Cereals and cereal products - Common wheat (Triticum aestivum L.) - Determination of alveograph properties of dough at constant hydration from commercial or test flours and test milling methodology (ISO 27971:2023)

This document specifies a method of determining, using an Alveograph, the rheological properties of different types of dough obtained from common wheat flour (Triticum aestivum L.) produced by industrial milling or laboratory milling.
It describes the Alveograph test and how to use a laboratory mill to produce flour in two stages:
—    stage 1: preparation of the wheat grain for milling to make it easier to separate the bran from the endosperm;
—    stage 2: the milling process, including breaking between three fluted rollers, reduction of particle size between two smooth rollers and the use of a centrifugal sieving machine to grade the products.

Getreide und Getreideerzeugnisse - Weichweizen (Triticum aestivum L.) - Bestimmung der Eigenschaften von Teig bei konstanter Flüssigkeitszufuhr zu handelsüblichen Mehlen oder Versuchsmehlen bei gleichen Versuchsmahlverfahren mittels Alveograph (ISO 27971:2023)

Dieses Dokument legt ein Verfahren zur Bestimmung der rheologischen Eigenschaften verschiedener Teigarten mittels eines Alveographen fest, die aus Mehl von Weichweizen (Triticum aestivum L.) erhalten wurden, das durch industrielles Vermahlen oder Laborvermahlung hergestellt wurde.
Es beschreibt das alveographische Prüfverfahren sowie die Art und Weise der Anwendung einer Labormühle zur Herstellung von Mehl in zwei Stufen:
   Stufe 1: Vorbereitung des Weizens (Korn) zum Vermahlen, damit die Kleie leichter vom Endosperm getrennt werden kann;
   Stufe 2: die Vermahlung, einschließlich der Schrotung zwischen drei Riffelwalzen, der Verringerung der Korngröße zwischen zwei Glattwalzen sowie der Verwendung einer Zentrifugalsiebmaschine zur Klassierung der Erzeugnisse.

Céréales et produits céréaliers - Blé tendre (Triticum aestivum L.) - Détermination des propriétés alvéographiques d'une pâte à hydratation constante de farine industrielle ou d'essai et méthodologie pour la mouture d'essai (ISO 27971:2023)

Le présent document spécifie une méthode de détermination, au moyen d’un alvéographe, des caractéristiques rhéologiques de différents types de pâtes obtenues à partir de farine de blé tendre (Triticum aestivum L.) issue de mouture industrielle ou de mouture d’essai.
Elle décrit l’essai à l’alvéographe et les conditions d’obtention de la farine au moyen d’un moulin de laboratoire en deux étapes:
—    étape 1: préparation du grain de blé en vue de la mouture, afin de faciliter la séparation du son et de l’amande;
—    étape 2: processus de mouture comprenant un broyage entre trois cylindres cannelés, une réduction de la taille des particules entre deux cylindres lisses et le classement des produits à l’aide d’une bluterie centrifuge.

Žito in proizvodi iz žita - Navadna pšenica (Triticum aestivum L.) - Določevanje alveografskih lastnosti testa pri stalnem dodajanju vode iz običajnih komercialnih ali preskusnih mok in preskus postopka mletja (ISO 27971:2023)

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Status
Published
Publication Date
27-Jun-2023
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
28-Jun-2023
Completion Date
28-Jun-2023

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SLOVENSKI STANDARD
SIST EN ISO 27971:2023
01-september-2023
Nadomešča:
SIST EN ISO 27971:2015
Žito in proizvodi iz žita - Navadna pšenica (Triticum aestivum L.) - Določevanje
alveografskih lastnosti testa pri stalnem dodajanju vode iz običajnih komercialnih
ali preskusnih mok in preskus postopka mletja (ISO 27971:2023)
Cereals and cereal products - Common wheat (Triticum aestivum L.) - Determination of
alveograph properties of dough at constant hydration from commercial or test flours and
test milling methodology (ISO 27971:2023)
Getreide und Getreideerzeugnisse - Weichweizen (Triticum aestivum L.) - Bestimmung
der Eigenschaften von Teig bei konstanter Flüssigkeitszufuhr zu handelsüblichen
Mehlen oder Versuchsmehlen bei gleichen Versuchsmahlverfahren mittels Alveograph
(ISO 27971:2023)
Céréales et produits céréaliers - Blé tendre (Triticum aestivum L.) - Détermination des
propriétés alvéographiques d'une pâte à hydratation constante de farine industrielle ou
d'essai et méthodologie pour la mouture d'essai (ISO 27971:2023)
Ta slovenski standard je istoveten z: EN ISO 27971:2023
ICS:
67.060 Žita, stročnice in proizvodi iz Cereals, pulses and derived
njih products
SIST EN ISO 27971:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 27971:2023

