Rice - Determination of amylose content - Part 2: Spectrophotometric routine method without defatting procedure and with calibration from rice standards (ISO 6647-2:2020)

This document specifies two simplified routine methods for the determination of the amylose mass fraction of milled rice, non-parboiled. The main difference between the two methods is the dispersion procedure: method A specifies hot dispersion, and method B specifies cold dispersion.
Both methods are applicable to rice with an amylose mass fraction higher than 5 %.
NOTE    These methods describe simplified procedures for the preparation of samples, which are frequently used in routine laboratories. The methods use the same reagents as the reference method (see ISO 6647-1), but omit the defatting step. Rice samples where the amylose mass fraction has been determined by the reference method are used as standards.

Reis - Bestimmung des Amylosegehalts - Teil 2: Spektrophotometrische Routineverfahren ohne Entfettungsverfahren und mit Kalibrierung nach Reisstandards (ISO 6647 2:2020)

Dieses Dokument legt zwei vereinfachte Routineverfahren zur Bestimmung des Amylose-Massenanteils von gemahlenem nicht-angekochten Reis fest. Der Hauptunterschied zwischen den beiden Verfahren besteht in der Vorgehensweise bei der Dispergierung: Verfahren A legt die Heiß-Dispergierung fest und Verfahren B legt die die Kalt-Dispergierung fest.
Beide Verfahren sind anwendbar auf Reis mit einem Amylose-Massenanteil von mehr als 5 %.
ANMERKUNG Diese Verfahren beschreiben vereinfachte Vorgehensweisen für die Herstellung von Proben, die in üblichen Laboratorien häufig genutzt werden. Die Verfahren nutzen als Referenzverfahren (siehe ISO 6647-1) dieselben Reagenzien, lassen jedoch den Schritt der Entfettung aus. Als Standards werden Reisproben genutzt, bei denen Amylose-Massenanteil mit dem Referenzverfahren bestimmt wurde.

Riz - Détermination de la teneur en amylose - Partie 2: Méthode spectrophotométrique de routine sans mode opératoire de dégraissage et avec étalonnage à l'aide d'étalons de riz (ISO 6647-2:2020)

Le présent document spécifie deux méthodes de routine simplifiées pour la détermination de la fraction massique d'amylose du riz usiné, non étuvé. La principale différence entre les deux méthodes est le mode opératoire de dispersion: la méthode A spécifie une dispersion à chaud et la méthode B spécifie une dispersion à froid.
Les deux méthodes sont applicables au riz avec une fraction massique d'amylose supérieure à 5 %.
NOTE    Ces méthodes décrivent des modes opératoires simplifiés pour la préparation d'échantillons, qui sont fréquemment utilisés en routine par les laboratoires. Les méthodes utilisent les mêmes réactifs que la méthode de référence (voir l'ISO 6647-1), mais omettent l'étape de dégraissage. Les échantillons de riz pour lesquels la fraction massique d'amylose a été déterminée par la méthode de référence sont utilisés comme étalons.

Riž - Določevanje amiloze - 2. del: Spektrofotometrijska rutinska metoda brez postopka razmaščevanja in s kalibracijo v skladu s standardi za riž (ISO 6647-2:2020)

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Status
Published
Publication Date
11-Aug-2020
Withdrawal Date
27-Feb-2021
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
12-Aug-2020
Completion Date
12-Aug-2020

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SLOVENSKI STANDARD
SIST EN ISO 6647-2:2020
01-oktober-2020
Nadomešča:
SIST EN ISO 6647-2:2015
Riž - Določevanje amiloze - 2. del: Spektrofotometrijska rutinska metoda brez
postopka razmaščevanja in s kalibracijo v skladu s standardi za riž (ISO 6647-
2:2020)
Rice - Determination of amylose content - Part 2: Spectrophotometric routine method
without defatting procedure and with calibration from rice standards (ISO 6647-2:2020)
Reis - Bestimmung des Amylosegehalts - Teil 2: Routinemethode:
Spektrophotometrische Routinemethode ohne Entfettungsverfahren und mit Kalibrierung
nach Reisstandards (ISO 6647-2:2020)
Riz - Détermination de la teneur en amylose - Partie 2: Méthode spectrophotométrique
de routine sans mode opératoire de dégraissage et avec étalonnage à l'aide d'étalons de
riz (ISO 6647-2:2020)
Ta slovenski standard je istoveten z: EN ISO 6647-2:2020
ICS:
67.060 Žita, stročnice in proizvodi iz Cereals, pulses and derived
njih products
SIST EN ISO 6647-2:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 6647-2:2020

