DIN EN ISO 21415-4-2007 Wheat and wheat flour - Gluten content - Part 4 Determination of dry gluten from wet gluten by a rapid drying method (ISO 21415-4 2006) German version EN IS.pdf

1、July 2007DEUTSCHE NORM English price group 9No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 67.060!,y4“9869917www.din.

2、deDDIN EN ISO 21415-4Wheat and wheat flour Gluten content Part 4: Determination of dry gluten from wet gluten by a rapid dryingmethod (ISO 21415-4:2006)English version of DIN EN ISO 21415-4:2007-07Weizen und Weizenmehl Glutengehalt Teil 4: Bestimmung des Trockenglutens aus Feuchtgluten mittelsSchnel

3、ltrocknungsverfahren (ISO 21415-4:2006)Englische Fassung DIN EN ISO 21415-4:2007-07www.beuth.deDocument comprises 11 pages09.07DIN EN ISO 21415-4:2007-07 2 National foreword This standard has been prepared by Technical Committee ISO/TC 34 “Food products” (Secretariat: AFNOR/ABNT, France, Brazil), Su

4、bcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China), in collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France). Based on the results of the unique acceptance procedure, ISO 21415-4:2006 has been adopted as European Standard EN ISO 21415

5、-4:2007. The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und land-wirtschaftliche Produkte (Foodstuffs and Agricultural Products Standards Committee), Technical Committee Getreide und Getreideerzeugnisse. ISO 21415 consists of the following parts, under t

6、he general title Wheat and wheat flour Gluten content: Part 1: Determination of wet gluten by a manual method Part 2: Determination of wet gluten by mechanical means Part 3: Determination of dry gluten from wet gluten by an oven drying method Part 4: Determination of dry gluten from wet gluten by a

7、rapid drying method The DIN Standard corresponding to the International Standard referred to in clause 2 of the EN is as follows: ISO 21415-1 DIN EN ISO 21415-1 National Annex NA (informative) Bibliography DIN EN ISO 21415-1, Wheat and wheat flour Gluten content Part 1: Determination of wet gluten b

8、y a manual method EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 21415-4March 2007ICS 67.060English VersionWheat and wheat flour - Gluten content - Part 4: Determinationof dry gluten from wet gluten by a rapid drying methodBl et farines de bl - Teneur en gluten - Partie 4:Dtermination du glut

9、en sec partir du gluten humide parune mthode de schage rapide (ISO 21415-4:2006)Weizen und Weizenmehl - Glutengehalt - Teil 4:Bestimmung des Trockenglutens aus Feuchtgluten mittelsSchnelltrocknungsverfahren (ISO 21415-4:2006)This European Standard was approved by CEN on 25 February 2007.CEN members

10、are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to

11、the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same

12、status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania

13、, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldw

14、ide for CEN national Members.Ref. No. EN ISO 21415-4:2007: E(ISO 21415-4:2006)EN ISO 21415-4:2006 (E) Contents Page Foreword. 3 1 Scope . 4 2 Normative references . 4 3 Terms and definitions 4 4 Principle. 4 5 Apparatus 5 6 Procedure 5 6.1 Preparation of the drying plates 5 6.2 Drying wet gluten 5 7

15、 Calculation and expression of results 5 7.1 Calculation of the dry gluten content . 5 7.2 Calculation of water content of the wet gluten 6 8 Precision 6 8.1 Interlaboratory tests . 6 8.2 Repeatability 6 8.3 Reproducibility 6 9 Test report . 6 Annex A (normative) Electrically heated drying plates 7

16、Annex B (informative) Results of an interlaboratory test. 8 Bibliography . 9 2 EN ISO 21415-4:2006 (E) Foreword The text of ISO 21415-4:2006 has been prepared by Technical Committee ISO/TC 34 “Agricultural food products” of the International Organization for Standardization (ISO) and has been taken

17、over as EN ISO 21415-4:2007 by Technical Committee CEN/TC 338 “Cereal and cereal products”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 200

18、7, and conflicting national standards shall be withdrawn at the latest by September 2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republ

19、ic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 21415-4:2006 has been

20、approved by CEN as EN ISO 21415-4:2007 without any modifications. 3 1 Scope This part of ISO 21415 specifies a rapid method for the determination of the dry gluten content from wet gluten obtained as specified in either ISO 21415-1 or ISO 21415-2. The method can also be used to determine the moistur

21、e content of the wet gluten. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applie

22、s. ISO 21415-1, Wheat and wheat flour Gluten content Part 1: Determination of wet gluten by a manual method ISO 21415-2, Wheat and wheat flour Gluten content Part 2: Determination of wet gluten by mechanical means 3 Terms and definitions For the purposes of this document, the following terms and def

23、initions apply. 3.1 wet gluten visco-elastic substance, composed principally of two protein fractions (gliadin and glutenin) in a hydrated form, obtained as specified in ISO 21415-1 or ISO 21415-2 3.2 dry gluten residue obtained from wet gluten dried according to the conditions specified in ISO 2141

24、5-3 or in this part of ISO 21415 4 Principle A ball of wet gluten obtained under the conditions specified in ISO 21415-1 or ISO 21415-2 is dried then weighed. EN ISO 21415-4:2006 (E) 4 5 Apparatus Usual laboratory apparatus and, in particular, the following. 5.1 Electrically heated drying plates, ma

25、de up of two plates coated with anti-adhesion material and heated by resistance coils to reach a working temperature of 150 C to 200 C (see Annex A). 5.2 Balance, capable of weighing to the nearest 0,01 g. 6 Procedure 6.1 Preparation of the drying plates Allow the drying plates (5.1) to reach operat

26、ing temperature by running one drying cycle prior to commencing the test. 6.2 Drying wet gluten Take a ball of wet gluten obtained by the method specified in ISO 21415-1 or ISO 21415-2, from which most of the washing solution has been eliminated and which has been weighed to the nearest 0,01 g (m7).

