1996 The following BSI references relate to the work on this standard: Committee reference AW/6 Draft for comment94/504807DC ISBN 0 580 26138 7 Committees responsible for this

3、British Standard The preparation of this British Standard was entrusted to Technical Committee AW/6, Chemical analysis of meat and meat products, upon which the following bodies were represented: Association of Public Analysts British Meat Manufacturers Association British Poultry Meat Federation Lt

4、d. Department of Trade and Industry (Laboratory of the Government Chemist) Leatherhead Food Research Association Meat and Livestock Commission Ministry of Agriculture, Fisheries and Food National Federation of Meat and Food Traders Royal Society of Chemistry Worshipful Company of Butchers Amendments

5、 issued since publication Amd. No. Date CommentsBS4401-5:1996 BSI 03-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative reference 1 3 Definitions 1 4 Principle 1 5 Reagent and material 1 6 Apparatus 1 7 Sampling 1 8 Preparation of test sample 1

6、9 Procedure 2 10 Calculation 2 11 Precision 2 12 Test report 3 Annex A (informative) Bibliography 4 List of references Inside back coverBS4401-5:1996 ii BSI 03-1999 National foreword This Part of BS4401 has been prepared by Technical Committee AW/6. It is identical with ISO1444:1996 Meat and meat pr

7、oducts Determination of free fat content, published by the International Organization for Standardization (ISO) and in the preparation of which the United Kingdom played a full part. It is a revision of BS4401-5:1970 which is withdrawn and from which it differs principally in that automated extracti

8、on systems based on the soxhlet technique may be used instead of the classical soxhlet apparatus. ISO5725:1986, to which informative reference is made in the text, has been superseded by ISO5725-1:1994, ISO5725-2:1994, ISO5725-3:1994, ISO5725-4:1994 and ISO5725-6:1994 which are identical with BS ISO

9、5725 Accuracy (trueness and precision) of measurement methods and results, BS ISO5725-1:1994 General principles and definitions, BS ISO5725-2:1994 Basic method for the determination of repeatability and reproducibility of a standard measurement method, BS ISO5725-3:1994, Intermediate measures of the

10、 precision of a standard measurement method, BS ISO5725-4:1994 Basic method for the determination of the trueness of a standard measurement method, and BS ISO5725-6:1994 Use in practice of accuracy values. A British Standard does not purport to include all the necessary provisions of a contract. Use

11、rs of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding British Standard Normative ISO1442:1996 a BS4401 Methods of test for meat and me

12、at products Part3:1996 aDetermination of moisture content (Identical) Informative ISO3100-1:1991 BS5348 Methods for sampling meat and meat products Part1:1991 Taking primary samples (Identical) a In publication. Summary of pages This document comprises a front cover, an inside front cover, pages i a

13、nd ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.BS4401-5:1996 BSI 03-1999 1 1 Scope This International Standard specifies a

14、method for the determination of the free fat content of meat and meat products by means of extraction. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition

15、 indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid

16、International Standards. ISO1442:1996 1) , Meat and meat products Determination of moisture content (Reference method). 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 free fat content of meat and meat products mass of the fat extracted under the c

17、onditions specified in this International Standard divided by the mass of the test portion. The free fat content is expressed as a percentage by mass 3.2 test result the value of a characteristic obtained by carrying out a specified test method ISO5725-1 4 Principle Extraction, by means of n-hexane

18、or light petroleum, of the dried residue obtained in accordance with the method of determination of the moisture content specified in ISO1442. Removal of the solvent by evaporation, then drying and weighing of the extract. 5 Reagent and material 5.1 Extraction solvent, n-hexane or, alternatively, li

19、ght petroleum distilling between40C and60C, and having a bromine value less than1. For either solvent, the residue on complete evaporation shall not exceed 0,002g per100ml. 5.2 Boiling-chips 6 Apparatus Usual laboratory apparatus and, in particular, the following: 6.1 Homogenizing equipment, mechani

20、cal or electrical, capable of homogenizing the test sample. This includes a high-speed rotational cutter, or a mincer fitted with a plate with holes not exceeding4,5mm in diameter. 6.2 Extraction thimble, made of filter paper and defatted. 6.3 Cotton wool, defatted. 6.4 Extraction apparatus, continu

21、ous or semicontinuous, for example the Soxhlet type. NOTE 1Instead of the classical Soxhlet technique, the extraction procedure may also be performed with extraction systems capable of simultaneous extraction of a number of samples, such as Soxtec or other similar automated instruments. 6.5 Sand bat

22、h or water bath, electrically heated, or similar suitable apparatus. 6.6 Drying oven, electrically heated, capable of being maintained at103C2C. 6.7 Desiccator, containing an efficient desiccant,e.g.silica gel. 6.8 Analytical balance, capable of weighing to an accuracy of 0,001g. 7 Sampling It is im

23、portant that the laboratory receive a sample which is truly representative and 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 ISO3100-1. The mass of the laboratory sam

