DIN EN ISO 21415-2-2016 Wheat and wheat flour - Gluten content - Part 2 Determination of wet gluten and gluten index by mechanical means (ISO 21415-2 2015) German version EN ISO 21.pdf

1、March 2016 English price group 13No part of this translation 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!%MV“2429951www.din.deDIN EN

2、 ISO 21415-2Wheat and wheat flour Gluten content Part 2: Determination of wet gluten and gluten index by mechanical means (ISO 21415-2:2015);English version EN ISO 21415-2:2015,English translation of DIN EN ISO 21415-2:2016-03Weizen und Weizenmehl Glutengehalt Teil 2: Bestimmung von Feuchtgluten und

3、 Glutenindex durch mechanische Verfahren (ISO 21415-2:2015);Englische Fassung EN ISO 21415-2:2015,Englische bersetzung von DIN EN ISO 21415-2:2016-03Bl et farines de bl Teneur en gluten Partie 2: Dtermination du gluten humide et du gluten index par des moyens mcaniques (ISO 21415-2:2015);Version ang

4、laise EN ISO 21415-2:2015,Traduction anglaise de DIN EN ISO 21415-2:2016-03SupersedesDIN EN ISO 21415-2:2008-04www.beuth.deDocument comprises 22 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.04.16 DIN EN ISO 21415-2:2016-03 2

5、 A comma is used as the decimal marker. National foreword This document (EN ISO 21415-2:2015) contains, unchanged, the International Standard ISO 21415-2:2015, which had been prepared by Technical Committee ISO/TC 34 “Food products” (Secretariat: France/Brazil), Subcommittee SC 4 “Cereals and pulses

6、” (Secretariat: China). Based on the results of parallel voting under the leadership of ISO/TC 34/SC 4, Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France) decided to adopt the International Standard as a European Standard. The responsible German body involved in

7、 its preparation was DIN-Normenausschuss Lebensmittel und landwirtschaftliche Produkte (DIN Standards Committee Food and Agricultural Products), Working Committee NA 057-05-06 AA Getreide und Getreideerzeugnisse. Amendments This standard differs from DIN EN ISO 21415-2:2008-04 as follows: a) the met

8、hod has been revised and brought in line with the state of the art; b) the standard contains precision data obtained from an international interlaboratory test carried out under French leadership in August 2010 to validate the method. Previous editions DIN EN ISO 21415-2: 2008-04 EUROPEAN STANDARD N

9、ORME EUROPENNE EUROPISCHE NORM EN ISO 21415-2 October 2015 ICS 67.060 Supersedes EN ISO 21415-2:2008English Version Wheat and wheat flour - Gluten content - Part 2: Determination of wet gluten and gluten index by mechanical means (ISO 21415-2:2015) Bl et farines de bl - Teneur en gluten - Partie 2:

10、Dtermination du gluten humide et du gluten index par des moyens mcaniques (ISO 21415-2:2015) Weizen und Weizenmehl - Glutengehalt - Teil 2: Bestimmung von Feuchtgluten und Glutenindex durch mechanische Verfahren (ISO 21415-2:2015) This European Standard was approved by CEN on 13 June 2015. CEN membe

11、rs 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 on applicatio

12、n to the CEN-CENELEC 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-CENELEC Manageme

13、nt Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, L

14、ithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17,

15、 B-1000 Brussels 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 21415-2:2015 EEuropean foreword 3Introduction 51 Scope . 62 Terms and definitions . 63 Principle 64 Reagents 65 Apparatus . 76 Sampling 87 Preparation of tes

16、t sample . 88 Procedure. 88.1 General . 88.2 Testing 88.3 Paste preparation 88.4 Paste washing . 98.4.1 Detection of starch . 98.4.2 Flour . 98.4.3 Ground wheat . 98.4.4 Special case . 98.5 Spinning and weighing the wet gluten . 98.6 Determining the gluten index 98.7 Number of measurements . 109 Cal

17、culations and record of results. 1010 Precision 1010.1 Interlaboratory tests . 1010.2 Repeatability 1110.3 Reproducibility 1110.4 Critical difference. 1110.4.1 Comparison of two sets of measurements in the same laboratory . 1110.4.2 Comparison of two sets of measurements in two laboratories 1211 Tes

18、t report 12Annex A (informative) Washing chamber and mill of the Glutomatic unit and centrifuge . 13Annex B (normative) Preparation of ground wheat 16Annex C (informative) Results of interlaboratory tests .17Bibliography .20Contents PageDIN EN ISO 21415-2:2016-03 EN ISO 21415 2:2015 (E)- 2Foreword 4

19、European foreword This document (EN ISO 21415-2:2015) has been prepared by Technical Committee ISO/TC 34 “Food products“ in collaboration with 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

20、national standard, either by publication of an identical text or by endorsement, at the latest by April 2016, and conflicting national standards shall be withdrawn at the latest by April 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of pate

21、nt rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 21415-2:2008. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this Euro

22、pean Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slo

23、venia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 21415-2:2015 has been approved by CEN as EN ISO 21415-2:2015 without any modification. DIN EN ISO 21415-2:2016-03 EN ISO 21415 2:2015 (E)- 3 ForewordISO (the International Organization for Standardiz

24、ation) 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 member body interested in a subject for which a technical committee has been established has the right to be

25、 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 International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to