27、 Place it between the prewarmed drying plates (5.1) for 300 s 5 s. Remove the dried gluten from the drying plates and weigh to the nearest 0,01 g (m6). 7 Calculation and expression of results 7.1 Calculation of the dry gluten content The dry gluten content (Gdry), expressed as a mass fraction, in pe

28、rcent, of the original sample (wheat flour, reground semolina or ground wheat) is equal to 6dry100 %mGm= where m6is the mass of dry gluten, in grams; m is the mass, in grams, of the portion of the original sample of dough taken for determination of the wet gluten content. It is necessary to know the

29、 mass of the original sample (m) from which the wet gluten was extracted. It should be noted that in the case of the manual washing out procedure this is not equal to the mass of the test portion of the original sample. If the moisture content of the original sample, determined in accordance with IS

30、O 712, is taken into account, the dry gluten content on a dry matter basis (Gdm), in percent, is equal to 6dm100100 %(100 )mGmw=where w is the moisture content of the original sample, as a mass fraction in percent. Take as the result the arithmetic mean of two determinations. EN ISO 21415-4:2006 (E)

31、 5 7.2 Calculation of water content of the wet gluten The water content of the wet gluten (wG), expressed as mass fraction in percent, is equal to 76G7100 %mmwm= where m7is the mass of wet gluten, in grams. 8 Precision 8.1 Interlaboratory test Details of an interlaboratory test on the precision of t

32、he method are summarized in Annex B. The values derived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given. 8.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical

33、 test material in the same laboratory by the same operator using the same equipment within a short interval of time, will in not more than 5 % of cases be greater than 0,6 g/100 g, starting from either the manual or the mechanical determination of wet gluten. 8.3 Reproducibility The absolute differe

34、nce between two single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than the values given below: starting from the manual determination of wet gluten

35、: R = 4,1 g/100 g; starting from the mechanical determination of wet gluten: R = 2,0 g/100 g. 9 Test report The test report shall specify: a) all information necessary for the complete identification of the sample; b) the sampling method used, if known; c) the test method used, with reference to thi

36、s part of ISO 21415 and reference to that part of ISO 21415 which was used for the determination of wet gluten; d) all operating details not specified in this part of ISO 21415, or regarded as optional, together with details of any incidents that occurred when performing the method, which may have i

37、nfluenced the test result(s); e) the test result(s) obtained; f) if the repeatability has been checked, the final quoted result obtained. EN ISO 21415-4:2006 (E) 6 Annex A (normative) Electrically heated drying plates EN ISO 21415-4:2006 (E) 7 Annex B (informative) Results of an interlaboratory test

38、 The interlaboratory test involving 21 laboratories in 7 countries was organized by the CONCORDIA Warehouse Ltd., Grain Control Laboratory, Budapest (Hungary) in 2004. It was carried out on the following six samples: Sample A: wheat (Triticum aestivum L.) as grain; Sample B: wheat (Triticum aestivum

39、 L.) as grain; Sample C: wheat (Triticum durum Desf.) as grain; Sample D: durum wheat semolina; Sample E: wheat flour; Sample F: wheat flour. The results obtained were subjected to statistical analysis in accordance with ISO 5725-1 and ISO 5725-2 to give the precision data shown in Tables B.1 and B.

40、2. Table B.1 Precision data for dry gluten, starting from wet gluten obtained by ISO 21415-1 Samples A B C D E F Number of laboratories after eliminating outliers 6 6 6 6 5 5 Mean value, g/100 g 8,38 11,04 10,34 12,54 9,65 12,03 Repeatability standard deviation, sr, g/100 g 0,18 0,20 0,36 0,25 0,26

41、0,12 Coefficient of variation of repeatability, % 2,11 1,82 3,46 1,96 2,72 1,02 Repeatability limit r (= 2,8 sr), g/100 g 0,49 0,56 1,00 0,69 0,74 0,34 Reproducibility standard deviation, sR, g/100 g 1,01 1,24 1,32 2,71 0,86 1,57 Coefficient of variation of reproducibility, % 12,11 11,26 12,77 21,65

42、 8,96 13,09 Reproducibility limit R (= 2,8 sR), g/100 g 2,84 3,48 3,70 7,60 2,42 4,41 Table B.2 Precision data for dry gluten, starting from wet gluten obtained by ISO 21415-2 Samples A B C D E F Number of laboratories after eliminating outliers 6 7 7 8 6 6 Mean value, g/100 g 8,47 11,37 10,76 13,04

43、 9,18 11,69 Repeatability standard deviation, sr, g/100 g 0,18 0,18 0,19 0,44 0,13 0,14 Coefficient of variation of repeatability, % 2,12 1,55 1,73 3,35 1,44 1,18 Repeatability limit r (= 2,8 sr), g/100 g 0,50 0,49 0,52 1,22 0,37 0,39 Reproducibility standard deviation, sR, g/100 g 0,46 0,74 0,65 1,

44、74 0,20 0,42 Coefficient of variation of reproducibility, % 5,48 6,48 6,07 13,38 2,19 3,58 Reproducibility limit R (= 2,8 sR), g/100 g 1,30 2,06 1,83 4,89 0,56 1,17 EN ISO 21415-4:2006 (E) 8 Bibliography 1 ISO 712, Cereals and cereal products Determination of moisture content Routine reference method 2 ISO 21415-3, Wheat and wheat flour Gluten content Part 3: Determination of dry gluten from wet gluten by an oven drying method EN ISO 21415-4:2006 (E) 9