SIST EN ISO 8292-2:2010

Animal and vegetable fats and oils - Determination of solid fat content by pulsed NMR - Part 2: Indirect method (ISO 8292-2:2008)

This part of ISO 8292 specifies an indirect method for the determination of the solid fat content in animal and vegetable fats and oils (hereafter designated “fats”) using low-resolution pulsed nuclear magnetic resonance (NMR) spectrometry. Two alternative thermal pre-treatments are specified: one for general purpose fats not exhibiting pronounced polymorphism and which stabilize mainly in the  polymorph; and one for fats similar to cocoa butter which exhibit pronounced polymorphism and stabilize in the  polymorph. Additional thermal pre-treatments, which may be more suitable for specific purposes, are given in an informative annex. The indirect method is less easy to carry out and less reproducible than the direct method, but is more accurate and more universally applicable to all fats. NOTE A direct method is specified in ISO 8292-1.

Tierische und pflanzliche Fette und Öle - Bestimmung des Festanteils von Fett durch das Verfahren mit gepulster magnetischer Kernresonanz - Teil 2: Indirektes Verfahren (ISO 8292-2:2008)

Dieser Teil von ISO 8292 legt ein direktes Verfahren zur Bestimmung des Festanteils von tierischen und pflanzlichen Fetten und Ölen (nachfolgend als „Fette“ bezeichnet) mittels gepulster magnetischer Kern-resonanz (en: nuclear magnetic resonance, NMR) mit niedriger Auflösung fest.
Zwei alternative thermische Vorbehandlungen sind festgelegt: eine für Fette für die allgemeine Verwendung, die keine ausgeprägte Polymorphie aufweisen und die sich in der Polymorphie verfestigen; und eine für kakaobutterähnliche Fette, die eine ausgeprägte Polymorphie aufweisen und die sich in der Polymorphie verfestigen. Zusätzliche thermische Vorbehandlungen, die für bestimmte Zwecke geeigneter sein können, sind in einem informativen Anhang angegeben.
Das direkte Verfahren ist einfach durchzuführen und reproduzierbar, aber es ist wegen des ungefähren Berechnungsverfahrens nicht so genau wie das indirekte Verfahren.
ANMERKUNG Ein indirektes Verfahren ist in ISO 8292 2 festgelegt.

Corps gras d'origines animale et végétale - Détermination de la teneur en corps gras solides par RMN pulsée - Partie 2: Méthode indirecte (ISO 8292-2:2008)

L'ISO 8292-2:2008 spécifie une méthode indirecte pour la détermination de la teneur en corps gras solides dans des corps gras d'origine animale et végétale (appelés ci-après «corps gras») en utilisant un spectromètre de résonance magnétique nucléaire (RMN) pulsée à basse résolution.
Deux prétraitements thermiques possibles sont spécifiés: l'un pour les corps gras à usage général ne présentant pas de polymorphisme prononcé et qui se stabilisent principalement sous la forme polymorphe β', et l'autre pour des corps gras similaires au beurre de cacao qui présentent un polymorphisme prononcé et qui se stabilisent sous la forme polymorphe β. Des prétraitements thermiques supplémentaires, qui peuvent être plus adaptés pour des applications spécifiques, sont indiqués dans une annexe informative.
La méthode indirecte est moins facile à conduire et moins reproductible que la méthode directe, mais elle est plus précise et plus universellement applicable à tous les corps gras.

Živalske in rastlinske maščobe in olja - Določevanje trdnih maščob s pulzno jedrsko magnetno resonanco - 2. del: Posredna metoda (ISO 8292-2:2008)

Ta del ISO 8292 določa posredno metodo za določevanje trdnih maščob v živalskih in rastlinskih maščobah in oljih (v nadaljevanju navedeno kot »maščobe«) z nizko resolucijsko pulzno jedrsko magnetsko resonančno (NMR) spektrometrijo. Določeni sta dve alternativni toplotni predobdelavi:  ena za maščobe za splošno uporabo, ki ne izkazujejo poudarjenega polimorfizma in se stabilizirajo predvsem v  polimorfih, in ena za maščobe, ki so podobne kokosovemu maslu in izkazujejo poudarjen polimorfizem ter se stabilizirajo v  polimorfih.  Dodatne toplotne predobdelave, ki so lahko bolj primerne za določene namene, so podane v informativnem dodatku.  Posredna metoda je težje izvesti in je težje ponovljiva kot neposredna metoda, vendar je bolj natančna in bolj splošno uporabna za vse maščobe. OPOMBA: Neposredna metoda je določena v ISO 8292-1..

