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1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXAYHAPOAHA(I OPTAHH3AUMII II0 CTAHAAPTkI3AWiH l ORGANIZATION INTERNATIONALE DE NORMALISATION Meat and meat products - Determination of total fat content First edition - 1973-04-15 UDC 637.51/.52 : 543.85 Ref. No. IS0 1443-1973
2、 (E) Descriptors : agricultural products, animal products, meat, chemical analysis, determination of content, fats. Price based on 2 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04
3、/25/2007 22:39:02 MDTNo reproduction or networking permitted without license from IHS -,-,- FOREWORD IS0 (the International Organization for Standardization) is a worldwide federation of national standards institutes (IS0 Member Bodies). The work of developing international Standards is carried out
4、through IS0 Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. Draft Interna
5、tional Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the IS0 Council. Prior to 1972, the results of the work of the Technical Committees were published as IS0 Recommendations; these documents are n
6、ow in the process of being transformed into International Standards. As part of this process, International Standard IS0 1443 replaces IS0 Recommendation R 1443-1970 drawn up by Technical Committee ISO/TC 34, Agricultural foodproducts. The Member Bodies of the following countries approved the Recomm
7、endation : Australia Hungary Bulgaria India Chile Iran Czechoslovakia Israel Egypt, Arab Rep. of Korea, Rep. of France Netherlands Germany Norway Poland Portugal Romania Spain Thai land Turkey United Kingdom The Member Body of the following Recommendation on technical grounds : country expressed dis
8、approval of the New Zealand 0 International Organization for Standardization, 1973 l Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:39:02 MDTNo reprodu
9、ction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 14434973 (E) Meat and meat products - Determination of total fat content 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a reference method for the determination of the total fat content of
10、 meat and meat products1 1. 2 REFERENCE IS0 . . . , Meat and meat products - Sampling.21 3 DEFINITION total fat of meat and meat products : The fat extracted under the operating conditions described. The total fat content is expressed as a percentage by mass. 4 PRINCIPLE Boiling of the test free the
11、 occluded the resulting mass, light petroleum, of portion with dilute hydrochloric acid to and bound lipid fractions, filtration of drying, and extraction with n-hexane or the fat retained on the filter. 5 REAGENTS All reagents shall be of a recognized analytical quality. Water shall be distilled wa
12、ter or water of at least equivalent purity. 5.1 Extraction solvent, n-hexane or, alternatively, light petroleum distilling between 40 and 60 C, and having a bromine value less than 1. For either solvent, the residue on complete evaporation shall not exceed 0,002 g per 100 ml. 5.2 Hydrochloric acid,
13、approximately 4 N solution. Dilute IOOml of concentrated hydrochloric acid (P20 = 1 ,I9 g/ml) with 200 ml of water and mix. 5.3 Blue litmus paper. 5.4 Boiling chips. 6 APPARATUS Usual laboratory equipment not otherwise specified, and the following items : 6.1 Mechanical meat mincer, laboratory size,
14、 fitted with a plate with holes of diameter not exceeding 4 mm. 6.2 Conical flask, capacity 250 ml. 6.3 Clock glass or Petri dish, diameter not less than 80 mm. 6.4 Extraction thimble, made of filter paper and defatted. 6.5 Cotton wool, defatted. 6.6 Extraction apparatus, continuous or semi-continuo
15、us, for example the Soxhlet type, with an extraction flask of about 150 ml capacity. 6.7 Sand bath or water bath, electrically heated or similar suitable apparatus. 6.8 Drying oven, electrically heated, capable of being controlled at 103 + 2 “C. 6.9 Desiccator, containing an efficient desiccant. 6.1
16、0 Analytical balance. 6.11 Fluted filter paper, qualitative, of medium speed. 7 SAMPLE 7.1 Start from a representative sample of at least 200 g taken according to IS0 . . . . 7.2 Store the sample in such a way that deterioration and change in composition are prevented. 1) The fat obtained cannot be
17、used for the determination of the characteristics of the fat. 2) In preparation. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:39:02 MDTNo reproduction or networking permitt
