EN ISO 7973:2015

SLOVENSKI STANDARD
01-marec-2016
äLWRLQPOHYVNLåLWQLSURL]YRGL'RORþDQMHYLVNR]QRVWLPRNH0HWRGD]
DPLORJUDIRP,62
Cereals and milled cereal products - Determination of the viscosity of flour - Method
using an amylograph (ISO 7973:1992)
Getreide und gemahlene Getreideerzeugnisse - Bestimmung der Viskosität von Mehl -
Amylograph-Verfahren (ISO 7973:1992)
Céréales et produits de mouture des céréales - Détermination de la viscosité de la farine
- Méthode utilisant un amylographe (ISO 7973:1992)
Ta slovenski standard je istoveten z: EN ISO 7973:2015
ICS:
67.060 äLWDVWURþQLFHLQSURL]YRGLL] Cereals, pulses and derived
QMLK products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 7973
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2015
EUROPÄISCHE NORM
ICS 67.060
English Version
Cereals and milled cereal products - Determination of the
viscosity of flour - Method using an amylograph (ISO
7973:1992)
Céréales et produits de mouture des céréales - Getreide und gemahlene Getreideerzeugnisse -
Détermination de la viscosité de la farine - Méthode Bestimmung der Viskosität von Mehl - Amylograph-
utilisant un amylographe (ISO 7973:1992) Verfahren (ISO 7973:1992)
This European Standard was approved by CEN on 30 November 2015.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7973:2015 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
The text of ISO 7973:1992 has been prepared by Technical Committee ISO/TC 34 “Food products” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 7973:2015 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 June 2016, and conflicting national standards shall be
withdrawn at the latest by June 2016.
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,
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, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 7973:1992 has been approved by CEN as EN ISO 7973:2015 without any modification.

INTERNATIONAL
STANDARD
First edi tion
19924 2-o 1
Cereals and milled cereal products -
Determination of the viscosity of flour - Method
using an amylograph
Ckeales et produits de mouture des c&&ales - Dbtermination de la
viscosite de la farine - Methode utilisant un amylographe
Reference number
ISO 7973: 1992(E)
ISO 7973:1992(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. Esch 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, govern-
mental and non-governmental, in liaison with ISO, also take patt in the
work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard ISO 7973 was prepared by Technical Committee
ISO/TC 34, Agricultural food products, Sub-Committee SC 4, Cereals and
pulses.
This International Standard takes into account Standard No. 126 of the
International Association for Cereal Science and Technology (ICC).
Annex A forms an integral part of this International Standard. Annexes
B and C are for information only.
0 ISO 1992
All rights reserved. No patt of this publication may be reproduced or utiiized in any form
or by any means, electronie or mechanical, including photocopying and microfilm, without
Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
ISO 7973:1992(E)
INTERNATIONAL STANDARD
Cereals and milled cereal products - Determination of the
viscosity of flour - Method using an amylograph
ISO 3093:1982, Cereals - Determination of falling
1 Scope
number.
This International Standard specifies a method using
an amylograph for determining the viscosity of a
Suspension of flour in watet-, in which the starch is 3 Definition
gelatinized by heating, in Order io assess the con-
ditions of gelatinization of the flour and so judge
For the purposes of this International Standard, the
whether there is any alpha-amylase activity.
following definition applies.
This method is applicable to wheat and rye flour and
3.1 amylograph viscosity: Maximum viscosity
also to wheat and rye grain.
reached by a Suspension of flour and water which is
gelatinized by heating under the conditions set out
NOTES
in this International Standard.
1 This International Standard has been prepared on the
lt is expressed as an arbitrary unit: amylograph unit
basis of the Brabender-type amylograph.
(AU) n
2 This method applies strictly to an amylograph and not
to a viscograph, since an amylograph possesses the fol-
lowing characteristics:
4 Principle
it is possible to Change the torque-measuring head;
-
Preparation of a Suspension of flour in watet-, fol-
- the heating coils are located around the bowl of the lowed by recording of the viscosity of the suspen-
apparatus and at the bottom;
sion which is heated at a constant rate from 30 ‘C
to the temperature corresponding to the moment at
- there is no cooling rod for lowering the gel tempera-
which viscosity Starts to decrease, having reached
ture.
its maximum (approximately 95 “C).
The increase in viscosity due to gelatinization of the
starch is dependent upon the increase in tempera-
2 Normative references
ture, the mechanical action of stirring and the ac-
tivity of alpha-amylase already present or added to
The following Standards contain provisions which,
the flour.
through reference in this text, constitute provisions
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All stan-
5 Reagent
dards are subject to revision, and Parties to
agreements based on this International Standard
are encouraged to investigate the possibility of ap-
5.1 Distillled water, or water of equivalent purity.
plying the most recent editions of the Standards in-
dicated below. Members of IEC and ISO maintain
registers of currently valid Internaiional Standards.
6 Apparatus
ISO 712:1985, Cereals and cereal products - Deter-
mination of moisture content (Routine reference Usual laboratory equipment and, in particular, the
following.
method).