General Information

• Status: Published
• Publication Date: 18-Jul-2010
• ICS: 67.200.10 - Animal and vegetable fats and oils
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jun-2010
• Due Date: 13-Aug-2010
• Completion Date: 19-Jul-2010
• Ref Project: EN ISO 8292-2:2010 - Animal and vegetable fats and oils - Determination of solid fat content by pulsed NMR - Part 2: Indirect method (ISO 8292-2:2008)

Relations

• Replaces: SIST EN ISO 8292:1998 - Animal and vegetable fats and oils - Determination of solid fat content - Pulsed nuclear magnetic resonance method (ISO 8292:1991)
• Effective Date: 01-Sep-2010
• Replaces: SIST EN ISO 8292:1998 - Animal and vegetable fats and oils - Determination of solid fat content - Pulsed nuclear magnetic resonance method (ISO 8292:1991)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 8292-2:2010
01-september-2010
1DGRPHãþD
SIST EN ISO 8292:1998
äLYDOVNHLQUDVWOLQVNHPDãþREHLQROMD'RORþHYDQMHWUGQLKPDãþREVSXO]QR
MHGUVNRPDJQHWQRUHVRQDQFRGHO3RVUHGQDPHWRGD,62
Animal and vegetable fats and oils - Determination of solid fat content by pulsed NMR -
Part 2: Indirect method (ISO 8292-2:2008)
Tierische und pflanzliche Fette und Öle - Bestimmung des Festanteils von Fett durch das
Verfahren mit gepulster magnetischer Kernresonanz - Teil 2: Indirektes Verfahren (ISO
8292-2:2008)
Corps gras d'origines animale et végétale - Détermination de la teneur en corps gras
solides par RMN pulsée - Partie 2: Méthode indirecte (ISO 8292-2:2008)
Ta slovenski standard je istoveten z: EN ISO 8292-2:2010
ICS:
67.200.10 5DVWOLQVNHLQåLYDOVNH Animal and vegetable fats
PDãþREHLQROMD and oils
SIST EN ISO 8292-2:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8292-2:2010

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SIST EN ISO 8292-2:2010


EUROPEAN STANDARD
EN ISO 8292-2

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2010
ICS 67.200.10 Supersedes EN ISO 8292:1995
English Version
Animal and vegetable fats and oils - Determination of solid fat
content by pulsed NMR - Part 2: Indirect method (ISO 8292-
2:2008)
Corps gras d'origines animale et végétale - Détermination Tierische und pflanzliche Fette und Öle - Bestimmung des
de la teneur en corps gras solides par RMN pulsée - Partie Festanteils von Fett durch das Verfahren mit gepulster
2: Méthode indirecte (ISO 8292-2:2008) magnetischer Kernresonanz - Teil 2: Indirektes Verfahren
(ISO 8292-2:2008)
This European Standard was approved by CEN on 18 March 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.






EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8292-2:2010: E
worldwide for CEN national Members.

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SIST EN ISO 8292-2:2010
EN ISO 8292-2:2010 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 8292-2:2010
EN ISO 8292-2:2010 (E)
Foreword
The text of ISO 8292-2:2008 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 8292-2:2010 by
Technical Committee CEN/TC 307 “Oilseeds, vegetable and animal fats and oils and their by-products -
Methods of sampling and analysis” 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 October 2010, and conflicting national standards shall be withdrawn at
the latest by October 2010.
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.
This document supersedes EN ISO 8292:1995.
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, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 8292-2:2008 has been approved by CEN as a EN ISO 8292-2:2010 without any modification.