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SIST EN ISO 27971:2023


EN ISO 27971
EUROPEAN STANDARD

NORME EUROPÉENNE

June 2023
EUROPÄISCHE NORM
ICS 67.060 Supersedes EN ISO 27971:2015
English Version

Cereals and cereal products - Common wheat (Triticum
aestivum L.) - Determination of alveograph properties of
dough at constant hydration from commercial or test
flours and test milling methodology (ISO 27971:2023)
Céréales et produits céréaliers - Blé tendre (Triticum Getreide und Getreideerzeugnisse - Weichweizen
aestivum L.) - Détermination des propriétés (Triticum aestivum L.) - Bestimmung der
alvéographiques d'une pâte à hydratation constante de Eigenschaften von Teig bei konstanter
farine industrielle ou d'essai et méthodologie pour la Flüssigkeitszufuhr zu handelsüblichen Mehlen oder
mouture d'essai (ISO 27971:2023) Versuchsmehlen bei gleichen Versuchsmahlverfahren
mittels Alveograph (ISO 27971:2023)
This European Standard was approved by CEN on 4 May 2023.

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-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 Management
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 27971:2023 E
worldwide for CEN national Members.

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SIST EN ISO 27971:2023
EN ISO 27971:2023 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 27971:2023
EN ISO 27971:2023 (E)
European foreword
This document (EN ISO 27971:2023) 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 national standard, either by publication of an
identical text or by endorsement, at the latest by December 2023, and conflicting national standards
shall be withdrawn at the latest by December 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 27971:2015.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 27971:2023 has been approved by CEN as EN ISO 27971:2023 without any modification.

3

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SIST EN ISO 27971:2023

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SIST EN ISO 27971:2023
INTERNATIONAL ISO
STANDARD 27971
Third edition
2023-06
Cereals and cereal products —
Common wheat (Triticum aestivum
L.) — Determination of Alveograph
properties of dough at constant
hydration from commercial or test
flours and test milling methodology
Céréales et produits céréaliers — Blé tendre (Triticum aestivum
L.) — Détermination des propriétés alvéographiques d'une
pâte à hydratation constante de farine industrielle ou d'essai et
méthodologie pour la mouture d'essai
Reference number
ISO 27971:2023(E)
© ISO 2023

