1、DEUTSCHE NORM October 1994 c G c 5 E 2 c U .t ; 2 i C c C c ? a f C * C f 1 c T c 0 f 2 L T n “ “ * f F z Q r * Starches, native or modified Determination of total fat content (IS0 3947 : 1977) Enalish version of DIN EN IS0 3947 DIN I EN IS0 3947 This standard incorporates the English version of Is0
2、 3947. ICs 67.180.20 Supersedes DIN 10382, Descriptors: Starch, carbohydrate, fat content, testing. Strke, nativ oder modifiziert; Bestimmung des Gesamtfettgehaltes (IS0 3947 : 1977) July 1981 edition. European Standard EN IS0 3947: 1994 has the status of a DIN Standard. A comma is used as the decim
3、al marker. National foreword This standard has been published in accordance with a decision taken by CEN/BT to adopt, without alteration, Interna- tional Standard IS0 3947 as a European Standard. The responsible German body involved in its preparation was the Norrnenausschu Lebensmittel und landwirt
4、schaffliche Produkte (Foodstuffs and Agricultural Products Standards Committee). Amendments DIN 10382, July 1981 edition, has been superseded by the specifications of EN IS0 3947, which is identical to IS0 3947. Previous edition DIN 10382: 1981-07. International Patent Classification A 23 L 001/0522
5、 G O1 N 033/10 EN comprises 4 pages. uth Verlag GmbH, Berlin, has the exclusive right of sale for German Standards(D1N-Normen). DIN EN IS0 394 7 Eng/. Price group 04.95 Sales No. i 106 EUROPEAN STANDARD NORME EUROPENNE EUROPAISCHE NORM EN IS0 3947 August 1994 UDC 664.2 : 543.85 Descriptors: Starch,
6、carbohydrate, fat content, testing. English version Starches, native or modified (IS0 3947 : 1977) Determination of total fat content Amidons et fcules, natifs ou trans- forms; dtermination de la teneur en matires grasses totales (IS0 3947: 1977) Strke, nativ oder modifiziert; Bestim- mung des Gesam
7、tfettgehaltes (IS0 3947: 1977) This European Standard was approved by CEN on 1994-08-22 and is identical to the IS0 Standard as referred to. CEN members are bound to comply with the CENKENELEC Intemal Regulations which stipu- late the conditions for giving this European Standard the status of a nati
8、onal standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in an
9、y other language made by translation under the responsibility of a CEN member 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, Icel
10、and, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. GEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, 8-1050 Brussels O 1994. Copyright reserved
11、to all CEN members. Ref. NO. EN IS0 3947: 1994 E Page 2 EN IS0 3947 : 1994 Foreword International Standard IS0 3947:1977 Starches, native or modified; determination of total fat content was submitted for Formal Vote and approved by CEN/BT as EN ISO3947: 1994 without any modifications. This European
12、Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by February 1995 at the latest. In accordance with the CENEENELEC Internal Regulations, the following countries are bound to implemen
13、t this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of the International Standard IS0 3947: 1977 was approved by CEN as a
14、European Standard without any modifica- tion. Page 3 EN IS0 3947 : 1994 6 APPARATUS Glass apparatus should preferably be fitted with ground glass joints. Ordinary laboratory apparatus and in particular 6.1 Efficient extractor, for example Soxhlet or Twisselmann or other suitable type. 1 This Interna
15、tional Standard specifies a method for the determination of the total fat content of starches, native or modified, of which the expected total fat content is less than 1,5 % (mim). SCOPE AND FIELD OF APPLICATION 2 REFERENCE IS0 5808, Starch derivatives and by-products - Deter- mination of “extractab
16、le“ far content. ) 3 DEFINITION total fat content: The conditions described in the residue obtained under procedure and expressed the 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, inc
17、luding the total fat, by cooling. Separation by filtration, drying and isolation of the total fat by solvent extraction. 5 REAGENTS Use distilled water or water of at least equivalent purity. 5.1 Solvent : n-hexane or light petroleum (boiling range 40 to 60 “C) or carbon tetrachloride. (These solven
