Oilseeds — Determination of oil content by the Randall extraction method

This international standard specifies a method using automated Randall extraction for the determination of the hexane extract (or light petroleum extract), called the “oil content”, of oilseeds used as industrial raw materials. The procedure for sunflower seed is different from those for others seeds as it includes an additional moisture content determination after the seed has been ground to prepare the test sample. If required, the pure seeds and the impurities can be analysed separately. In the case of groundnuts, the pure seeds, the total fines, the non-oleaginous impurities and the oleaginous impurities can be analysed separately.

Graines oléagineuses — Détermination de la teneur en huile par la méthode d’extraction Randall

General Information

Status
Not Published
Current Stage
5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
Start Date
08-Oct-2025
Completion Date
08-Oct-2025
Ref Project
Draft
ISO/DTS 21296 - Oilseeds — Determination of oil content by the Randall extraction method Released:9/24/2025
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ISO/DTS 21296 - Graines oléagineuses — Détermination de la teneur en huile par la méthode d’extraction Randall Released:4. 11. 2025
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Standards Content (Sample)


FINAL DRAFT
Technical
Specification
ISO/TC 34/SC 2
Oilseeds — Determination of oil
Secretariat: AFNOR
content by the Randall extraction
Voting begins on:
method
2025-10-08
Graines oléagineuses — Détermination de la teneur en huile par
Voting terminates on:
la méthode d'extraction Randall
2025-12-31
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
Technical
Specification
ISO/TC 34/SC 2
Oilseeds — Determination
Secretariat: AFNOR
of oil content by the Randall
Voting begins on:
extraction method
Graines oléagineuses — Détermination de la teneur en huile par
Voting terminates on:
la méthode d'extraction Randall
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 SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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 Reference number
ii
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
8.1 Reduction of laboratory sample .3
8.2 Predrying .4
8.3 Test sample .4
8.3.1 Preliminary remarks .4
8.3.2 Palm kernels .4
8.3.3 Copra (and coconut) .4
8.3.4 Large- and medium-sized seeds (illipe nuts, shea nuts, groundnuts, soya, etc.,
but not sunflower seed or cottonseed) .4
8.3.5 Sunflower seed .5
8.3.6 Cottonseed .5
8.3.7 Small seeds (linseed, rapeseed, etc.) .5
9 Procedure . 5
9.1 Test portion .5
9.2 Determination .6
9.2.1 Preparation of extraction cups .6
9.2.2 Preparation of Randall extraction system .6
9.3 Extraction .6
9.3.1 First extraction .6
9.3.2 Second extraction .6
9.3.3 Third extraction . .7
9.4 Oil content of impurities .7
10 Calculation and expression of results . 7
10.1 General .7
10.2 Determination on product as received (except sunflower seed) .7
10.3 Determination of oil content on product as received for sunflower seed .8
10.4 Determination of palm kernels .8
10.5 Determination when large non-oleaginous foreign bodies have been separated before
the analysis .8
10.6 Determination of groundnuts .9
10.7 Oil content expressed in relation to the dry matter .9
10.8 Oil content expressed on the basis of any specified moisture content .9
11 Performance of the method . 9
12 Test report . 9
Bibliography .11

iii
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.
The committee responsible for this document is ISO/TC 34, Food products, Subcommittee SC 2, Oleaginous
seeds and fruits and oilseed meals, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 307, Oilseeds, vegetable and animal fats and oils and their by-products —
Methods of sampling and analysis,in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
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
Introduction
This document is an alternative method for the determination of oil content in oilseeds. In case of dispute or
any conflicts, ISO 659 remains the reference method.