18、ed without license from IHS -,-,- IS0 14434973 (E) 8 PROCEDURE 8.1 Preparation of sample Render the sample uniform by passing it at least twice through the meat mincer (6.1) and mixing. Keep it in a completely filled airtight container and store in such a way that deterioration and change in composi
19、tion are prevented. Analyse the sample as soon as possible, but in any case within 24 h. 8.2 Test portion According to the expected fat content, weigh 3 to 5 g of the minced sample to the nearest 0,001 g into the 250 ml conical flask (6.2). 8.3 Determination Dry the flask of the extraction apparatus
20、 (6.6) containing some boiling chips (5.4), for 1 h at 103 + 2 “C in the drying oven (6.8). Allow the flask to cool to room temperature in the desiccator (6.9) and weigh to the nearest 0,001 g. Add to the test portion 50 ml of the hydrochloric acid (5.2) and cover the conical flask (6.2) with a smal
21、l watch glass. Heat the conical flask on an asbestos wire gauze by means of a gas burner Jntil the contents begin to boil. Continue boiling over a small flame for 1 h and shake occasionally. Add 150 ml of hot water. Moisten the fluted filter paper (6.11) held in a glass funnel with water, and pour t
22、he hot contents from the flask onto the filter. Wash the flask and the watch glass thoroughly three times with hot water and dry in the oven. Wash the filter with hot water until the washings do not affect the colour of the blue litmus paper (5.3). Put the filter paper on the clock glass or Petri di
23、sh (6.3) and dry for 1 h in the oven at 103 + 2 ?C. Allow to cool. Roll up the filter paper and insert it into the extraction thimble (6.4). Remove any traces of fat from the clock glass or the Petri dish, using cotton wool (6.5) moistened with the extraction solvent (5.1), and also transfer the cot
24、ton wool to the thimble. Place the thimble in the extraction apparatus. The filter paper shall be handled either with tongs that can be rinsed or with paper cover slips on the fingers. Pour the extraction solvent into the dried flask of the extraction apparatus. Wash the inside of the conical flask
25、used for the disintegration with hydrochloric acid, and the covering watch glass with a portion of the extraction solvent and add it to the extraction flask. The total solvent quantity shall be one and a half to two times the capacity of the extraction tube of the apparatus. Fit the flask to the ext
26、raction apparatus. Heat the extraction flask for 4 h on the sand bath, water bath or other apparatus (6.7). After extraction, take the fla sk contain ing the liquid from the extraction apparatus and d istil off the sol vent, using, for example, the sand bath or water bath. Evaporate the last traces
27、of the solvent on the water bath, using air blowing if desired. Dry the extraction flask for 1 h in the drying oven at 103 + 2 “C and, after allowing to cool to room temperature in the desiccator, weigh to the nearest 0,001 g. Repeat these operations until the results of two successive weighings do
28、not differ more than 0,l Y/o of the mass of the test portion. Verify the completion of the extraction by taking a second extraction flask and extracting for a further period of 1 h with a fresh portion of the solvent. The increase in mass shall not exceed 0,l % of the mass of the test portion. Carry
29、 out two determinations on the same prepared sample. 9 EXPRESSION OF RESULTS 9.1 Method of calculation and formula The total fat content of the sample, expressed as a percentage by mass, is equal to 100 (m2 -m,)X - MO where m0 is the mass, in grams, of the test portion; ml is the mass, in grams, of
30、the extraction flask with boiling chips; m2 is the mass, in grams, of the flask and boiling chips with the fat, after drying. Take as the result the arithmetic mean of the two determinations, if the requirement of 9.2 is satisfied. . Report the result rounded to one decimal place. 9.2 Repeatability
31、The difference between the results of two determinations carried out simultaneously or in rapid succession by the same analyst shall not be greater than 0,5 g of total fat per 100 g of sample. IO TEST REPORT The test report shall show the method used and the result obtained. It shall also mention an
32、y operating conditions not specified in this International Standard, or regarded as optional, as well as any circumstances that may have influenced the result. The report shall include all details required for complete identification of the sample. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 22:39:02 MDTNo reproduction or networking permitted without license from IHS -,-,-