3

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SIST EN ISO 8292-2:2010

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SIST EN ISO 8292-2:2010

INTERNATIONAL ISO
STANDARD 8292-2
First edition
2008-04-01

Animal and vegetable fats and oils —
Determination of solid fat content by
pulsed NMR —
Part 2:
Indirect method
Corps gras d'origines animale et végétale — Détermination de la teneur
en corps gras solides par RMN pulsée —
Partie 2: Méthode indirecte




Reference number
ISO 8292-2:2008(E)
©
ISO 2008

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
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©  ISO 2008
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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Published in Switzerland

ii © ISO 2008 – All rights reserved

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
Contents Page
Foreword. iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Symbols and abbreviated terms .2
5 Principle.2
6 Triolein standard sample .2
7 Apparatus.2
8 Sampling.4
9 Procedure.4
9.1 Measurement protocol and test sample.4
9.2 Oven, water baths and temperature-controlled blocks .4
9.3 NMR spectrometer.4
9.4 Filling the measurement tubes.4
9.5 Removing the thermal history.6
9.6 Equilibrating at the initial temperature and measuring the 100 % liquid signal .6
9.7 Crystallization and tempering .6
9.8 Measuring the SFC .6
9.9 Number of determinations .7
9.10 Cleaning the measurement tubes .7
10 Expression of results.7
11 Precision.8
11.1 Interlaboratory test .8
11.2 Repeatability.8
11.3 Reproducibility.8
12 Test report.8
Annex A (informative) Results of interlaboratory tests.9
Annex B (informative) Theory of indirect method.12
Annex C (informative) Additional measurement protocols.14
Bibliography .16

© ISO 2008 – All rights reserved iii

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 8292-2 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal
and vegetable fats and oils.
This part of ISO 8292, together with ISO 8292-1, cancel and replace ISO 8292:1991.
ISO 8292 consists of the following parts, under the general title Animal and vegetable fats and oils —
Determination of solid fat content by pulsed NMR:
⎯ Part 1: Direct method
⎯ Part 2: Indirect method

iv © ISO 2008 – All rights reserved

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SIST EN ISO 8292-2:2010
INTERNATIONAL STANDARD ISO 8292-2:2008(E)

Animal and vegetable fats and oils — Determination of solid fat
content by pulsed NMR —
Part 2:
Indirect method
1 Scope
This part of ISO 8292 specifies an indirect method for the determination of the solid fat content in animal and
vegetable fats and oils (hereafter designated “fats”) using low-resolution pulsed nuclear magnetic resonance
(NMR) spectrometry.
Two alternative thermal pre-treatments are specified: one for general purpose fats not exhibiting pronounced
polymorphism and which stabilize mainly in the β′-polymorph; and one for fats similar to cocoa butter which
exhibit pronounced polymorphism and stabilize in the β-polymorph. Additional thermal pre-treatments, which
may be more suitable for specific purposes, are given in an informative annex.
The indirect method is less easy to carry out and less reproducible than the direct method, but is more
accurate and more universally applicable to all fats.
NOTE A direct method is specified in ISO 8292-1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 661, Animal and vegetable fats and oils — Preparation of test sample
ISO 3960, Animal and vegetable fats and oils — Determination of peroxide value — Iodometric (visual)
endpoint determination
ISO 8292-1, Animal and vegetable fats and oils — Determination of solid fat content by pulsed NMR — Part 1:
Direct method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8292-1 apply.
© ISO 2008 – All rights reserved 1