v
FINAL DRAFT Technical Specification ISO/DTS 21296:2025(en)
Oilseeds — Determination of oil content by the Randall
extraction method
1 Scope
This document specifies a method using automated Randall extraction for the determination of the hexane
extract (or light petroleum extract), called the “oil content”, of oilseeds used as industrial raw materials.
The procedure for sunflower seed is different from those for others seeds as it includes an additional
moisture content determination after the seed has been ground to prepare the test sample.
If required, the pure seeds and the impurities can be analysed separately. In the case of groundnuts, the
pure seeds, the total fines, the non-oleaginous impurities and the oleaginous impurities can be analysed
separately.
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 658, Oilseeds — Determination of content of impurities
ISO 664, Oilseeds — Reduction of laboratory sample to test sample
ISO 665, Oilseeds — Determination of moisture and volatile matter content
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
3.1
hexane extract
“oil content”
all the substances extracted under the operating conditions specified in this document, expressed as a
percentage by mass of the product as received, or on the cleaned seed
Note 1 to entry: On request, it may be expressed relative to the dry matter.
4 Principle
Oil is extracted from a test portion, with hexane or light petroleum as a solvent, in an automated Randall
extractor. The test portion is submerged in boiling solvent prior to rinsing in cold solvent, reducing the
time needed for extraction. After extraction, the solvent is evaporated and recovered by condensation. The
resulting oil content is determined gravimetrically after drying (see Figure 1).

Stage 1: The sample is immersed in boiling solvent and the extractable material is liberated from the sample.
Stage 2: The level of the solvent is lowered below the extraction thimble. The excess solvent is collected in
the rear solvent recovery tank.
Stage 3: The material is extracted by the refluxed, condensed solvent and is concentrated in the extraction
beaker.
Stage 4: The bulk of the solvent is distilled over into the rear storage tank for later recovery.
Stage 5: The extraction beakers are lifted from the hotplate automatically. Some of the residual solvent may
be removed via convection heating.
Figure 1 — Principle and steps of Randall extraction
5 Reagents
Use only reagents of recognized analytical grade.
5.1 Technical hexane, n-hexane or light petroleum, essentially composed of hydrocarbons with six
carbon atoms, of which less than 5 % distils below 40 °C and more than 95 % distils between 40 °C and
60 °C or between 50 °C and 70 °C, and which has a bromine value of less than 1. The residue on complete
evaporation shall not exceed 2 mg per 100 ml.
6 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
6.1 Automatic Randall extraction system, equipped with several extraction units, consisting of
a heating plate, an extraction cup or beaker (6.2) and a condenser enabling solvent recovery, fitted with
fluoroelastomer or polytetrafluoroethylene seals compatible with petroleum ether or hexane. The system is
also equipped with a control box allowing us to set the extraction system.
6.2 Extraction cups or extraction beaker, of aluminium or glass, compatible with the solvent extraction
system (6.1) and able to receive at least 80 ml of solvent.
6.3 Extraction thimbles, of cellulose, free from petroleum ether or hexane extractable products. The
most common size used is 33 mm × 80 mm, but depending on extraction unit configuration, another size can
be used. See the manufacturer’s instructions.
6.4 Cotton wool, free from petroleum ether or hexane extractable products.
6.5 Drying oven, capable of being maintained at (103 ± 2) °C.
6.6 Desiccator, containing an efficient desiccant (e.g. silica gel, with orange indicator, or P O ).
2 5
6.7 Chiller, able to cool at (15 ± 2) °C.
In cases where a chiller cannot be used, tap water can be used for the reflux condenser.
NOTE Choosing the power of the chiller depends on the number of extraction systems and the temperature used.
For instance, for only one extraction system, it is required to use power of 900 W at 15° C. See the manufacturer’s
instructions for more details.
6.8 Analytical balance, with an accuracy of ±0,001 g.
6.9 Mechanical mill, easy to clean, appropriate for the nature of the oilseeds and allowing the oi
...


