EN ISO 21415-3-2007 en Wheat and wheat flour - Gluten content - Part 3 Determination of dry gluten from wet gluten by an oven drying method《小麦与小麦粉 面筋含量 第3部分 用烘箱烘干法测定湿面筋中的干面筋》.pdf

1、BRITISH STANDARDBS EN ISO 21415-3:2007Wheat and wheat flour Gluten content Part 3: Determination of dry gluten from wet gluten by an oven drying methodThe European Standard EN ISO 21415-3:2007 has the status of a British StandardICS 67.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g

2、44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 21415-3:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2007 BSI 2007ISBN 978 0

3、580 50584 3National forewordThis British Standard was published by BSI. It is the UK implementation of EN ISO 21415-3:2007. It is identical with ISO 21415-3:2006.The UK participation in its preparation was entrusted to Technical Committee AW/4, Cereals and pulses.A list of organizations represented

4、on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued

5、 since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 21415-3March 2007ICS 67.060English VersionWheat and wheat flour - Gluten content - Part 3: Determinationof dry gluten from wet gluten by an oven drying method (ISO21415-3:2006)Bl et farines de bl - Teneur e

6、n gluten - Partie 3:Dtermination du gluten sec partir du gluten humide parune mthode de schage en tuve (ISO 21415-3:2006)Weizen und Weizenmehl - Glutengehalt - Teil 3:Bestimmung des Trockenglutens aus Feuchtgluten mittelsOfentrocknung (ISO 21415-3:2006)This European Standard was approved by CEN on 2

7、5 February 2007.CEN members 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

8、 obtained on application to 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 Man

9、agement Centre has the same 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, Norw

10、ay, Poland, Portugal,Romania, 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

11、 by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 21415-3:2007: EForeword The text of ISO 21415-3:2006 has been prepared by Technical Committee ISO/TC 34 “Agricultural food products” of the International Organization for Standardization (ISO) and has been taken over as EN ISO

12、21415-3:2007 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 2007, and conflict

13、ing 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 Republic, Denmark, Es

14、tonia, 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 21415-3:2006 has been approved by CEN

15、 as EN ISO 21415-3:2007 without any modifications. EN ISO 21415-3:2007Reference numberISO 21415-3:2006(E)INTERNATIONAL STANDARD ISO21415-3First edition2006-05-01Wheat and wheat flour Gluten content Part 3: Determination of dry gluten from wet gluten by an oven drying method Bl et farines de bl Teneu

16、r en gluten Partie 3: Dtermination du gluten sec partir du gluten humide par une mthode de schage en tuve EN ISO 21415-3:2007ii iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 1 5 Apparatus 2 6 Procedure 2 6.1 Test portion . 2 6.2 Determina

17、tion 2 7 Calculation and expression of results 2 7.1 Calculation of the dry gluten content . 2 7.2 Calculation of water content of the wet gluten3 8 Precision 3 8.1 Interlaboratory tests . 3 8.2 Repeatability 3 8.3 Reproducibility 3 9 Test report . 4 Annex A (informative) Results of an interlaborato

18、ry test. 5 Bibliography . 6 EN ISO 21415-3:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each

19、 member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Internationa

20、l Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards

21、 adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of

22、 patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21415-3 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses. This first edition of ISO 21415-3, together with ISO 21415-4:2006, cancels and replaces IS

23、O 6645:1981, which has been technically revised. ISO 21415 consists of the following parts, under the 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

24、 from wet gluten by an oven drying method Part 4: Determination of dry gluten from wet gluten by a rapid drying method EN ISO 21415-3:20071Wheat and wheat flour Gluten content Part 3: Determination of dry gluten from wet gluten by an oven drying method 1 Scope This part of ISO 21415 specifies a meth

25、od for the determination of the dry gluten content from wet gluten obtained as specified in either ISO 21415-1 or ISO 21415-2. In this method, dry gluten is obtained from wet gluten by drying in an oven. The method can also be used to determine the moisture content of the wet gluten. 2 Normative ref

26、erences 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) applies. ISO 21415-1, Wheat and wheat flour Gluten

27、 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 definitions apply. 3.1 wet gluten visco-elastic

28、 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 this part of ISO 21415 or in ISO 21415-4 4 Principle

29、 A ball of wet gluten obtained under the conditions specified in ISO 21415-1 or ISO 21415-2 is dried then weighed. EN ISO 21415-3:20072 5 Apparatus Usual laboratory apparatus and, in particular, the following. 5.1 Scalpel or knife. 5.2 Metal or glass plate, 5 cm 5 cm. 5.3 Oven, capable of being main

