SIST EN ISO 21415-2:2008

SLOVENSKI STANDARD
SIST EN ISO 21415-2:2008
01-marec-2008
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Wheat and wheat flour - Gluten content - Part 2: Determination of wet gluten by
mechanical means (ISO 21415-2:2006)
Weizen und Weizenmehl - Glutengehalt - Teil 2: Bestimmung des Feuchtglutens durch
mechanische Verfahren (ISO 21415-2:2006)
Blé et farines de blé - Teneur en gluten - Partie 2: Détermination du gluten humide par
des moyens mécaniques (ISO 21415-2:2006)
Ta slovenski standard je istoveten z: EN ISO 21415-2:2008
ICS:
67.060
SIST EN ISO 21415-2:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD
EN ISO 21415-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2008
ICS 67.060

English Version
Wheat and wheat flour - Gluten content - Part 2: Determination
of wet gluten by mechanical means (ISO 21415-2:2006)
Blé et farines de blé - Teneur en gluten - Partie 2: Weizen und Weizenmehl - Glutengehalt - Teil 2:
Détermination du gluten humide par des moyens Bestimmung des Feuchtglutens durch mechanische
mécaniques (ISO 21415-2:2006) Verfahren (ISO 21415-2:2006)
This European Standard was approved by CEN on 15 December 2007.
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 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 Centre has the same status as the
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© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21415-2:2008: E
worldwide for CEN national Members.

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EN ISO 21415-2:2008 (E)






Foreword



The text of ISO 21415-2:2006 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 21415-2:2008 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 July 2008, and conflicting national
standards shall be withdrawn at the latest by July 2008.

Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any
or all such patent rights.
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, Estonia, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United
Kingdom.
Endorsement notice

The text of ISO 21415-2:2006 has been approved by CEN as EN ISO 21415-2:2008 without any
modifications.

2

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INTERNATIONAL ISO
STANDARD 21415-2
First edition
2006-11-15


Wheat and wheat flour — Gluten
content —
Part 2:
Determination of wet gluten
by mechanical means
Blé et farines de blé — Teneur en gluten —
Partie 2: Détermination du gluten humide par des moyens mécaniques





Reference number
ISO 21415-2:2006(E)
©
ISO 2006

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ISO 21415-2:2006(E)
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ii © ISO 2006 – All rights reserved

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ISO 21415-2:2006(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 1
5 Reagents. 2
6 Apparatus . 2
7 Sampling. 3
8 Preparation of test sample. 3
9 Procedure . 3
9.1 General. 3
9.2 Test portion . 3
9.3 Dough preparation. 3
9.4 Washing the dough. 4
9.5 Removal of excess water and weighing the wet gluten. 4
9.6 Number of determinations . 4
10 Calculation and expression of results. 5
11 Precision. 5
11.1 Interlaboratory tests . 5
11.2 Repeatability. 5
11.3 Reproducibility. 5
12 Test report . 6
Annex A (informative) Washing chamber and kneader of Glutomatic equipment, and the
centrifuge. 7
Annex B (normative) Preparation of ground wheat. 9
Annex C (informative) Results of an interlaboratory test. 10
Bibliography . 11

© ISO 2006 – All rights reserved iii

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ISO 21415-2:2006(E)
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 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
International 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
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 patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21415-2 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals
and pulses.
This first edition of ISO 21415-2 cancels and replaces ISO 7495:1990, which has been technically revised.
Together with ISO 21415-1:2006, it also cancels and replaces ISO 5531:1978.
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 from wet gluten by an oven drying method
— Part 4: Determination of dry gluten from wet gluten by a rapid drying method
iv © ISO 2006 – All rights reserved

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ISO 21415-2:2006(E)
Introduction
The alternative techniques specified in this part of ISO 21415 and in ISO 21415-1 for the isolation of wet
gluten (i.e. washing out by hand and mechanical washing out) do not usually give equivalent results. The
reason is that, for complete development of gluten structure it is necessary to rest the dough. Therefore, the
result obtained by hand washing is usually higher than that obtained by mechanical washing, mainly in the
case of wheat which has high gluten content. Consequently, the test report should always indicate the
technique used.

© ISO 2006 – All rights reserved v

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INTERNATIONAL STANDARD ISO 21415-2:2006(E)

Wheat and wheat flour — Gluten content —
Part 2:
Determination of wet gluten by mechanical means
1 Scope
This part of ISO 21415 specifies a method for the determination of the wet gluten content of wheat flour
(Triticum aestivum L. and Triticum durum Desf.) by mechanical means. This method is directly applicable to
flour. It is also applicable to semolina and wheat after grinding, if their particle size distribution meets the
specification given in Table B 1.
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 712, Cereals and cereal products — Determination of moisture content — Routine reference method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
wet gluten
visco-elastic substance, composed principally of two protein fractions (gliadin and glutenin) in hydrated form,
obtained as specified in this part of ISO 21415 or ISO 21415-1
3.2
ground wheat
product of small-scale milling of whole wheat which meets the particle size distribution shown in Table B.1.
3.3
semolina
coarsely milled wheat endosperm
3.4
flour
finely milled wheat endosperm with a particle size of less than 250 µm
4 Principle
Dough is prepared from a sample of flour or reground semolina, or ground wheat and a solution of sodium
chloride, in the chamber of the equipment. The wet gluten is separated by washing the dough with sodium
chloride solution, followed by removal of excess washing solution by centrifugation. The residue is weighed.
© ISO 2006 – All rights reserved 1

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ISO 21415-2:2006(E)
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized
water or water of equivalent purity.
5.1 Sodium chloride solution, 20 g/l.
Dissolve 200 g of sodium chloride (NaCl) in water then dilute it to 10 l. The temperature of the soluti
...