ISO 7973:1992(E)
6.1 Amylograph, having the following character-
7 Sampling
istics:
It is important that the laboratory receive a Sample
Speed of rotation of
which is truly representative and has not been
the spindle (75 + 1) rev/min
damaged or changed during transport and storage.
Torque exerted per
Sampling is not part of the method specified in this
amylograph unit
International Standard. Recommended sampling
(AU), using a stan-
methods are given in ISO 950 (for grains) and
dard measuring (6,86 & 0,14) x 10m5 N.m/AU
ISO 2170 (for milled products).
cartridge [(0,700 rt: 0,015) gf.cm/AU)]
Rate of temperature
rise (1,50 + 0,03) “C/min 8 Procedure
Linear Speed of the
recorder (0,50 + 0,Ol) cmlmin
8.1 Preparation of test Sample
Position the sensing pins and the pins of the bowl
8.1 .l Flour
so that they penetrate freely into the jig provided by
the manufacturer.
Use the laboratory Sample as provided, after thor-
ough mixing, taking test samples as required.
Adjust the pressure of the pen on the Paper as fol-
lows. Remove the pen, fill it with ink and weigh it.
At the end of the arm which normally holds the pen, 8.1.2 Grain
place a mass 0,5 g to. 1 g less than that of the com-
pletely filled pen. Adjust the Position of the counter-
Remove dust and coarse impurities from the lab-
weight to obtain equilibrium then remove the mass
oratory Sample and then take approximately 300 g
and replace the pen.
of grain.
Grind the Sample carefully in the mill (6.6), avoiding
heating or overloading.
6.2 Analytical baiante, accurate to within 0,l g.
Continue grinding for 30 s to 40 s alter the last of the
Sample has been fed into the mill. Bran particles up
6.3 Wrette, of 450 ml capacity, with an automatic
to 1 % remaining on the Screen may be discarded.
zeroing System.
Thoroughly mix the milled product.
6.4 Shallow beaker, of capacity 600 ml to 1000 ml,
8.2 Preliminary operations
or a conical flask with stopper.
8.2.1 Determination of the moisture content of the
6.5 Spatula, with a rubber or plastic end. test Sample
Determine the moisture content of the test Sample
(8.1) in accordance with ISO 712.
6.6 Milll), complying with the requirements of
ISO 3093 in the case of wheat and rye grains; i.e.
capable of grinding a product of moisture content
8.2.2 Adjustment of the amylograph and no-load
up to 30 % (m/m) and with adjustment to obtain a
test
meal meeting the requirements of table 1.
Manually adjust the starting temperature of the
temperature regulator to 30 OC, with the clutch in the
Table 1 - Particle size requirements
neutral Position. Fill the pen with ink. Place the
Meal passing through the
spindle in the bowl, connect the spindle to the shaft
Mesh opening of sieve
sieve
and lower the amylograph head into Position. Start
%
Pm
the motor and check that the pen moves over the
baseline of the recording Paper. If necessary, adjust
710 100
the Position of the pen on its arm. Stop the motor,
500 95 to 100
disconnect the spindle, lift and turn the head of the
210 to 200 80 or less
apparatus. Remove the spindle.
1) Kamas Slago 200 A and Falling Number type KT 120 mills are examples of suitable commercially available products.
This information is given for the convenience of users of this International Standard and does not constitute an endorse-
ment by ISO of the products named. Equivalent products may be used if they tan be shown to lead to the same results.
ISO 7973:1992(E)
CAUTION - Refer to annex A for the calibration of 8.4.4 lt is important that operations 8.4.1, 8.4.2 and
8.4.3 be completed within 2 min.
the amylograph. Particular care shall be taken when
adjusting the contact thermometer as its Position has
a marked influence on the results. 8.4.5 In the case of grain, the mass of the test por-
tion plus the mass of water should equal
540,O g + 0,5 g (corresponding to 90 g of flour and
450 g ofiater).
8.3 Test Portion
8.3.1 For flour
8.5 Amylograph test
Weigh, to the nearest 0,l g, the equivalent of 80,O g
of flour with a moisture content of 14,0 % (m/m).
This mass, m, in grams, is given in table 2 as a
function of moisture content.
8.51 Place the spindle in the amylograph bowl.
Connect it to the shaft and carefully lower the head
of the apparatus.
8.3.2 For grain
8.52 Start the motor and switch on the heater and
Adjust the mass of the test Portion so that 90,O g of
timer. As soon as the heater cuts out (automat-
milled product corresponds to a moisture content of
ically), mark the next line up on the recording Paper.
14,0 % (m/m). This mass, m, in grams, is also given
At the moment that this line Passes under the pen,
in table 2 as a function of moisture content.
place the clutch in the up Position.
Set the timer to ring at the desired time. For wheat
8.4 Preparation of Suspension
the time taken to obtain the viscosity curve is
40 min to 45 min or less, and for rye it is 30 min t
...