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SIST EN ISO 6647-2:2020


EN ISO 6647-2
EUROPEAN STANDARD

NORME EUROPÉENNE

August 2020
EUROPÄISCHE NORM
ICS 67.060 Supersedes EN ISO 6647-2:2015
English Version

Rice - Determination of amylose content - Part 2:
Spectrophotometric routine method without defatting
procedure and with calibration from rice standards (ISO
6647-2:2020)
Riz - Détermination de la teneur en amylose - Partie 2: Reis - Bestimmung des Amylosegehalts - Teil 2:
Méthode spectrophotométrique de routine sans mode Routinemethode: Spektrophotometrische
opératoire de dégraissage et avec étalonnage à l'aide Routinemethode ohne Entfettungsverfahren und mit
d'étalons de riz (ISO 6647-2:2020) Kalibrierung nach Reisstandards (ISO 6647-2:2020)
This European Standard was approved by CEN on 18 July 2020.

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, Turkey 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6647-2:2020 E
worldwide for CEN national Members.

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SIST EN ISO 6647-2:2020
EN ISO 6647-2:2020 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST EN ISO 6647-2:2020
EN ISO 6647-2:2020 (E)
European foreword
This document (EN ISO 6647-2:2020) 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 February 2021, and conflicting national standards
shall be withdrawn at the latest by February 2021.
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 6647-2:2015.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 6647-2:2020 has been approved by CEN as EN ISO 6647-2:2020 without any
modification.

3

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SIST EN ISO 6647-2:2020

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SIST EN ISO 6647-2:2020
INTERNATIONAL ISO
STANDARD 6647-2
Third edition
2020-07
Rice — Determination of amylose
content —
Part 2:
Spectrophotometric routine method
without defatting procedure and with
calibration from rice standards
Riz — Détermination de la teneur en amylose —
Partie 2: Méthode spectrophotométrique de routine sans mode
opératoire de dégraissage et avec étalonnage à l'aide d'étalons de riz
Reference number
ISO 6647-2:2020(E)
©
ISO 2020

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SIST EN ISO 6647-2:2020
ISO 6647-2:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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 2020 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 6647-2:2020
ISO 6647-2:2020(E)

Contents Page
Foreword .iv
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 Procedure. 3
8.1 Determination of moisture . 3
8.2 Preparation of test sample . 3
8.3 Test portion and preparation of the test solution . 3
8.4 Preparation of the blank solution . 3
8.5 Preparation of the calibration graph . 4
8.5.1 Preparation of the set of calibration solutions . 4
8.5.2 Colour development and spectrophotometric measurements . 4
8.5.3 Plotting the calibration graph . 4
8.6 Determination . 4
9 Expression of results . 4
10 Precision . 5
10.1 Interlaboratory test. 5
10.2 Repeatability . 5
10.3 Reproducibility . 5
11 Test report . 6
Annex A (informative) Results of an interlaboratory test for the routine method .7
Bibliography .11
© ISO 2020 – All rights reserved iii

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SIST EN ISO 6647-2:2020
ISO 6647-2:2020(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 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 6647-2:2015), which has been technically
revised. The main changes compared with the previous edition are as follows.
— The set of calibration solutions in ISO 6647-2:2015 were made by rice samples analysed by size
exclusion chromatography. In this document, the set of calibration solutions are made by rice
samples analysed by spectrophotometer UV-VIS, without delipidization.
A list of all parts in the ISO 6647 series can be found on the ISO website.
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.
iv © ISO 2020 – All rights reserved