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SIST EN ISO 27971:2023
ISO 27971:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
ISO 27971:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 2
7 Sampling . 6
8 Preparation of the wheat for laboratory milling . 6
8.1 Cleaning the laboratory sample . 6
8.2 Test portion . 6
8.3 Wheat moisture content determination . 6
8.4 Wheat preparation . 6
8.4.1 General . 6
8.4.2 Wheat with initial moisture content between 13 % and 15 % (one-stage
moistening) . 7
8.4.3 Wheat with a moisture content less than 13 % (two-stage moistening) . 7
8.4.4 Wheat with a moisture content greater than 15 % (preliminary drying
followed by moistening, as described above) . 7
9 Laboratory milling .7
9.1 General . 7
9.2 Milling procedure . . 8
9.2.1 Breaking . 8
9.2.2 Reduction . 8
9.2.3 Flour homogenization . 8
9.2.4 Storage of the flour . 9
9.3 Expression of milling results . 9
10 Preparation and Alveograph test .9
10.1 Preliminary checks . 9
10.2 Preliminary operations . 10
10.3 Kneading . 12
10.4 Preparation of dough test pieces . 14
10.5 Alveograph test . 15
10.5.1 Initial preparation . .15
10.5.2 First operation: placing the patty on the lower plate .15
10.5.3 Second operation: biaxial extension . 17
10.6 Expression of Alveograph test results . 17
10.6.1 General . 17
10.6.2 Maximum pressure parameter, P . 18
10.6.3 Mean abscissa at rupture, L . 18
10.6.4 Swelling index, G . 18
10.6.5 Elasticity index, I . 19
e
10.6.6 Curve configuration ratio, P/L . 19
10.6.7 Deformation work, W . 19
11 Precision .19
11.1 Interlaboratory tests . 19
11.1.1 Commercial flour . 19
11.1.2 Flour obtained from laboratory milling . 19
11.2 Repeatability limits . 20
iii
© ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
ISO 27971:2023(E)
11.2.1 General .20
11.2.2 Commercial flour — Limits established by the interlaboratory test .20
11.2.3 Flour obtained from laboratory milling . 20
11.3 Reproducibility limits . 21
11.3.1 General . 21
11.3.2 Commercial flour — Limits established by the proficiency tests . 21
11.3.3 Flour obtained from laboratory milling . 22
11.4 Uncertainty . 22
12 Test report .22
Annex A (informative) Characteristics of the mill suitable for obtaining a laboratory milled
flour .23
Annex B (normative) Quantity of water to be added to wheat for conditioning.25
Annex C (informative) Sample milling sheet .26
Annex D (informative) Conversion table from L to G.28
Annex E (informative) Interlaboratory and proficiency test data for commercial flours .30
Annex F (informative) Interlaboratory data for laboratory milled flour .40
Annex G (informative) Routine maintenance instructions for the Alveograph .52
Annex H (informative) Assessment of proteolytic activity in wheat (T. aestivum L.) or flour .54
Bibliography .56
iv
  © ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
ISO 27971:2023(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.
The procedures used to 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 document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4,
Cereals and pulses, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 338, Cereal and cereal products, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 27971:2015), which has been technically
revised.
The main changes are as follows:
— the oldest instruments (before AlveoNG) have been removed;
— the latest instruments (AlveoPC and Alveolab) have been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
ISO 27971:2023(E)
Introduction
The end-use value of wheat is determined by a number of properties that are useful in the manufacture
of baked products such as bread, rusks and biscuits.
Such properties include the important viscoelastic (rheological) properties of dough formed as a result
of flour hydration and kneading. An Alveograph is used to study the main parameters by subjecting
a dough test piece to biaxial extension (producing a dough bubble) by inflating it with air, which is
similar to the deformation to which it is subjected during bread dough fermentation.
Recording the pressure generated inside the bubble throughout the deformation of the dough test piece
until it ruptures provides information on the following:
a) The resistance of the dough to deformation, or its stiffness. It is expressed by the maximum
pressure parameter, P.
b) The extensibility or the possibility of inflating the dough to form a bubble. It is expressed by the
mean of the abscissa value at rupture, L, converted to the swelling index, G.
c) The elasticity of the dough during biaxial extension. It is expressed by the elasticity index, I .
e
d) The work required to deform the dough bubble until it ruptures, or its strength, which is
proportional to the area of the Alveogram (sum of the pressures throughout the deformation
process). It is expressed by the parameter, W.
The P/L ratio is a measurement of the balance between stiffness and extensibility.
Alveographs are commonly used throughout the wheat and flour industry, for the following purposes:
— selecting and assessing different varieties of wheat and marketing batches of wheat;
— blending different batches of wheat or flour to produce a batch with given values for the Alveographic
criteria (W, P, and L) complying with the proportional laws of blending;
— assessing the proteolytic activity in wheat or flour to detect possible contamination (see Annex H
for more details).
Alveographs are used both on the upstream side of the industry for marketing, selecting and
assessing the different wheat varieties and on the downstream side throughout the baking industries
(see References [9], [11], [12] and [13]).
vi
  © ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
INTERNATIONAL STANDARD ISO 27971:2023(E)
Cereals and cereal products — Common wheat (Triticum
aestivum L.) — Determination of Alveograph properties of
dough at constant hydration from commercial or test flours
and test milling methodology
1 Scope
This document specifies a method of determining, using an Alveograph, the rheological properties
of different types of dough obtained from common wheat flour (Triticum aestivum L.) produced by
industrial milling or laboratory milling.
It describes the Alveograph test and how to use a laboratory mill to produce flour in two stages:
— stage 1: preparation of the wheat grain for milling to make it easier to separate the bran from the
endosperm;
— stage 2: the milling process, including breaking between three fluted rollers, reduction of particle
size between two smooth rollers and the use of a centrifugal sieving machine to grade the products.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 835, Laboratory glassware — Graduated pipettes
ISO 712, Cereals and cereal products — Determination of moisture content — Reference method
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 12099, Animal feeding stuffs, cereals and milled cereal products — Guidelines for the application of
near infrared spectrometry
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
The behaviour of dough obtained from a mixture of flour and salt water is evaluated during
deformation. A dough disk (patty) is subjected to a constant air flow. At first it withstands the pressure.
Subsequently, it inflates into a bubble, according to its extensibility, and ruptures. The change in the
dough is measured and recorded in the form of a curve called an “Alveogram”.
1
© ISO 2023 – All rights reserved

