1、June 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!,y$_“9860160www.din
2、.deDDIN EN ISO 21415-3Wheat and wheat flour Gluten content Part 3: Determination of dry gluten from wet gluten by an oven dryingmethod (ISO 21415-3:2006)English version of DIN EN ISO 21415-3:2007-06Weizen und Weizenmehl Glutengehalt Teil 3: Bestimmung des Trockenglutens aus Feuchtgluten mittelsOfent
3、rocknungsverfahren (ISO 21415-3:2006)Englische Fassung DIN EN ISO 21415-3:2007-06www.beuth.deDocument comprises 11 pages 09.07DIN EN ISO 21415-3:2007-06 2 National foreword This standard has been prepared by Technical Committee ISO/TC 34 “Agricultural food products” (Secretariat: AFNOR/ABNT France/B
4、razil), Subcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China). This standard has been published in accordance with a decision taken by CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR) to adopt, without alteration, International Standard ISO 21415-3 as a European Standard. The
5、responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Foodstuffs and Agricultural Products Standards Committee), Technical Committee Getreide und Getreideerzeugnisse. DIN EN ISO 21415 consists of the following parts, under the gene
6、ral 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 rapid
7、 drying method The DIN Standard corresponding to the International Standard referred to in 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 by a manual method
8、 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 21415-3 March 2007 ICS 67.060 English Version Wheat and wheat flour - Gluten content - Part 3: Determination of dry gluten from wet gluten by an oven drying method (ISO 21415-3:2006) Bl et farines de bl - Teneur en gluten - Partie 3: Dtermina
9、tion du gluten sec partir du gluten humide par une mthode de schage en tuve (ISO 21415-3:2006) Weizen und Weizenmehl - Glutengehalt - Teil 3: Bestimmung des Trockenglutens aus Feuchtgluten mittels Ofentrocknungsverfahren (ISO 21415-3:2006) This European Standard was approved by CEN on 25 February 20
10、07. 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 references concerning such national standards may be obtained
11、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 translation under the responsibility of a CEN member into its own language and notified to the CEN Management
12、Centre has the same status as the official 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, Po
13、land, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and
14、by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 21415-3:2007: EContents Page Foreword 1 Scope . 2 Normative references . 3 Terms and definitions. 4 Principle. 5 Apparatus 6 Procedure 6.1 Test portion . 6.2 Determination 7 Calculation and expression of results 7.1 Calculatio
15、n of the dry gluten content . 7.2 8 Precision 8.1 Interlaboratory tests . 8.2 Repeatability 8.3 Reproducibility 9 Test report . Annex A (informative) Results of an interlaboratory test. Bibliography . 2 EN ISO 21415-3:2007 (E) 55555566666789.34444Calculation of water content of the wet glutenForewor
16、d 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 21415-3:2007 by Technical Committee CEN/TC 338 “Cereal and cereal products”, the secretariat of
17、 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 conflicting national standards shall be withdrawn at the latest by September 2007. According to the CEN
18、/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, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, L
19、uxembourg, 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 as EN ISO 21415-3:2007 without any modifications. 3 EN ISO 21415-3:2007 (E) 1 Scope This part
20、of ISO 21415 specifies a method 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 th
21、e 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) applies. ISO 21415-1,
22、 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 definitions apply.
23、 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 this part of ISO 21415
24、or in ISO 21415-4 4 Principle A ball of wet gluten obtained under the conditions specified in ISO 21415-1 or ISO 21415-2 is dried then weighed. 4 EN ISO 21415-3:2007 (E) 5 Apparatus Usual laboratory apparatus and, in particular, the following. 5.1 Scalpel or knife. 5.2 Metal or glass plate, 5 cm 5 c
25、m. 5.3 Oven, capable of being maintained 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 b
26、y the method specified in ISO 21415-1 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. I
27、t 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 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 parall
28、el deep incisions in the partially 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
29、plus the dry gluten ball to the nearest 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 40dry10
30、0 %mmGm= where m4is the mass of the 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. 5 EN ISO 21415-3:2007 (E) It is necessary to know th
31、e 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 I
32、SO 712, is taken into account, the dry gluten 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
33、of water content of the wet gluten The water 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
34、test on the precision of the method are 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 th
35、e same method on identical 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 r = 0,6 g/100 g, starting from either the manual or the mechanical determination of wet gluten. 8.3 Reprod
36、ucibility The absolute difference 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 manu
37、al determination of wet gluten: R = 3,1 g/100 g; starting from the mechanical determination of wet gluten: R = 2,3 g/100 g. 6 EN ISO 21415-3:2007 (E) 9 Test report The test report shall specify: a) all information necessary for the complete identification of the sample; b) the sampling method used,
38、if known; c) the test method used, with reference 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 th
39、at occurred when performing the method, which 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. 7 EN ISO 21415-3:2007 (E) Annex A (informative) Results of an interlaboratory test An interlaboratory test
40、 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 L.) as grain; Sample C
41、: 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 A.1 and A.2. Table A.1 Precision
42、 data for dry gluten, starting from wet gluten obtained 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
43、variation of repeatability, % 3,49 2,45 1,33 2,11 1,29 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 Reproducibi
44、lity limit R (= 2,8 sR), g/100 g 1,88 4,19 4,69 3,04 2,09 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 Repeatab
45、ility 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 g 0,39 0,52 0,68 1,55 0,79 0,91 Coeffic
46、ient of variation of reproducibility, % 4,68 4,59 6,46 12,09 8,08 7,41 Reproducibility limit R (= 2,8 sR), g/100 g 1,08 1,45 1,91 4,34 2,20 2,55 8 EN ISO 21415-3:2007 (E) Bibliography 1 ISO 712, Cereals and cereal products Determination of moisture content Routine reference method 2 ISO 21415-4, Wheat and wheat flour Gluten content Part 4: Determination of dry gluten from wet gluten by a rapid drying method 9 EN ISO 21415-3:2007 (E)