---------------------- Page: 10 ----------------------
SIST EN ISO 6647-2:2020
INTERNATIONAL STANDARD ISO 6647-2:2020(E)
Rice — Determination of amylose content —
Part 2:
Spectrophotometric routine method without defatting
procedure and with calibration from rice standards
1 Scope
This document specifies two simplified routine methods for the determination of the amylose mass
fraction of milled rice, non-parboiled. The main difference between the two methods is the dispersion
procedure: method A specifies hot dispersion, and method B specifies cold dispersion.
Both methods are applicable to rice with an amylose mass fraction higher than 5 %.
NOTE These methods describe simplified procedures for the preparation of samples, which are frequently
used in routine laboratories. The methods use the same reagents as the reference method (see ISO 6647-1), but
omit the defatting step. Rice samples where the amylose mass fraction has been determined by the reference
method are used as standards.
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 712, Cereals and cereal products — Determination of moisture content — Reference method
ISO 6647-1:2020, Rice — Determination of Amylose content — Reference method — Part 1:
Spectrophotometric method with a defatting procedure by methanol and with calibration solutions of potato
amylose and waxy rice amylopectin
ISO 7301, Rice — Specification
ISO 8466-1, Water quality — Calibration and evaluation of analytical methods and estimation of
performance characteristics — Part 1: Statistical evaluation of the linear calibration function
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6647-1 and ISO 7301 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
Rice is ground to a very fine flour to break up the endosperm structure in order to aid complete
dispersion and gelatinization. A test portion is dispersed in a sodium hydroxide solution. An aliquot
portion is taken to which is added an iodine solution. The absorbance, at 720 nm, of the colour complex
formed is then determined using a spectrophotometer.
© ISO 2020 – All rights reserved 1

---------------------- Page: 11 ----------------------
SIST EN ISO 6647-2:2020
ISO 6647-2:2020(E)

Measurement wavelengths of 620 nm or 680 nm can also be used.
The amylose mass fraction of the sample is then read from a calibration graph, which is prepared by using
rice samples of known amylose mass fraction, determined using the reference method specified above.
...

SLOVENSKI STANDARD
oSIST prEN ISO 6647-2:2019
01-december-2019
Riž - Določevanje amiloze - 2. del: Rutinska metoda: spektrofotometrijska rutinska
metoda brez postopka razmaščevanja in s kalibracijo v skladu s standardi za riž
(ISO/DIS 6647-2:2019)
Rice - Determination of amylose content - Part 2: Routine method: Spectrophotometric
routine method without defatting procedure and with calibration from rice standards
(ISO/DIS 6647-2:2019)
Reis - Bestimmung des Amylosegehalts - Teil 2: Routinemethode:
Spektrophotometrische Routinemethode ohne Entfettungsverfahren und mit Kalibrierung
nach Reisstandards (ISO/DIS 6647-2:2019)
Riz - Détermination de la teneur en amylose - Partie 2: Méthode de routine : méthode
spectrophotométrique de routine sans mode opératoire de dégraissage et avec
étalonnage à l'aide d'étalons de riz (ISO/DIS 6647-2:2019)
Ta slovenski standard je istoveten z: prEN ISO 6647-2
ICS:
67.060 Žita, stročnice in proizvodi iz Cereals, pulses and derived
njih products
oSIST prEN ISO 6647-2:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 6647-2:2019

---------------------- Page: 2 ----------------------
oSIST prEN ISO 6647-2:2019
DRAFT INTERNATIONAL STANDARD
ISO/DIS 6647-2
ISO/TC 34/SC 4 Secretariat: SAC
Voting begins on: Voting terminates on:
2019-10-21 2020-01-13
Rice — Determination of amylose content —
Part 2:
Routine method: Spectrophotometric routine method
without defatting procedure and with calibration from rice
standards
ICS: 67.060
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
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 6647-2:2019(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 2019

---------------------- Page: 3 ----------------------
oSIST prEN ISO 6647-2:2019
ISO/DIS 6647-2:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST prEN ISO 6647-2:2019
ISO/DIS 6647-2:2019(E)

Contents Page
Foreword .iv
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 Procedure. 3
8.1 Determination of moisture . 3
8.2 Preparation of test sample . 3
8.3 Test portion and preparation of the test solution . 3
8.4 Preparation of the blank solution . 3
8.5 Preparation of the calibration graph . 3
8.5.1 Preparation of the set of calibration solutions . 3
8.5.2 Colour development and spectrophotometric measurements . 4
8.5.3 Plotting the calibration graph. . 4
8.6 Determination . 4
9 Expression of results . 4
10 Precision . 4
10.1 Interlaboratory test. 4
10.2 Repeatability . 5
10.3 Reproducibility . 5
11 Test report . 5
Annex A (informative) Results of an interlaboratory test for the routine method .7
Bibliography .11
© ISO 2019 – All rights reserved iii

---------------------- Page: 5 ----------------------
oSIST prEN ISO 6647-2:2019
ISO/DIS 6647-2:2019(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 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.
This third edition cancels and replaces the second edition (ISO/DIS 6647-2:2015), which has been
technically revised.
A list of all parts in the ISO 6647 series can be found on the ISO website.
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.
iv © ISO 2019 – All rights reserved