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SIST EN ISO 27971:2023
ISO 27971:2023(E)
5 Reagents
Unless otherwise specified, use only reagents of recognized analytical grade, and only distilled or
demineralized water or water of equivalent purity.
5.1 Sodium chloride solution, obtained by dissolving (25 ± 0,2) g of sodium chloride (NaCl) in water
and then making the volume up to 1 000 ml. This solution shall not be stored for more than 15 days and
its temperature shall be (20 ± 2) °C when used.
5.2 Refined vegetable oil, low in polyunsaturates, such as peanut oil. It is possible to use olive oil
[1]
if its acid value is less than 0,4 (determined in accordance with ISO 660 ). Store in a dark place in a
closed container and replace regularly (at least every three months).
Alternatively, liquid paraffin (also known as “soft petroleum paraffin”), with an acid value of less than
or equal to 0,05 and the lowest possible viscosity [maximum 60 mPa·s (60 cP) at 20 °C].
5.3 Cold degreasing agent, optimum safety.
6 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
6.1 Mechanical cleaner, fitted with sieves for wheat cleaning, in accordance with the manufacturer’s
instructions.
6.2 Conical or riffle sample divider.
6.3 Analytical balance, accurate to 0,01 g.
6.4 Glass burette, of 50 ml in capacity, graduated in 1 ml divisions.
1)
6.5 Rotary blender , for grain conditioning and flour homogenization, including the following
components:
6.5.1 Constant speed stirrer.
6.5.2 Two worm screws integral with the flask, possibly via the stopper (one for wheat preparation,
the other for flour homogenization).
6.5.3 Several wide-necked plastic flasks, 2 l capacity.
2)
6.6 Test mill (laboratory mill) , manually or automatically operated (see Annex A).
1) The CHOPIN Technologies MR2L rotary blender is an example of a suitable product available commercially. This
information is given for the convenience of users of this document and does not constitute an endorsement by ISO
of this product.
2) The CHOPIN Technologies Chopin-Dubois CD1 test mill is an example of a suitable product available commercially.
This information is given
...

SLOVENSKI STANDARD
oSIST prEN ISO 27971:2022
01-april-2022
Žito in proizvodi iz žita - Navadna pšenica (Triticum aestivum L.) - Določevanje
lastnosti testa iz običajnih komercialnih ali preskusnih mok z alveografom ob
stalnem dodajanju vode in s preskusom postopka mletja (ISO/DIS 27971:2022)
Cereals and cereal products - Common wheat (Triticum aestivum L.) - Determination of
alveograph properties of dough at constant hydration from commercial or test flours and
test milling methodology (ISO/DIS 27971:2022)
Getreide und Getreideerzeugnisse - Weizen (Triticum aestivum L.) - Bestimmung der
Eigenschaften von Teig bei konstanter Flüssigkeitszufuhr zu handelsüblichen Mehlen
oder Versuchsmehlen bei gleichen Versuchsmahlverfahren mittels Alveograph (ISO/DIS
27971:2022)
Céréales et produits céréaliers Blé tendre (Triticum aestivum L.) Détermination des
propriétés alvéographiques d'une pâte à hydratation constante de farine industrielle ou
d'essai et méthodologie pour la mouture d'essai (ISO/DIS 27971:2022)
Ta slovenski standard je istoveten z: prEN ISO 27971
ICS:
67.060 Žita, stročnice in proizvodi iz Cereals, pulses and derived
njih products
oSIST prEN ISO 27971:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 27971:2022