ISO/TC 34/SC 2
Date: 2025-08-12
Secretariat: AFNOR
Date: 2025-09-24
Oilseeds — Determination of oil content by the Randall extraction
method
Graines oléagineuses — Détermination de la teneur en huile par la méthode d’extraction ded'extraction Randall

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
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 3
7 Sampling . 4
8 Preparation of test sample . 4
8.1 Reduction of laboratory sample . 4
8.2 Predrying . 4
8.3 Test sample . 4
9 Procedure . 6
9.1 Test portion . 6
9.2 Determination . 6
9.3 Extraction . 7
9.4 Oil content of impurities . 8
10 Calculation and expression of results . 8
10.1 General . 8
10.2 Determination on product as received (except sunflower seed) . 8
10.3 Determination of oil content on product as received for sunflower seed . 8
10.4 Determination of palm kernels . 9
10.5 Determination when large non-oleaginous foreign bodies have been separated before
the analysis. 9
10.6 Determination of groundnuts . 9
10.7 Oil content expressed in relation to the dry matter . 9
10.8 Oil content expressed on the basis of any specified moisture content . 10
11 Performance of the method . 10
12 Test report . 10
Bibliography . 11

iii
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 documentsdocument 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 drawnISO draws attention to the possibility that some of the elementsimplementation of this
document may beinvolve the subjectuse 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. 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.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation onof 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.htmlthe following URL: .
The committee responsible for this document is ISO/TC 34, Food products, Subcommittee SC 2, Oleaginous
seeds and fruits and oilseed meals, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 307, Oilseeds, vegetable and animal fats and oils and their by-products — Methods
of sampling and analysis,in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
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
Introduction
This technical specificationdocument is an alternative method for the determination of oil content in oilseeds.
In case of dispute or any conflicts, ISO 659 – Oilseeds – Determination of oil content remains the reference
method.
v
Oilseeds — Determination of oil content by the Randall extraction
method
1 Scope
This document specifies a method using automated Randall extraction for the determination of the hexane
extract (or light petroleum extract), called the “oil content”, of oilseeds used as industrial raw materials.
The procedure for sunflower seed is different from those for others seeds as it includes an additional moisture
content determination after the seed has been ground to prepare the test sample.
If required, the pure seeds and the impurities can be analysed separately. In the case of groundnuts, the pure
seeds, the total fines, the non-oleaginous impurities and the oleaginous impurities can be analysed separately.
2 Normative references
The following referenced documents are indispensable forreferred to in the applicationtext 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 658, Oilseeds — Determination of content of impurities
ISO 664, Oilseeds — Reduction of laboratory sample to test sample
ISO 665, Oilseeds — Determination of moisture and volatile matter content
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp3.1
— IEC Electropedia: available at https://www.electropedia.org/
3.1
hexane extract
“oil content”
all the substances extracted under the operating conditions specified in this document, expressed as a
percentage by mass of the product as received, or on the cleaned seed
Note 1 to entry: On request, it may be expressed relative to the dry matter.
4 Principle
Oil is extracted from a test portion, with hexane or light petroleum as a solvent, in an automated Randall
extractor. The test portion is submerged in boiling solvent prior to rinsing in cold solvent, reducing the time
needed for extraction. After extraction, the solvent is evaporated and recovered by condensation. The
resulting oil content is determined gravimetrically after drying (see Figure 1fig.1).
Stage 1 : The sample is immersed in boiling solvent and the extractable material is liberated from the sample.
Stage 2 : The level of the solvent is lowered below the extraction thimble. The excess solvent is collected in the rear
solvent recovery tank.
Stage 3 : he material is extracted by the refluxed, condensed solvent and is concentrated in the extraction beaker.
Stage 4 : The bulk of the solvent is distilled over into the rear storage tank for later recovery.
Stage 5 : The extraction beakers are lifted from the hotplate automatically. Some of the residual solvent may be
removed via convection heating.
principle
Stage 1: The sample is immersed in boiling solvent and the extractable material is liberated from the sample.