18、ts, especially the carbon tetrachloride, must be handled with care owing to their toxicity.) The residue on complete evaporation shall not exceed 0,001 g/100 ml. 5.2 Hydrochloric acid, p20 1,18 g/ml. 5.3 Iodine, 0,001 N solution. 6.2 Extraction flask, suitable for attaching to the lower end of the e
19、xtractor (6.1 1. 6.3 Filter paper discs, pore diameter lOpm, free from matter soluble in the solvent used (5.1). 6.4 Paper extraction thimble, suitable for use in the extractor (6.1), and free from matter soluble in the solvent used (5.1 ). 6.5 Cotton wool, free from matter soluble in the solvent us
20、ed (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. NOTE - An assembly of multiple extraction Iinits with individual electrical regulation may be used. 6.8
21、Water bath, at a temperature of 15 to 25 OC. 6.9 Boiling water bath. 6.10 Oven, capable of being controlled at 50 +- 1 “C. 6.11 Vacuum oven, capable of being controlled at 100 f 1 Oc. 6.12 Beaker, of capacity 600 mi. 6.13 Desiccator, containing an efficient desiccant. 5.4 Methyl orange, 2 g/l aqueou
22、s solution. 6.14 Analytical balance. i) In preparation. Page 4 EN IS0 3947 : 1994 7 PROCEDURE 7.1 hparaton of rho test sample Mix the laboratory sample well. 7.2 Toitportion Weigh, to the nearest 0.1 g, 25 to 50 g of the test sample (7.1) according to the expected total fat content, transfer to the
23、beaker (6.1 2) and suspend in 1 O0 ml of water. 7.3 Hydmlyrir Mix 100 ml of the hydrochloric acid (5.2) with 200 ml 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 for 5 min. Check that the mixture is free from star
24、ch, by transferring 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 in 7.4. If a blue colour develops, continue boiling the mixture, checking frequently to ensure that the solution is free f
25、rom starch, using the procedure in the previous paragraph. When the mixture is free from starch, proceed as in 7.4. 7.4 soparation of msidud product, Place the beaker and its contents in the water bath (6.81 for 30 min. Stir from time to time in order to ensure an even temperature and to precipitate
26、 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 ambient temperature until t
27、he 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 for 3 h in the oven (6.101, controlled at 50 f 1 “C. 7.5 Extraaionoftutalfat Place the filter paper and its contents in the ex
28、traction thimble (6.4). Close the neck of the thimble with cotton wool (6.5) and place it in the extractor (6.1). Place about 50 ml of the solvent (5.1) in the extraction flask (6.2). previously dried and weighed to the nearest 0.001 g. Attach the flask to the extractor (6.1 1, and place the condens
29、er (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). NOTE - Ensure that all connections of the extraction assembly are tight in order to avoid lors of solvent during the extraction. Control the heating so as
30、 to produce 150 to 200 drops of condensate per minute or 7 to 10 riphonings per hour, and continue the extraction for 3 h. 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 solven
31、t contained in the flask; place the latter for 1 h in the vacuum oven (6.1 I), controlled at 100 f 1 C. Transfer the flask to the desiccator (6.13). allow it to cool to ambient temperature and weigh it to the nearest 0,001 g. NOTE - Prolongad drying of the extract at high temperature may lead to a h
32、igh result due to oxidation of the fats. 7.6 Carry out two determinations on the same test sample (7.1 1. 8 EXPRESSION OF RESULTS 8.1 Mathod of calculation and formula The total fat content, expressed asa percentage by mass of the product as received, is given by the formula rn -rn mo x100 where mo
33、is the mass, in grams, of the test portion (7.2); rn, is the mass, in grams, of the empty extraction flask (see 7.5); m, is the mass, in grams, of the flask and the total fat after drying. Take as the result the arithmetic mean of two determi- nations if the conditions of repeatability (see 8.2) are
34、 satisfied. Otherwise, repeat the determinations. 8.2 Repeaability The difference between two determinations carried out simultaneously or in rapid succession by the same analyst on the same test sample shall not exceed 5 96 of the mean value. 9 TESTREPORT The test report shall indicate the method a
35、nd the solvent used and the result obtained. 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.
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