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oSIST prEN ISO 27971:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 27971
ISO/TC 34/SC 4 Secretariat: SAC
Voting begins on: Voting terminates on:
2022-02-09 2022-05-04
Cereals and cereal products — Common wheat (Triticum
aestivum L.) — Determination of alveograph properties of
dough at constant hydration from commercial or test flours
and test milling methodology
Céréales et produits céréaliers — Blé tendre (Triticum aestivum L.) — Détermination des propriétés
alvéographiques d'une pâte à hydratation constante de farine industrielle ou d'essai et méthodologie pour
la mouture d'essai
ICS: 67.060
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 27971:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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oSIST prEN ISO 27971:2022
© ISO 2021 – All rights reserved
ISO/DIS 27971:2022(E)
ISO/TC 34/SC 4
Date : 2021-09-20
ISO/DIS 27971:2021(E)
ISO/TC 34/SC 4
Secretariat: SAC
Cereals and cereal products — Common wheat (Triticum
aestivum L.) — Determination of alveograph properties of dough
at constant hydration from commercial or test flours and test
milling methodology
Céréales et produits céréaliers — Blé tendre (Triticum aestivum L.) — Détermination des propriétés
alvéographiques d'une pâte à hydratation constante de farine industrielle ou d'essai et méthodologie pour
la mouture d'essai

DIS stage

Warning for WDs and CDs
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to
COPYRIGHT PROTECTED DOCUMENT
change without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of
© ISO 2022
which they are aware and to provide supporting documentation.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2022 – All rights reserved