26、 develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of th

27、e ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified dur

28、ing the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the mea

29、ning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 34,

30、 Food products, Subcommittee SC 4, Cereals and pulses.This second edition of ISO 21415-2 cancels and replaces the first edition (ISO 21415-2-2006) which has been technically revised.ISO 21415 consists of the following parts, under the general title Wheat and wheat flour Gluten content : Part 1: Dete

31、rmination of wet gluten by a manual method Part 2: Determination of wet gluten and gluten index by mechanical means Part 3: Determination of dry gluten from wet gluten by using an oven-drying method Part 4: Determination of dry gluten from wet gluten by a rapid drying methodDIN EN ISO 21415-2:2016-0

32、3 EN ISO 21415 2:2015 (E)- 4 IntroductionThe alternative techniques specified in this part of ISO 21415 and in ISO 21415-1 for isolation of wet gluten (i.e. manual extraction and mechanical extraction) do not generally yield equivalent results. The reason for this is that for full development of the

33、 gluten structure the dough needs to be allowed to rest. Hence, the result obtained by manual extraction is usually greater than that obtained by mechanical extraction, especially in the case of wheat with high gluten content. Therefore, the test report should always state the technique used.DIN EN

34、ISO 21415-2:2016-03 EN ISO 21415 2:2015 (E)- 5 1 ScopeThis part of ISO 21415 specifies a method for determining the content of wet gluten and the gluten index for wheat flours (Triticum aestivum L. and Triticum durum Desf.) by mechanical means. This method is directly applicable to flours. It also a

35、pplies to common and durum wheat after grinding, if their particular size distribution meets the specification given in Table B.1.2 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.2.1wet glutenviscoelastic substance consisting mainly of two protein f

36、ractions (gliadin and glutenin) in hydrated form, obtained in the way indicated in this part of ISO 21415 or in ISO 21415-12.2gluten indexproportion of wet gluten remaining on the sieve after centrifugationNote 1 to entry: The higher the index, the stronger the gluten is.2.3ground wheatresult of exp

37、erimental grinding of whole wheat with the granulometry cited in Table B.12.4flourfinely ground wheat endosperm with a granulometry of less than 250 m3 PrinciplePreparation of a paste from a sample of flour or of ground wheat and a sodium chloride solution in the equipments chamber; separation of th

38、e wet gluten by washing this paste with a sodium chloride solution, followed by removal of excess washing solution by centrifugation and weighing the residue. The gluten index is obtained after centrifuging to force the wet gluten through a special sieve. The percentage of wet gluten remaining on th

39、e sieve after centrifuging is defined as the gluten index.4 ReagentsUse only reagents of recognized analytical grade, unless otherwise specified and distilled or demineralized water, or water of equivalent purity.DIN EN ISO 21415-2:2016-03 EN ISO 21415 2:2015 (E)- 6 4.1 Sodium chloride solution, 20

40、g/l.Dissolve 200 g of sodium chloride (NaCl) in water, then dilute to 10 l. When using this, it is recommended that the temperature of the solution be 22C 2 C.It is advisable to prepare this solution specially every day.4.2 Solution of iodine/potassium iodide (Lugols solution).Dissolve 2,54 g of pot

41、assium iodide (KI) in water. Add 1,27 g of iodine (I2) to this solution and, when the reagents have completely dissolved, dilute to 100 ml with water.5 ApparatusUsual laboratory apparatus and, in particular, the following items.5.1 Automatic gluten separation unit 1), (single or double) consisting o

42、f a washing/mixing chamber, mill(s) (see Figures A.1 and A.2) and an electronically controlled distribution device for extracting the gluten.5.1.1 Mixing/washing chamber(s), fitted with replaceable chrome-plated sieve support(s) with polyester sieves with an 88 m mesh gap and polyamide sieves with a

43、n 840 m mesh gap.The distance between the milling hook and the chrome-plated sieve support shall be 0,7 mm 0,05 mm. This value should be checked with the calibrated thickness shims supplied.5.1.2 10 l plastic drum, to contain the sodium chloride solution (4.1) connected to the equipment by a plastic

44、 tube.5.1.3 Distribution system, consisting of a peristaltic pump allowing the sodium chloride solution (4.1) used for washing the gluten to be delivered at a constant rate of between 50 ml/min and 56 ml/min.For a detailed description of the unit and for detailed operating instructions, users of thi

45、s part of ISO 21415 should consult the leaflet of the maker of the equipment used.5.2 Dispenser, for the sodium chloride solution, permitting delivery of 3 ml to 10 ml with an accuracy of 0,1 ml.5.3 Centrifuge, capable of maintaining a rotational frequency of 6 000 5 per minute and producing a radia

46、l acceleration of 2 000 g, fitted with 2 perforated plates with holes of diameter 600 m and/or 2 receptacles 22 mm in diameter equipped with a grid containing 600 m holes, to determine the gluten index (cf. Figures A.3 and A.4).5.4 Balance, calibrated to 0,01 g.5.5 Stainless steel spatula.5.6 Beaker

47、s with 500 ml capacity (to catch the rinsing water).5.7 Stainless steel or plastic grippers.1) The Glutomatic unit (types 2100 and 2200) made by Perten Instruments AB (Sweden) is the mechanical device most widely used at present for this purpose. This information is given for the benefit of users of

48、 this part of ISO 21415 and in no way implies that ISO approves or recommends exclusive use of this device. Other equipment may also be used if it yields similar results to those of the Glutomatic unit or those of the method described in ISO 21415-1.DIN EN ISO 21415-2:2016-03 EN ISO 21415 2:2015 (E)- 7 5.8 Lab crusher, capable of producing a ground product with a g