1、BRITISH STANDARD BS EN ISO 3947:1994 Starches, native or modified Determination of total fat content The European Standard EN ISO3947:1994 has the status of a BritishStandard UDC 664.2:543.85BSENISO3947:1994 This BritishStandard was published under the authority ofthe Standards Board and comesinto e
2、ffect on 15December1994 BSI01-2000 The following BSI reference relates to the work on this standard: Draft announced in BSI News March1993 ISBN 0 580 23184 4 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, compr
3、ises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung
4、 e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges St
5、andardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation United Kingdom BritishStandards Institution Amendments issued since publication Amd. No.
6、 Date CommentsBSENISO3947:1994 BSI 01-2000 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 1 Scope and field of application 3 2 Reference 3 3 Definition 3 4 Principle 3 5 Reagents 3 6 Apparatus 3 7 Procedure 3 8 Expression of results 4 9 Test report 4BSEN
7、ISO3947:1994 ii BSI 01-2000 National foreword This BritishStandard has been prepared under the direction of the BSI Standards Board and is the English language version of EN ISO3947:1994 Starches, native or modified Determination of total fat content, published by the European Committee for Standard
8、ization (CEN). It is identical with ISO3947:1977 Starches, native or modified Determination of total fat content, published by the International Organization for Standardization (ISO). This BritishStandard has been produced to fulfil BSIs obligation to publish all approved European Standards but, be
9、cause of the absence of interest in the UK in the subject concerned, there has been no UK participation in the preparation of EN ISO3947. Any queries relating to the EN should be directed to BSI. A British Standard does not purport to include all the necessary provisions of a contract. Users of Brit
10、ish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theENISO title page, pages2 to 4 and a back cover. T
11、his standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO3947 August1994 UDC 664.2:543.85 Descriptors: Starches, chemical analysis, dete
12、rmination of content, fats English version Starches, native or modified Determination of total fat content (ISO3947:1977) Amidons et fcules, natifs ou transforms Dtermination de la teneur en matires grasses totales (ISO3947:1977) Strken, nativ oder modifiziert Bestimmung des Gesamtfettgehaltes (ISO3
13、947:1977) This European Standard was approved by CEN on1994-08-22. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
14、 references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. The European Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN memb
15、er into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Swed
16、en, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref.No.ENISO3947:1994EENISO3947:1994 BSI 01-2000 2 Foreword The
17、text of the International Standard ISO3947:1977 prepared by ISO/TC93, Starch, was submitted to the formal vote and was approved by CEN as EN ISO3947:1994 on1994-08-22 without any modifications. This European Standard shall be given the status of a national standard, either by publication of an ident
18、ical text or by endorsement, at the latest by February1995, and conflicting national standards shall be withdrawn at the latest by February1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finlan
19、d, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom.ENISO3947:1994 BSI 01-2000 3 1 Scope and field of application This International Standard specifies a method for the determination of the total fat content of st
20、arches, native or modified, of which the expected total fat content is less than1,5%(m/m). 2 Reference ISO5808, Starch derivatives and by-products Determination of “extractable” fat content 1) . 3 Definition total fat content the residue obtained under the conditions described in the procedure and e
21、xpressed as a percentage by mass of the product as received 4 Principle Hydrolysis of the product by boiling hydrochloric acid, and coagulation of the insoluble products, including the total fat, by cooling. Separation by filtration, drying and isolation of the total fat by solvent extraction. 5 Rea
22、gents Use distilled water or water of at least equivalent purity. 5.1 Solvent: n-hexane or light petroleum (boiling range40 to60 C) or carbon tetrachloride. (These solvents, especially the carbon tetrachloride, must be handled with care owing to their toxicity.) The residue on complete evaporation s
23、hall not exceed0,001g/100ml. 5.2 Hydrochloric acid, 201,18g/ml. 5.3 Iodine, 0,001Nsolution. 5.4 Methyl orange, 2g/l aqueous solution. 6 Apparatus Glass apparatus should preferably be fitted with ground glass joints. Ordinary laboratory apparatus and in particular 6.1 Efficient extractor, for example