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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Contents
Foreword . v
Introduction. vi
1  Scope . 1
2  Normative references . 1
3  Principle . 1
4  Reagents . 1
5  Apparatus . 2
6  Sampling . 6
7  Preparation of the wheat for laboratory milling. . 7
7.1  Cleaning the laboratory sample . 7
7.2  Test portion . 7
7.3  Wheat moisture content determination . 7
7.4  Wheat prep aration . 7
7.4.1  General . 7
7.4.2  Wheat with initial moisture content between 13 % and 15 % (one-stage
moistening) . 7
7.4.3  Wheat with a moisture content less than 13 % (two-stage moistening) . 7
7.4.4  Wheat with a moisture content greater than 15 % (preliminary drying followed by
moistening, as described above) . 8
8  Laboratory milling . 8
8.1  General . 8
8.2  Milling procedure . 8
8.2.1  Breaking . 8
8.2.2  Reduction . 9
8.2.3  Flour homogenization . 9
8.2.4  Storage of the flour . 9
8.3  Expression of milling results . 10
9  Preparation and alveograph test . 10
9.1  Preliminary checks . 10
9.2  Preliminary operations . 11
9.3  Kneading . 13
9.4  Preparation of dough test pieces . 13
9.5  Alveograph test . 15
9.5.1  Initial preparation . 15
9.5.2  First operation: placing the patty on the lower plate . 16
9.5.3  Second operation: biaxial extension . 17
9.6  Expression of alveograph test results . 18
9.6.1  General . 18
9.6.2  Maximum pressure parameter, P . 18
9.6.3  Mean abscissa at rupture, L . 18
9.6.4  Swelling index, G . 19
9.6.5  Elasticity index, I . 19
e
9.6.6  Curve configuration ratio, P/L . 19
9.6.7  Deformation work, W . 19
10  Precision . 19
10.1  Interlaboratory tests . 19
10.2  Repeatability limits . 20
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
10.2.1  Commercial flour: limits established by the interlaboratory test . 20
10.2.2  Flour obtained from laboratory milling . 20
10.3  Reproducibility limits . 20
10.3.1  Commercial flour: Limits established by the proficiency tests . 21
10.3.2  Flour obtained from laboratory milling . 21
10.4  Uncertainty . 21
11  Test report . 21
Annex A (informative) Characteristics of the Chopin-Dubois CD1 mill . 22
A.1  Breaking . 22
A.2  Reduction . 22
A.3  Sieve material . 22
A.4  Milling . 22
A.5  Break performance indicator . 23
A.6  Reduction performance indicator . 23
A.7  Maintenance operations . 23
Annex B (normative) Quantity of water to be added to wheat for conditioning . 24
Annex C (informative) Sample milling sheet . 25
Annex D (informative) Conversion table from L to G . 26
Annex E (informative) Interlaboratory and proficiency test data for commercial flours . 28
Annex F (informative) Interlaboratory data for laboratory milled flour . 37
Annex G (informative) Routine maintenance instructions for the Alveograph . 51
G.1  Before every test . 51
G.2  Every day . 51
G.3  Every week . 51
G.4  Every month . 51
G.5  Every year . 51
Annex H (informative) Assessment of proteolytic activity in wheat (T. aestivum L.) or
flour . 53
H.1  General . 53
H.2  Principle . 53
H.3  Reagents . 53
H.4  Apparatus . 53
H.5  Sampling and sample preparation . 53
H.6  Preparation and alveograph test . 53
Bibliography . 55
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(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.
The procedures used to 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 the 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 during 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 voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL:
www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 34, Food products, Subcommittee SC 4, Cereals
and pulse.
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Introduction
The end-use value of wheat is determined by a number of properties that are useful in the manufacture
of baked products such as bread, rusks, and biscuits.
Such properties include the important viscoelastic (rheological) properties of dough formed as a result
of flour hydration and kneading. An Alveograph is used to study the main parameters by subjecting a
dough test piece to biaxial extension (producing a dough bubble) by inflating it with air, which is similar
to the deformation to which it is subjected during bread dough fermentation.
Recording the pressure generated inside the bubble throughout the deformation of the dough test piece
until it ruptures provides information on the following:
a) the resistance of the dough to deformation, or its stiffness. It is expressed by the maximum pressure
parameter, P;
b) the extensibility or the possibility of inflating the dough to form a bubble; It is expressed by the
parameters of extensibility, L, or swelling, G;
c) the elasticity of the dough during biaxial extension. It is expressed by the elasticity index, I ;
e
d) the work required to deform the dough bubble until it ruptures, ot its strength, which is proportional
to the area of the Alveogram (sum of the pressures throughout the deformation process). It is
expressed by the parameter, W.
The P/L ratio is a measurement of the balance between stiffness and extensibility.
Alveographs are commonly used throughout the wheat and flour industry, for the following purposes:
— selecting and assessing different varieties of wheat and marketing batches of wheat;
— blending different batches of wheat or flour to produce a batch with given values for the alveographic
criteria (W, P, and L) complying with the proportional laws of blending.
Alveographs are used both on the upstream side of the industry for marketing, selecting and assessing
the different wheat varieties and on the downstream side throughout the baking industries
(see Bibliography).
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Cereals and cereal products — Common wheat (Triticum
aestivum L.) — Determination of alveograph properties of dough
at constant hydration from commercial or test flours and test
milling methodology
1 Scope
Type text.
This International Standard specifies a method of determining, using an Alveograph, the rheological
properties of different types of dough obtained from common wheat flour (Triticum aestivum L.)
produced by industrial milling or laboratory milling.
It describes the Alveograph test and how to use a laboratory mill to produce flour in two stages:
— stage 1: preparation of the wheat grain for milling to make it easier to separate the bran from the
endosperm;
— stage 2: the milling process, including breaking between three fluted rollers, reduction of particle
size between two smooth rollers and the use of a centrifugal sieving machine to grade the products.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 660, Animal and vegetable fats and oils — Determination of acid value and acidity