Stage 2: The level of the solvent is lowered below the extraction thimble. The excess solvent is collected in the rear solvent recovery
tank.
Stage 3: The material is extracted by the refluxed, condensed solvent and is concentrated in the extraction beaker.
Stage 4: The bulk of the solvent is distilled over into the rear storage tank for later recovery.
Stage 5: The extraction beakers are lifted from the hotplate automatically. Some of the residual solvent may be removed via convection
heating.
Figure 1 — Principle and steps of Randall extraction
5 Reagents
Use only reagents of recognized analytical grade.
5.1 Technical hexane, n-hexane or light petroleum, essentially composed of hydrocarbons with six
carbon atoms, of which less than 5 % distils below 40 °C and more than 95 % distils between 40 °C and 60 °C
or between 50 °C and 70 °C, and which has a bromine value of less than 1. The residue on complete
evaporation shall not exceed 2 mg per 100 ml.
6 Apparatus
UsualThe usual laboratory apparatus and, in particular, the following shall be used.
6.1 Automatic Randall extraction system, equipped with several extraction units, consisting of a heating
plate, an extraction cup or beaker (6.2) and a condenser enabling solvent recovery, fitted with fluoroelastomer
or polytetrafluoroethylene seals compatible with petroleum ether or hexane. The system is also equipped with
a control box allowing us to set the extraction system.
6.2 Extraction cups or extraction beaker, of aluminium or glass, compatible with the solvent extraction
system (6.1), and able to receive at least 80 ml of solvent.
6.3 Extraction thimbles, of cellulose, free from petroleum ether or hexane extractable products. The most
common size used is 33 x mm × 80 mm, but depending on extraction unit configuration, another size
couldcan be useused. See the manufacturer’s instructions.
6.4 CotonCotton wool, free from petroleum ether or hexane extractable products.
6.5 Drying oven, capable of being maintained at (103 ± 2) °C.
6.6 Desiccator, containing an efficient desiccant (e.g. silica gel, with orange indicator, or P O ).
2 5
6.7 Chiller, able to cool at (15 ± 2) °C.
NOTE  Failing to be able to use In cases where a chiller cannot be used, tap water couldcan be used for the
reflux condenser.
NOTE The Choosing the power of the chiller to choose will dependdepends on the number of extraction
systemsystems and the temperature used. For instance, for only one extraction system, a it is required to use power of
900W900 W at 15° C has to be used. See the manufacturer’s instructions to getfor more details.
6.8 Analytical balance, with an accuracy of ±0,001 g.
6.9 Mechanical mill, easy to clean, appropriate for the nature of the oilseeds and allowing the oilseeds to
be ground to a uniform particle size without appreciable heating or change in moisture, volatile-matter or oil
content.
NOTE The following mills have been found to give satisfactory results:
1)
— the Christy & Norris 8" laboratory mill , with perforated-plate or bar-type screens depending on the seed type (e.g.
0,8 mm perforated plate, 3 mm and 6 mm bar screens;, see 8.3.2, 8.3.3 and 8.3.4);
1)
— the Retsch ZM 200 ultra-centrifugal mill , with a 1 mm screen for sunflower seed or with other screens depending
on the seed type.
Other mills maycan be satisfactory, provided they conform to the relevant criteria given above.
6.10 Mechanical microgrinder, capable of producing a fineness of grind of the oilseeds of less than 160 µm,
with the exception of the “shell”, particles of which may reach 400 µm. Coffee grinders and similar cutting-
action mechanical grinders shall not be used as microgrinders.

1)
The Christy & Norris 8" mill and the Retsch ZM 200 mill are examples of suitable products available commercially. This
information is given for the convenience of users of this International Standard document and does not constitute an
endorsement by ISO of these products.
NOTE A ball mill comprising a stainless-steel tube of volume approximately 120 ml and 1 cm, 2 cm and 3 cm
diameter steel balls (weighing approximately 7 g, 30 g and 130 g), depending on the sample being ground, and utilizing
extremely rapid shaking, has been found to be suitable.
6.11 Pumice stone, in small particles, or other anti-bumping granules, previously dried in an oven at
(130 ± 2) °C and cooled in a desiccator.
6.12 Drying oven, capable of being maintained at (130 ± 2) °C
7 Sampling
Sampling is not part of the method specified in this document. A recommended sampling method is given in
ISO 21294 [1]. .
It is important that the laboratory receive a sample which is truly representative and has not been damaged
or changed during transport and storage.
8 Preparation of test sample
8.1 Reduction of laboratory sample
Prepare the test sample in accordance with ISO 664. If large non-oleaginous foreign bodies have been
separated before reduction of the laboratory sample, make allowance for this in the calculation (see 10.5).
Depending on the requirements of the contract or the instructions, take the sample as received or afte
...