24、ple shall be not lessthan200g. Store the sample in such a way that deterioration and change in its composition are prevented. 8 Preparation of test sample 8.1 Homogenize the test sample with the appropriate equipment(6.1). Take care that the temperature of the sample material does not rise above25 C

25、. If a mincer is used, pass the sample at least twice through the equipment. 8.2 Fill a suitable airtight container with the prepared sample. Close the container and store in such way that deterioration and change in composition are prevented. Analyse the sample as soon as practicable, but always wi

26、thin24h of homogenization. 1) To be published. (Revision of ISO1442:1973BS4401-5:1996 2 BSI 03-1999 9 Procedure NOTE 2If it is required to check whether the repeatability requirement is met, carry out two single determinations in accordance with9.1 and9.2 under repeatability conditions. 9.1 Test por

27、tion Take a known mass of5 g to8 g, weighed to the nearest0,001 g (m o ) of the prepared sample and dry it by the procedure specified in ISO1442. If desired, the dried test portion from the determination of moisture content may be used for the determination of free fat. For reliable measurements, th

28、e lowest level of fat present in the test portion should be0,05 g. 9.2 Determination Dry the flask of the extraction apparatus(6.4), containing some boiling-chips(5.2), for1 h in the drying oven(6.6) set at103C. Allow the flask to cool to room temperature in the desiccator(6.7) and weigh to the near

29、est0,001 g (m 1 ). Transfer the dried test portion(9.1) quantitatively from the dish to the extraction thimble(6.2). Remove the last traces of the dried test portion from the dish, using cotton wool(6.3) moistened with the extraction solvent(5.2), and also transfer this cotton wool to the thimble. P

30、lace the thimble in the extraction tube of the apparatus. Pour the extraction solvent into the flask of the extraction apparatus; the amount of solvent shall be at least one and a half to two times the capacity of the extraction tube of the apparatus. Fit the flask to the extraction apparatus. Heat

31、the flask for at least6h on the sand bath or water bath (6.5), according to the extraction rate and the apparatus used. When a Soxtec or other similar automatic procedure is used, the heating period shall be at least2h. After extraction, take the flask containing the liquid from the extraction appar

32、atus and distil off the solvent using, for example, the sand bath or water bath. Evaporate the last traces of solvent using air blowing if desired. Dry the flask for1h in the oven(6.6) set at103 C and, after allowing it to cool to room temperature in the desiccator(6.7), weigh to the nearest0,001 g.

33、 Repeat the operations of heating, cooling and weighing until the results of two successive weighings, separated by1h of heating, do not differ by more than0,1% of the mass of the test portion (m 2 ). Verify completion of the extraction by taking a second extraction flask and extracting for a furthe

34、r period of1h with a fresh portion of the solvent. The increase in mass shall not exceed0,1% of the test portion. 10 Calculation Calculate the free fat content, w f , as a percentage by mass, using the following equation: where Report the result rounded to one decimal place. 11 Precision The precisi

35、on of the method has been established by an interlaboratory test (see reference 4), carried out in accordance with ISO5725 2) . For the values obtained for the repeatability limit, r, and the reproducibility limit, R, a probability level of95% holds. 11.1 Repeatability The absolute difference betwee

36、n 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, should not be greater than the repeatability limit r as calculated using the following equation: r=0,

37、05+0,06 whereis the mean of the two test results, expressed as a percentage by mass. 11.2 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, s

38、hould not be greater than the reproducibility limit R as calculated using the following equation: R=0,04+0,06 whereis the mean of the two test results, expressed as a percentage by mass. m 0 is the mass, in grams, of the test portion taken for drying; m 1 is the mass, in grams, of the extraction fla

39、sk with boiling chips; m 2 is the mass, in grams, of the flask and boiling chips with the fat, after drying. 2) ISO5725:1986 was used to obtain the precision data. This has now been cancelled and replaced by ISO5725-1:1994 and subsequent parts. wf m 2 m 1 () m 0 - 100 % = w f w f w f w fBS4401-5:199

40、6 BSI 03-1999 3 12 Test report The test report shall specify: the method in accordance with which sampling was carried out, if known; the method used; the test result(s) obtained; and if the repeatability has been checked, the final quoted result obtained. It shall also mention all operating details

41、 not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s). The test report shall include all information necessary for the complete identification of the sample.BS4401-5:1996 4 BSI 03-1999 Annex A (info

42、rmative) Bibliography 1 ISO3100-1:1991, Meat and meat products Sampling and preparation of test samples Part1: Sampling. 2 ISO5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. 3 ISO5725-1:1994, Accuracy (true

43、ness and precision) of measurement methods and results Part1: General principles and definitions. 4FOSTER, M.L. and SHARON, E.G. Soxtec fat analyzer for determination of total fat in meat: Collaborative Study. J. Assoc. Off. Anal. Chem., 75, 1992, pp. 288-292.BS4401-5:1996 BSI 03-1999 List of refere

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