ISO 712, Cereals and cereal products — Determination of moisture content — Reference method
NF EN 15948, Cereals — Determination of moisture and protein — Method using Near-Infrared-
Spectroscopy in whole kernels
ISO 7700-1:2008, Food products — Checking the performance of moisture meters in use — Part 1: Moisture
meters for cereals
NF EN ISO 12099, Animal feeding stuffs, cereals and milled cereal products — Guidelines for the application
of near infrared spectrometry
3 Principle
The behaviour of dough obtained from a mixture of flour and salt water is evaluated during deformation.
A dough disk (patty) is subjected to a constant air flow; at first it withstands the pressure. Subsequently,
it inflates into a bubble, according to its extensibility, and ruptures. The change in the dough is measured
and recorded in the form of a curve called an Alveogram.
4 Reagents
Unless otherwise specified, use only reagents of recognized analytical grade, and only distilled or
demineralized water or water of equivalent purity.
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
4.1 Sodium chloride solution, obtained by dissolving (25 ± 0,2) g of sodium chloride (NaCl) in water
and then making the volume up to 1 000 ml. This solution shall not be stored for more than 15 days and
its temperature shall be (20 ± 2) °C when used.
4.2 Refined vegetable oil, low in polyunsaturates, such as peanut oil. It is possible to use olive oil if its
acid value is less than 0,4 (determined according to ISO 660). Store in a dark place in a closed container
and replace regularly (at least every three months).
Alternatively, liquid paraffin (also known as “soft petroleum paraffin”), with an acid value of less than
or equal to 0,05 and the lowest possible viscosity [maximum 60 mPa·s (60 cP) at 20 °C].
4.3 Cold degreasing agent, optimum safety.
5 Apparatus
Usual laboratory apparatus and, in particular, the following.
5.1 Mechanical cleaner, fitted with sieves for wheat cleaning, in accordance with the manufacturer's
instructions.
5.2 Conical or riffle sample divider.
5.3 Analytical balance, accurate to 0,01 g.
5.4 Glass burette, of 50 ml in capacity, graduated in 1 ml divisions.
1
5.5 Rotary blender , for grain conditioning and flour homogenization, including the following
components:
5.5.1 Constant speed stirrer.
5.5.2 Two worm screws integral with the flask, possibly via the stopper (one for wheat preparation,
the other for flour homogenization).
5.5.3 Several wide-necked plastic flasks, 2 l capacity.
5.6 Test mill (laboratory mill), manually or automatically operated (see Annex A).
5.7 Complete alveograph system (see Table 1 for specifications and characteristics of the
accessories) including the following devices:
5.7.1 Kneading machine [see Figure 1 for Alveo NG and Alveo PC models; for model Alveolab,
see Figure 2], with accurate temperature control, for dough sample preparation.
5.7.2 Dedicated software on to record the pressure curve as a function of time, perform the
2
calculations and store the tests or other registration systems such as the Alveolink
1
The Chopin MR 2 l rotary blender is an example of a suitable product available commercially. This information
is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO
of this product.
2
For the details concerning the use of the different registration systems please refer to the manufacturer’s instructions.
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
3
5.7.3 Alveograph for measuring the biaxial deformation of the dough test pieces.]. [for models Alveo
NG and Alveo PC, see Figure 1; for model Alveolab, see Figure 2; Including accurate temperature control
and hygrometry control for the AlveoLab mode., It has two rest chambers (Three for the Alveolab), each
containing five plates on which the dough test pieces can be arranged for resting prior to deformation.
5.8 Burette with stopcock, supplied with the apparatus (only for models NG and PC), 160 ml capacity,
graduated in divisions of 0,1 % of moisture content.
NOTE Throughout this International Standard, “content” is expressed as a “mass fraction” (see ISO 80000-9,
[6]
12 ), i.e. the ratio of the mass of substance in a mixture to the total mass of the mixture.
5.9 Thermohydrograph for recording the test environment conditions (temperature and relative
air humidity) as specified in 8.1 and 9.1. In the case of the Alveolab, the test conditions (temperature and
humidity) around the swelling bubble are automatically checked and controlled by the device.
5.10 Volumetric flask, 1 000 ml capacity, complying with the requirements of ISO 1042, class A.
5.11 Pipette, 25 ml capacity, graduated in divisions of 0,1 ml, complying with the requirements
of ISO 835, class A.
3
The methods specified in this International Standard are based on the use of the NG, PC and Alveolab models of Chopin
alveograph which are examples of suitable products commercially available. This information is given for the convenience of
users of this International Standard and does not constitute an endorsement by ISO of this product.
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Key
A Mixer
B Alveograph
1 Burette for adding water
2 Mixer screen
3 Mixing bowl
4 Mixer control panel
5 Alveograph control panel
6 Test plate of the Alveograph unit
7 Resting chamber
Figure 1 — Mixer and Alveograph part of models Alveo NG and Alveo PC
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Key
1 Mixing bowl
2 Water injection nozzle
3 Aveolab control panel
4 Alveograph test chamber
5 Storage compartment for accessories
6 Dough collector and humidifier
7 Resting chamber
8 Salt water tank
Figure 2 — Mixer and alveograph part of the Alveolab Model
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oSIST prEN ISO 27971:2022
ISO/DIS 27971:2022(E) )
Table 1 — Specifications and characteristics of the accessories required for the test
Quantity Value and tolerance
Rotational frequency of the kneading blade (60 ± 2) Hz
Height of sheeting guides (12,0 ± 0,1) mm
Large diameter of the sheeting roller (40,0 ± 0,1) mm
Small diameter of the sheeting roller (33,3 ± 0,1) mm
Inside diameter of the dough cutter (46,0 ± 0,5) mm
Diameter of the aperture created when the moving plate opens (which determines
(55,0 ± 0,1) mm
the effective diameter of the test piece)
Theoretical distance between the fixed and moving plates after clamping (equal to
(2,67 ± 0,01) mm
the thickness of the test piece before inflation)
Volume of air automatically injected to detach the test piece prior to inflating the
(18 ± 2) ml
bubble
a
Air flow ensuring inflation (96 ± 2) l/h
a
On models Alveo Ng and Alveo PC, to adjust the flow rate of the air generator used to inflate the bubble, fit the nozzle
(Figure 4) to
...

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