30、tained at a temperature of 130 C 2 C. 5.4 Desiccator, provided with an efficient desiccant. 5.5 Balance, capable of weighing to the nearest 0,01 g. 6 Procedure 6.1 Test portion Weigh the plate (5.2) to the nearest 0,01 g (m0). Take the ball of wet gluten, obtained by the method specified in ISO 2141

31、5-1 or ISO 21415-2, from which most of the washing solution has been eliminated. Place it on the plate. Weigh the plate and wet gluten to the nearest 0,01 g (m5). It is necessary to know the original mass of wheat flour (m) from which the wet gluten was extracted. It should be noted that in the case

32、 of the manual washing out procedure, this is not equal to the mass of the test portion of wheat flour. 6.2 Determination Place the plate and test portion in the oven (5.3) set at 130 C, and leave for 2 h. Remove the plate from the oven and make three or four parallel deep incisions in the partially

33、 dried gluten using the scalpel or knife (5.1). Then replace it in the oven for a further 4 h, so that the total drying time is 6 h. Remove the plate and dry gluten and cool in the desiccator (5.4) to ambient temperature (approximately 30 min). Then weigh the plate plus the dry gluten ball to the ne

34、arest 0,01 g (m4). 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 percent, of the original sample (wheat flour, reground semolina or ground wheat), is equal to 40dry100 %mmGm= where m4is the mass of th

35、e plate and the dry gluten together, in grams; m0is the mass of the empty plate, 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. EN ISO 21415-3:20073It is necessary to know the mass of the original sample (m) from w

36、hich 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 ISO 712, is taken into account, the dry g

37、luten content on a dry matter basis (Gdm), in percent, is equal to 40dm100 ( )100 %(100 )mmGmw=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. 7.2 Calculation of water content of the wet gluten The w

38、ater content of the wet gluten (wG), expressed as mass fraction in percent, is equal to 54G50100 %mmwmm=where m5is the mass, in grams, of the plate and the test portion of wet gluten together. 8 Precision 8.1 Interlaboratory test Details of an interlaboratory test on the precision of the method are

39、summarized in Annex A. 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 test material

40、 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 r = 0,6 g/100 g, starting from either the manual or the mechanical determination of wet gluten. 8.3 Reproducibility The absolute difference betwee

41、n 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: R = 3,1

42、g/100 g; starting from the mechanical determination of wet gluten: R = 2,3 g/100 g. EN ISO 21415-3:20074 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 refer

43、ence to this 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

44、 may have influenced the test result(s); e) the test result(s) obtained; f) if the repeatability has been checked, the final quoted result obtained. EN ISO 21415-3:20075Annex A (informative) Results of an interlaboratory test An interlaboratory test involving 21 laboratories in 7 countries was organ

45、ized 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 L.) as grain; Sample C: wheat (Triticum durum Desf.) as grain; Sample D: du

46、rum 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 A.1 and A.2. Table A.1 Precision data for dry gluten, starting from wet gluten obtaine

47、d as in ISO 21415-1 Samples A B C D E F Number of laboratories after eliminating outliers 6 7 5 7 8 8 Mean value, g/100 g 8,15 11,45 9,66 12,10 9,49 12,21 Repeatability standard deviation, sr, g/100 g 0,28 0,28 0,13 0,26 0,12 0,14 Coefficient of variation of repeatability, % 3,49 2,45 1,33 2,11 1,29

48、 1,12 Repeatability limit r (= 2,8 sr), g/100 g 0,80 0,78 0,36 0,71 0,34 0,38 Reproducibility standard deviation, sR, g/100 g 0,67 1,49 1,68 1,09 0,75 0,92 Coefficient of variation of reproducibility, % 8,24 13,06 17,35 8,97 7,86 7,57 Reproducibility limit R (= 2,8 sR), g/100 g 1,88 4,19 4,69 3,04 2

49、,09 2,59 Table A.2 Precision data for dry gluten, starting from wet gluten obtained as in ISO 21415-2 Samples A B C D E F Number of laboratories after eliminating outliers 8 8 7 8 7 7 Mean value, g/100 g 8,28 11,29 10,58 12,83 9,75 12,29 Repeatability standard deviation, sr, g/100 g 0,19 0,20 0,26 0,26 0,13 0,25 Coefficient of variation of repeatability, % 2,35 1,76 2,42 2,01 1,32 2,00 Repeatability limit r (= 2,8 sr), g/100 g 0,55 0,56 0,72 0,72 0,36 0,69 Reproducibility standard deviation, sR, g/100