1、ICS 67.100.20; 67.200.10Bestimmung des Gesamtfettgehaltes von Butter und anderen Streichfetten Extraktionsverfahren mitberkritischem KohlenstoffdioxidIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout a
2、s the decimal marker.Ref. No. DIN 10480 : 2002-12English price group 06 Sales No. 010611.03DEUTSCHE NORM December 200210480 No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the ex
3、clusive right of sale for German Standards (DIN-Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Determination of total fat content of butter andother spreadable fats by extraction withsupercritical carbon dioxideC
4、ontinued on pages 2 and 3.ForewordThis standard has been prepared by Technical Committee Chemische und physikalische Milchuntersuchungof the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Foodstuffs and Agricultural Prod-ucts Standards Committee).1 ScopeThis standard specifies a rout
5、ine method of determining the total fat content of butter and other spreadablefats by extraction with supercritical carbon dioxide.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropria
6、te places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publicatio
7、n referred to applies.DIN EN ISO 707 Milk and milk products Guidance on sampling (ISO 707 : 1997)DIN EN ISO 3727-1 Butter Determination of moisture, non-fat solids and fat contents Part 1: Determi-nation of moisture content (reference method) (ISO 3727-1 : 2001)ISO 5725-1 : 1994 Accuracy (trueness a
8、nd precision) of measurement methods and results Part 1:General principles and definitionsISO 5725-2 : 1994 Accuracy (trueness and precision) of measurement method and results Part 2: Basicmethods for the determination of repeatability and reproducibility of a standard mea-surement methodPage 2DIN 1
9、0480 : 2002-123 ConceptTotal fatThe proportion by mass of total fat determined by the method specified in this standard.NOTE: The total fat content is reported in g per 100 g of sample material or as a percentage.4 PrincipleUsing the supercritical fluid extraction (SFE) method, the fat is extracted
10、with supercritical carbon dioxide (e.g.at 100 C and a pressure of 600 kPa) from the sample. The extract is collected in a glass container and the totalfat content is determined as the ratio of the mass of the extract to that of the initial sample.5 Reagents5.1 GeneralThe following analytical grade r
11、eagents shall be used.5.2 Kieselguhr.5.3 Commercial carbon dioxide, in cylinders with riser tube.5.4 Compressed air, oil- and water-free.5.5 Glass wool, dry and fat-free.6 ApparatusIn addition to standard laboratory equipment, the following shall be used.6.1 SFE analyser, fitted with a sample contai
12、ner with fine microfilter, a high-pressure seal and a fat collectingtube, designed for an extraction temperature of (100 t 5) C and a pressure of (600 t 10) kPa.6.2 Spatula.6.3 Filter (e.g. glass-fibre or paper filter (depending on the SFE analyser used).6.4 Analytical balance, capable of weighing t
13、o an accuracy of 0,1 mg.6.5 Ultrasonic cleaner.6.6 Microwave oven, capable of being maintained at 600 W, or drying oven, capable of being maintained at100 C.7 SamplingSee DIN EN ISO 707.8 Procedure8.1 Sample preparationSee DIN EN ISO 3727-1.8.2 Preparation of sample container and fat collection tube
14、Insert a filter into the lower part of a sample container and seal it with a cap. Then add about 2,5 g of kieselguhrusing a spatula.NOTE: Use an ultrasonic cleaner to clean the fine microfilter in the cap of the sample container.Fill the dry fat collection tube loosely with glass wool.8.3 AnalysisWe
15、igh, to an accuracy of 0,1 mg, about 1 g of sample material prepared as in subclause 8.1 on a filter paperand place it in the sample container prepared as in subclause 8.2. Then weigh the fat collection tube filled withglass wool and transfer its mass (m1) together with the mass of the previously we
16、ighed initial sample (m0) tothe SFE analyser. If necessary, prepare additional sample containers and fat collection tubes, treating them inthe same way.Page 3DIN 10480 : 2002-12Fit the fat collection tube prepared as in subclause 8.2 to the bottom of the fat outlet of the SFE analyser.Introduce the
17、sealed sample container into the SFE analyser and start the extraction by pressing the analysiskey. Analyse the sample in accordance with the manufacturers instructions.Then remove the fat collection tube and dry it to constant mass in a microwave oven (e.g. for four minutes at600 W) or in a drying
18、oven. After the tube has cooled to ambient temperature, reweigh it and transfer its mass(m2) to the SFE analyser.9 EvaluationCalculate the total fat content of the sample, wGF, as a percentage, using the following equation:m2 m1wGF= 100 (1)m0where:m0is the mass of the initial sample, in g;m1is the m
19、ass of the fat collection tube filled with glass wool, in g;m2is the mass of the fat collection tube containing the extracted total fat after drying, in g.Report the result to one decimal place.10 Precision10.1 GeneralThe precision data were determined in 2001 on butter, three-quarter-fat spread, ma
20、rgarine and half-fat mar-garine in a preliminary interlaboratory test involving eight laboratories, based on ISO 5725-1 and ISO 5725-2,as part of a pilot study.As part of its quality control procedures, any laboratory using this standard must ensure the maintenance ofthe precision data specified in
21、this clause and demonstrate this in a suitable way (e.g. by participating in qualitycontrol/laboratory performance interlaboratory tests and using reference materials).10.2 Repeatability limit(same operator, same equipment)The difference between two successive results obtained under repeatability co
22、nditions will not exceed therepeatability limit, r, in more than 5 % of cases on average. The following values were found for the repeatabilitylimit.Butter: r = 0,43% for an average total fat content of 82,15%Three-quarter-fat spread: r = 0,49% for an average total fat content of 60,27%Margarine: r
23、= 0,41% for an average total fat content of 80,08%Half-fat margarine: r = 0,41% for an average total fat content of 40,07%If the repeatability limit is exceeded, both results shall be regarded as suspect.10.3 Reproducibility limit(different operators, different equipment)The difference between two i
24、ndividual results obtained under reproducibility conditions will not exceed thereproducibility limit, R, in more than 5% of cases on average. The following values were found for the repro-ducibility limit.Butter: R = 0,60% for an average total fat content of 82,15%Three-quarter-fat spread: R = 0,58%
25、 for an average total fat content of 60,27%Margarine: R = 0,43% for an average total fat content of 80,08%Half-fat margarine: R = 0,44% for an average total fat content of 40,07%If the reproducibility limit is exceeded, both results shall be regarded as suspect.11 Test reportThe test report shall refer to this standard and include at least the following details:a) nature, origin and description of sample;b) sampling method and date;c) expression of result;d) date of testing;e) reasons for any deviation from this standard.