PROJET FINAL
Spécification
technique
ISO/TC 34/SC 2
Graines oléagineuses —
Secrétariat: AFNOR
Détermination de la teneur en huile
Début de vote:
par la méthode d’extraction Randall
2025-10-08
Oilseeds — Determination of oil content by the Randall extraction
Vote clos le:
method
2025-12-31
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
PROJETS DE NORMES
TRAITEMENT PARALLÈLE ISO/CEN
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
Numéro de référence
PROJET FINAL
Spécification
technique
ISO/TC 34/SC 2
Graines oléagineuses —
Secrétariat: AFNOR
Détermination de la teneur en huile
Début de vote:
par la méthode d’extraction Randall
2025-10-08
Oilseeds — Determination of oil content by the Randall extraction
Vote clos le:
method
2025-12-31
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
DOCUMENT PROTÉGÉ PAR COPYRIGHT
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
© ISO 2025 INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
PROJETS DE NORMES
TRAITEMENT PARALLÈLE ISO/CEN
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
NORMES POUVANT
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: +41 22 749 01 11
E-mail: copyright@iso.org
Web: www.iso.org
Publié en Suisse Numéro de référence
ii
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 1
4 Principe. 1
5 Réactifs . 2
6 Appareillage . 2
7 Échantillonnage . 3
8 Préparation de l’échantillon pour essai . 4
8.1 Préparation de l’échantillon pour laboratoire .4
8.2 Préséchage .4
8.3 Échantillon pour essai .4
8.3.1 Remarques préliminaires .4
8.3.2 Noix de palmiste .4
8.3.3 Coprah (et noix de coco) . .4
8.3.4 Grosses graines et graines de grosseur moyenne (illipé, karité, arachide, soja,
etc., à l’exception des graines de tournesol et des graines de coton) .5
8.3.5 Graines de tournesol .5
8.3.6 Graines de coton .5
8.3.7 Petites graines (lin, colza, etc.) .5
9 Mode opératoire . 6
9.1 Prise d’essai .6
9.2 Détermination .6
9.2.1 Préparation des béchers d’extraction .6
9.2.2 Préparation du système d’extraction Randall .6
9.3 Extraction .7
9.3.1 Première extraction .7
9.3.2 Deuxième extraction.7
9.3.3 Troisième extraction .7
9.4 Teneur en huile des impuretés .7
10 Calcul et expression des résultats . 7
10.1 Généralités .7
10.2 Détermination sur le produit tel que reçu (sauf pour les graines de tournesol) .8
10.3 Détermination de la teneur en huile du produit tel que reçu pour les graines
de tournesol .8
10.4 Détermination de la teneur des noix de palmiste .8
10.5 Détermination lorsque de gros corps étrangers non oléagineux ont été séparés
avant analyse .9
10.6 Détermination de la teneur des arachides .9
10.7 Teneur en huile exprimée par rapport à la matière sèche .9
10.8 Teneur en huile exprimée sur la base de n’importe quelle teneur en eau spécifiée .10
11 Performances de la méthode . 10
12 Rapport d’essai . 10
Bibliographie .11