---------------------- Page: 6 ----------------------
oSIST prEN ISO 6647-2:2019
DRAFT INTERNATIONAL STANDARD ISO/DIS 6647-2:2019(E)
Rice — Determination of amylose content —
Part 2:
Routine method: Spectrophotometric routine method
without defatting procedure and with calibration from rice
standards
1 Scope
This Annex specifies two simplified routine methods for the determination of the amylose mass
fraction of milled rice, non-parboiled. The main difference between the two methods is the dispersion
procedure: method A specifies hot, and method B cold, dispersion.
Both methods are applicable to rice with an amylose mass fraction higher than 5 %.
Note These methods describe simplified procedures for the preparation of samples, which are frequently
used in routine laboratories. The methods use the same reagents as the reference method (see ISO 6647-1), but
omit the defatting step. Rice samples of which the amylose mass fraction has been determined by the reference
method are used as standards.
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 — Reference method
ISO 6647-1, Rice — Determination of Amylose content — Reference method - Part 1: Spectrophotometric
method with a defatting procedure by methanol and with calibration solutions of potato amylose and waxy
rice amylopectin
ISO 7301, Rice — Specification
ISO 8466-1, Water quality — Calibration and evaluation of analytical methods and estimation of
performance characteristics — Part 1: Statistical evaluation of the linear calibration function
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6647-1 and ISO 7301 apply.
4 Principle
Rice is ground to a very fine flour to break up the endosperm structure in order to aid complete
dispersion and gelatinization. A test portion is dispersed in a sodium hydroxide solution, to an aliquot
portion of which is added an iodine solution. The absorbance, at 720 nm, of the colour complex formed
is then determined using a spectrophotometer.
Measurement wavelengths of 620 nm or 680 nm can also be used.
The amylose mass fraction of the sample is then read from a calibration graph, which is prepared by using
rice samples of known amylose mass fraction, determined using the reference method specified above.
© ISO 2019 – All rights reserved 1

---------------------- Page: 7 ----------------------
oSIST prEN ISO 6647-2:2019
ISO/DIS 6647-2:2019(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 Ethanol, a volume fraction of 95 %.
5.2 Sodium hydroxide
1 mol/l solution, for method A.
2 mol/l solution, for method B.
5.3 Sodium hydroxide
0,09 mol/l solution, for method A.
0,18 mol/l solution, for method B.
5.4 Acetic acid, 1 mol/l solution.
5.5 Iodine solution
Weigh (6.8), to the nearest 5 mg, 2,000 g of potassium iodide in a weighing bottle fitted with a stopper.
Add sufficient water to form a saturated solution. Add 0,200 g of iodine, weighed to the nearest 1 mg.
When all the iodine has dissolved, transfer the solution quantitatively to a 100 ml volumetric flask (6.4),
make up to volume with water and mix.
Prepare a fresh solution on each day of use and protect it from light.
6 Apparatus
The usual laboratory apparatus and, in particular, the following.
6.1 Grinder, capable of reducing uncooked milled rice to flour which will pass through a 150 µm to
180 µm (100 mesh to 80 mesh) sieve. A cyclone mill with 0,5 mm screen is recommended.
6.2 Sieve, size 150 µm to 180 µm (100 mesh to 80 mesh).
6.3 Spectrophotometer, with matching cells, usually of pathlength 1 cm, capable of measuring
absorbance at 720 nm (or 620 nm or 680 nm).
6.4 Volumetric flasks, 100 ml.
6.5 Boiling water bath, for method A only
6.6 Magnetic stirrer, capable of stirring at 950 r/min to 1 000 r/min, for method B only.
6.7 Conical flasks, 100 ml.
6.8 Analytical balance, capable of weighing to the nearest 0,000 1 g.
6.9 Pipettes, of capacity 1 ml, 2 ml, 5 ml and 10 ml.
2 © ISO 2019 – All rights reserved

---------------------- Page: 8 ----------------------
oSIST prEN ISO 6647-2:2019
ISO/DIS 6647-2:2019(E)

7 Sampling
A representative sample should have been sent to the laboratory. It should not have been damaged or
changed during transport or storage.
Sampling is not part of the method specified in this part of ISO 6647. A recommended sampli
...

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