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
4 Symbols and abbreviated terms
f conversion (extrapolation) factor to correct the NMR signal observed at 11 µs to that at time zero
n number of pulses
p
S magnetization decay signal measured at about 11 µs
1
S magnetization decay signal measured at about 70 µs
2
SFC solid fat content
S magnetization decay signal corresponding to the liquid phase
L
S magnetization decay signal corresponding to the solid phase
S
S magnetization decay signals corresponding to both solid and liquid phases
S+L
t repetition time
rep
w “true” SFC (measured in accordance with this part of ISO 8292)
SFC,i
w SFC at measurement temperature, T
SFC,T
5 Principle
The sample is tempered to a stable state at a specific temperature and then heated to, and stabilized at, the
measurement temperature. Unless otherwise specified, measurement temperatures can be any or all of: 0 °C;
5 °C; 10 °C; 15 °C; 20 °C; 25 °C; 27,5 °C; 30 °C; 32,5 °C; 35 °C; 37,5 °C; 40 °C; 45 °C; 50 °C; 55 °C; 60 °C.
After electromagnetic equilibration in the static magnetic field of the NMR spectrometer and application of a
90º radio frequency pulse, the magnetization decay signal from the protons in the liquid phase only is
measured and the solid fat calculated by reference to a standard sample consisting entirely of liquid fat.
Provided that the liquid fat measurements have been made at the start of the SFC determination, results can
be displayed immediately as in the direct method.
6 Triolein standard sample
The liquid fat standard sample shall contain a minimum 99 % mass fraction of triolein. The peroxide value
determined according to ISO 3960 shall be less than 5. Store triolein stocks at a temperature below 0 °C.
Store reference tubes containing triolein in a refrigerator at 0 °C to 8 °C when not in use, and replace them
every 2 weeks.
7 Apparatus
7.1 Pulsed nuclear magnetic resonance (NMR) spectrometer, low resolution
The NMR spectrometer shall have:
a) a magnet with a sufficiently uniform field to ensure that the half-life of the magnetization of a reference
sample of liquid fat is longer than 1 000 µs;
b) an automatic measuring device which operates as soon as the measurement tubes (7.2) are inserted;
c) an adjustable measurement repetition time;
d) a 10 mm measurement cell/probe for test portion tubes which is temperature-controlled at 40 °C.
For preference, the instrument should be equipped with a computer which automatically takes the required
measurements, performs the required calculations and presents the results directly on the computer screen or
other display.
2 © ISO 2008 – All rights reserved

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
7.2 Measurement tubes
Made of glass with plastic caps, with outer diameter (10 ± 0,25) mm, wall thickness (0,9 ± 0,25) mm, and
length at least 150 mm, or as specified by the NMR spectrometer manufacturer.
7.3 Temperature-maintenance equipment
7.3.1 General
In principle, temperature-controlled blocks have advantages over water baths because the tubes can never
come into contact with water. In practice, as with aluminium blocks in water baths, the tubes may take a
significant time to come to the set temperature. Heat transfer can be improved if the tube wells are purged
with a dry gas. Blocks are also more difficult to control precisely than water baths, although modern electronic
controls may provide the required precision.
7.3.2 Water baths
Baths are required at temperatures of (0 ± 0,1) °C, (60 ± 0,1) °C, and, to within ± 0,1 °C, the measuring and
tempering temperatures required according to the measurement protocol chosen. For the 60 °C,
measurement temperature, and tempering temperature baths, temperature-controlled blocks (7.3.3) may be
substituted. Each water bath shall be equipped with either one aluminium block (7.3.2.1) or one metal rack
(7.3.2.2) to accommodate measurement tubes (7.2) immersible in the water to a depth of 60 mm.
Metal racks are preferred to aluminium blocks, especially when a large number of test samples with high SFC
are being measured or when the rapid or ultra-rapid measurement protocols are being used. When using
aluminium blocks, there may be a significant time lag after the tube is inserted before the fat in the tube
reaches the set temperature of the water bath. The perceived advantage of blocks is that the tubes can
remain dry and do not need to be wiped dry with a paper tissue before insertion into the spectrometer. In
practice, however, it is usually found that due to splashing or condensation, the tubes do become wet so that
drying is always recommended, see Clause 9.
7.3.2.1 Aluminium blocks, with holes of diameter (10,35 ± 0,1) mm, and depth 70 mm. The thickness of
the metal under the holes and the distance between the edge of a peripheral hole and the nearest side face
shall be 10 mm. The distance between the axes of two adjacent holes shall be at least 17 mm (centre to
centre).
7.3.2.2 Metal racks, open-sided, with holes of diameter 11 mm to 15 mm; the distance between the axes
of two adjacent holes shall be at least 20 mm (centre to centre).
7.3.3 Temperature-controlled blocks, with holes
The blocks, with electronic control, shall be capable of being maintained to within ± 0,1 °C. These blocks may
be used instead of water baths (except the 0 °C bath, because of the large amount of cooling required). The
diameter of the holes shall be (10,35 ± 0,1) mm.
Blocks are particularly useful at temperatures of 35 °C or more when no cooling is required (assuming the
ambient room temperature is below 22 °C) and where temperature control is less critical because of the
usually lower absolute solid fat levels.
7.4 Oven, with fan
The oven shall be capable of being maintained at (80 ± 2) °C.
Since the purpose of the 80 °C temperature is to melt the test portion and destroy its previous thermal history,
it shall be at least 20 °C above the melting temperature of the fat. If this is not the case, then the oven
temperature shall be raised accordingly and the fact recorded in the test report (Clause 12). This is rarely
necessary, as the fats concerned contain large amounts of long-chain saturated fatty acids, e.g. fully
hydrogenated liquid vegetable oils.
© ISO 2008 – All rights reserved 3