iii
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes nationaux
de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est en général
confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude a le droit de faire
partie du comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l’ISO participent également aux travaux. L’ISO collabore étroitement avec
la Commission électrotechnique internationale (IEC) en ce qui concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document
a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L’ISO attire l’attention sur le fait que la mise en application du présent document peut entraîner l’utilisation
d’un ou de plusieurs brevets. L’ISO ne prend pas position quant à la preuve, à la validité et à l’applicabilité
de tout droit de brevet revendiqué à cet égard. À la date de publication du présent document, l’ISO n’avait
pas reçu notification qu’un ou plusieurs brevets pouvaient être nécessaires à sa mise en application.
Toutefois, il y a lieu d’avertir les responsables de la mise en application du présent document que des
informations plus récentes sont susceptibles de figurer dans la base de données de brevets, disponible à
l’adresse www.iso.org/brevets. L’ISO ne saurait être tenue pour responsable de ne pas avoir identifié de tels
droits de brevet et averti de leur existence.
Les appellations commerciales éventuellement mentionnées dans le présent document sont données pour
information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion de
l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles techniques au
commerce (OTC), voir www.iso.org/avant-propos.
Le comité responsable du présent document est l’ISO/TC 34, Produits alimentaires, sous-comité SC 2,
Graines et fruits oléagineux et farines de graines oléagineuses, en collaboration avec le comité technique CEN/
TC 307, Oléagineux, corps gras d’origines végétale et animale et leurs co-produits — Méthodes d’échantillonnage
et d’analyse, du Comité européen de normalisation (CEN), conformément à l’Accord sur la coopération
technique entre l’ISO et le CEN (Accord de Vienne).
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www.iso.org/fr/members.html.

iv
Introduction
Le présent document constitue une méthode alternative pour la détermination de la teneur en huile
des graines oléagineuses. En cas de litige ou de conflit, l’ISO 659 reste la méthode de référence.

v
PROJET FINAL Spécification technique ISO/DTS 21296:2025(fr)
Graines oléagineuses — Détermination de la teneur en huile
par la méthode d’extraction Randall
1 Domaine d’application
Le présent document spécifie une méthode utilisant l’extraction Randall automatisée pour déterminer
l’extrait à l’hexane (ou à l’éther de pétrole), dit «teneur en huile», des graines oléagineuses utilisées comme
matières premières industrielles.
Le mode opératoire appliqué aux graines de tournesol est différent de celui employé pour les autres graines
car il inclut une étape supplémentaire pour la détermination de la teneur en eau après la préparation
de l’échantillon pour essai par broyage des graines.
Si cela est exigé, les graines pures et les impuretés peuvent être analysées séparément. Dans le cas de
l’arachide, les graines pures, les poussières totales et les impuretés non oléagineuses et oléagineuses peuvent
être analysées séparément.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique. Pour
les références non datées, la dernière édition du document de référence s’applique (y compris les éventuels
amendements).
ISO 658, Graines oléagineuses — Détermination de la teneur en impuretés
ISO 664, Graines oléagineuses — Réduction de l'échantillon pour laboratoire en échantillon pour essai
ISO 665, Graines oléagineuses — Détermination de la teneur en eau et en matières volatiles
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en normalisation,
consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
3.1
extrait à l’hexane
«teneur en huile»
totalité des substances extraites dans les conditions opératoires spécifiées dans le présent document,
exprimée en pourcentage en masse du produit tel que reçu, ou à la graine nettoyée
Note 1 à l'article: Sur demande, il peut être exprimé par rapport à la matière sèche.
4 Principe
L’huile est extraite d’une prise d’essai, avec de l’hexane ou de l’éther de pétrole comme solvant, dans un
extracteur Randall automatisé. La prise d’essai est immergée dans du solvant bouillant puis rincée dans