24、 Soxhlet or Twisselmann or other suitable type. 6.2 Extraction flask, suitable for attaching to the lower end of the extractor(6.1). 6.3 Filter paper discs, pore diameter10m, free from matter soluble in the solvent used(5.1). 6.4 Paper extraction thimble, suitable for use in the extractor(6.1), and
25、free from matter soluble in the solvent used(5.1). 6.5 Cotton wool, free from matter soluble in the solvent used(5.1). 6.6 Efficient water-cooled reflux condenser, suitable for attaching to the upper end of the extractor(6.1). 6.7 Electrical heating device, fitted with a variable temperature control
26、. NOTEAn assembly of multiple extraction units with individual electrical regulation may be used. 6.8 Water bath, at a temperature of15 to25 C. 6.9 Boiling water bath 6.10 Oven, capable of being controlled at50 1 C. 6.11 Vacuum oven, capable of being controlled at100 1 C. 6.12 Beaker, of capacity600
27、ml. 6.13 Desiccator, containing an efficient desiccant. 6.14 Analytical balance 7 Procedure 7.1 Preparation of the test sample Mix the laboratory sample well. 7.2 Test portion Weigh, to the nearest0,1g,25to50g of the test sample(7.1) according to the expected total fat content, transfer to the beake
28、r(6.12) and suspend in100ml of water. 7.3 Hydrolysis Mix100ml of the hydrochloric acid(5.2) with200ml of water. Bring the solution to the boil and add to the test portion suspension(7.2). Heat the mixture just to boiling and maintain for5min. Check that the mixture is free from starch, by transferri
29、ng a few drops of the mixture to a test tube, cooling to ambient temperature and adding one drop of the iodine solution(5.3). If no colour develops, proceed as in7.4. 1) In preparation.ENISO3947:1994 4 BSI 01-2000 If a blue colour develops, continue boiling the mixture, checking frequently to ensure
30、 that the solution is free from starch, using the procedure in the previous paragraph. When the mixture is free from starch, proceed as in7.4. 7.4 Separation of residual products Place the beaker and its contents in the water bath(6.8) for30min. Stir from time to time in order to ensure an even temp
31、erature and to precipitate the fatty materials. Filter the mixture quantitatively through the filter paper(6.3). Remove the fatty materials adhering to the inside of the beaker using pieces of dry filter paper(6.3) and add these to the residue. Wash the residue and the filter paper with water at amb
32、ient temperature until the filtrate is neutral to the methyl orange indicator solution(5.4). Fold the filter paper containing the residue and pieces of filter paper, place on a watch-glass and dry for3h in the oven(6.10), controlled at50 1 C. 7.5 Extraction of total fat Place the filter paper and it
33、s contents in the extraction thimble(6.4). Close the neck of the thimble with cotton wool(6.5) and place it in the extractor(6.1). Place about50ml of the solvent(5.1) in the extraction flask(6.2), previously dried and weighed to the nearest0,001g. Attach the flask to the extractor(6.1), and place th
34、e condenser(6.6) on the top of the extractor. Place the whole assembly on the heating device(6.7), and turn on the cooling water to the condenser(6.6). NOTEEnsure that all connections of the extraction assembly are tight in order to avoid loss of solvent during the extraction. Control the heating so
35、 as to produce150 to200drops of condensate per minute or7 to10siphonings per hour, and continue the extraction for3h. Disconnect the flask containing the extracted fatty materials. Immerse the extraction flask and its contents in the boiling water bath(6.9) and distil off almost all the solvent cont
36、ained in the flask; place the latter for1h in the vacuum oven(6.11), controlled at100 1 C. Transfer the flask to the desiccator(6.13), allow it to cool to ambient temperature and weigh it to the nearest0,001g. NOTEProlonged drying of the extract at high temperature may lead to a high result due to o
37、xidation of the fats. 7.6 Carry out two determinations on the same test sample(7.1) 8 Expression of results 8.1 Method of calculation and formula The total fat content, expressed as a percentage by mass of the product as received, is given by the formula where m 0 is the mass, in grams, of the test
38、portion(7.2); m 1 is the mass, in grams, of the empty extraction flask(see7.5); m 2 is the mass, in grams, of the flask and the total fat after drying. Take as the result the arithmetic mean of two determinations if the conditions of repeatability(see8.2) are satisfied. Otherwise, repeat the determi
39、nations. 8.2 Repeatability The difference between two determinations carried out simultaneously or in rapid succession by the same analyst on the same test sample shall not exceed5% of the mean value. 9 Test report The test report shall indicate the method and the solvent used and the result obtaine
40、d. It shall also mention all details not specified in this International Standard or which are optional, as well as any possible incidents likely to have influenced the results. The test report shall give all the information necessary for complete identification of the sample. m 2 m 1 m 0 -100 blank
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