du solvant froid, ce qui réduit le temps nécessaire à l’extraction. Après extraction, le solvant est évaporé
et récupéré par condensation. La teneur en huile résultante est déterminée par gravimétrie après séchage
(voir Figure 1).
Étape 1: L’échantillon est immergé dans du solvant bouillant et la matière extractible est libérée de l’échantillon.
Étape 2: Le niveau du solvant est abaissé sous la cartouche à extraction. L’excès de solvant est recueilli dans
le réservoir de récupération de solvant arrière.
Étape 3: La matière est extraite par le solvant chauffé et condensé, et est concentrée dans le bécher d’extraction.
Étape 4: Le solvant est distillé jusqu’à disparition complète et recueilli dans le réservoir de stockage arrière
en vue d’une récupération ultérieure.
Étape 5: Les béchers d’extraction sont automatiquement relevés pour cesser tout contact avec la plaque chauf-
fante. Une partie du solvant résiduel peut être éliminée par chauffage par convection.
Figure 1 — Principe et étapes de l’extraction Randall
5 Réactifs
Utiliser uniquement des réactifs de qualité analytique reconnue.
5.1 Hexane technique, n-hexane ou éther de pétrole, essentiellement composé d’hydrocarbures à six
atomes de carbone, dont moins de 5 % distillent au-dessous de 40 °C et plus de 95 % distillent entre 40 °C et
60 °C ou entre 50 °C et 70 °C, et avec un indice de brome inférieur à 1. Le résidu après évaporation complète
ne doit pas dépasser 2 mg par 100 ml.
6 Appareillage
L’appareillage courant de laboratoire et, en particulier, les éléments suivants doivent être utilisés.
6.1 Système d’extraction Randall automatique, équipé de plusieurs unités d’extraction, constitué d’une
plaque chauffante, d’un flacon d’extraction ou d’un bécher (6.2) et d’un réfrigérant permettant de récupérer
le solvant, muni de joints en fluoroélastomère ou en polytétrafluoroéthylène compatibles avec l’éther de
pétrole et l’hexane. Le système est également équipé d’un boîtier de commande permettant de régler le
système d’extraction.
6.2 Flacons d’extraction ou bécher d’extraction, en aluminium ou en verre, compatibles avec le système
d’extraction par solvant (6.1) et pouvant recevoir au moins 80 ml de solvant.
6.3 Cartouches d’extraction, en cellulose, exemptes de produits extractibles à l’éther de pétrole ou à
l’hexane. La taille la plus couramment utilisée est 33 mm × 80 mm, mais il est possible d’opter pour une
autre taille en fonction de la configuration de l’unité d’extraction. Consulter les instructions du fabricant.
6.4 Ouate hydrophile, exempte de produits extractibles à l’éther de pétrole ou à l’hexane.

6.5 Étuve, pouvant être maintenue à (103 ± 2) °C.
6.6 Dessiccateur, contenant un agent déshydratant efficace (par exemple du gel de silice avec indicateur
de déshydratation orange, ou du P O ).
2 5
6.7 Refroidisseur, pouvant refroidir à (15 ± 2) °C.
Lorsqu’il n’est pas possible de recourir à un refroidisseur, un réfrigérant à reflux peut être utilisé avec de
l’eau du robinet.
NOTE Le choix de la puissance du refroidisseur dépend du nombre de systèmes d’extraction et de la température
appliquée. Par exemple, pour un seul système d’extraction, il est exigé d’utiliser une puissance de 900 W à 15 °C.
Consulter les instructions du fabricant pour plus de détails.
6.8 Balance analytique, d’une précision de ±0 001 g.
6.9 Broyeur mécanique, facile à nettoyer, adapté à la nature des graines oléagineuses et permettant
de broyer celles-ci jusqu’à obtention d’une granulométrie uniforme, sans échauffement notable ni
modification sensible de la teneur en eau, en matières volatiles et en huile.
NOTE Les broyeurs suivants ont donné des résultats satisfaisants:
1)
— le broyeur de laboratoire Christy & Norris 8” équipé de tamis du type plaque perforée ou crible à barreaux,
en fonction du type de graine (par exemple plaque perforée avec trous de 0,8 mm, ou cribles à barreaux de 3 mm
et 6 mm, voir 8.3.2, 8.3.3 et 8.3.4);
1)
— le broyeur ultra-centrifuge Retsch ZM 200 , équipé d’un tamis à 1 mm pour les graines de tournesol ou d’autres
...

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