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
Although a water bath (7.3.2) or temperature-controlled block (7.3.3) may be used for the 80 °C temperature,
it is preferable to use an oven. In a block or bath it is almost inevitable that fat will contact the sides, at a
temperature above that of immersion, when filling the tubes. An oven ensures that all the fat in the tube is
completely melted and there are no seed crystals remaining with an unknown thermal history which could
seed the molten fat when it is eventually moved to the 0 °C crystallization temperature. Thus, an oven is likely
to give more reliable and reproducible results.
7.5 Stop-clock
An analogue clock with a large sweep second hand is preferred, although a digital clock may be used.
8 Sampling
A representative sample shall 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 8292. A recommended sampling method is
given in ISO 5555.
9 Procedure
9.1 Measurement protocol and test sample
Choose the required protocol from Table 1 according to the sample type and other requirements. For some
types or applications of fats, the protocols given in Table 1 will not be appropriate. The measurement
protocols given in Annex C may be more suitable.
Prepare the test sample in accordance with ISO 661.
9.2 Oven, water baths and temperature-controlled blocks
Set this equipment up for the required temperatures as specified in the protocol.
9.3 NMR spectrometer
Set the conditions for the spectrometer according to the measurement protocol chosen in 9.1.
9.4 Filling the measurement tubes
From each test sample, fill two measurement tubes. Additionally, fill two tubes with triolein reference sample
(Clause 6). The indirect method has a lower repeatability than the direct method and two tubes are
recommended to obtain similar repeatability for the two methods.
Fill the tubes to a depth of about 10 mm, or as specified by the instrument manufacturer.
NOTE The use of only 10 mm depth with the indirect method, as recommended by instrument manufacturers, will
also require a different spacer to raise the tube so that all the test portion lies within the receiver coil of the NMR
spectrometer. In practice, provided all the tubes are filled to the same height, it will be found that results are little different if
the tubes are filled in the same way as for the direct method, i.e. to a depth of 30 mm to 50 mm, and used with the same
spacer.
Cap the tubes and place in racks that keep the tubes vertical. If metal racks (7.3.2.2) are used, it is very
convenient and time saving to put the filled tubes directly into the racks. The test portions can then be moved
conveniently to the oven and to the water baths without further transfers and handling.
4 © ISO 2008 – All rights reserved

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
© ISO 2008 – All rights reserved 5
Table 1 — Measurement protocols
Measurement Measurement
Second
Tempering
First time
protocol conditions
time at
Instrumental
at 0 °C
Applicable to
0 °C
conditions
Time Temp. Time
No. Name Type
min h °C min min
a
repetition time ,
Non- Fats and blends (comprising mainly vegetable fats,
t = 2 s;
stabilizing hydrogenated and/or interesterified) crystallizing in the β'-
rep
1I b — — (60 ± 2) Series (30 ± 1)
No. pulses , n = 3
indirect polymorph and as used for margarines, spreads, shortenings p
and other general food applications
repetition time,
β-Stabilizing Cocoa butter, cocoa butter equivalents and similar fats
t = 6 s;
2I indirect containing large amounts of 2-oleo-di-saturated (90 ± 2) (40 ± 0,5) 26 (90 ± 2) Series (60 ± 2)
rep
c
No. pulses , n = 1
triacylglycerols and crystallizing in the β-polymorph p
a
Needs to be 6 s for fats in the β-polymorph.
b 2 2
Pulse data are averaged by the instrument. Ideally, three pulses are used, but some older instruments can be set to only either one or four (1 or 2 ) pulses, in which case use four pulses.
c
Use of three pulses would result in sufficient time in the measurement cell to cause the test portion to partially melt and the SFC to reduce during the measurement.

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SIST EN ISO 8292-2:2010
ISO 8292-2:2008(E)
9.5 Removing the thermal history
When all the required tubes have been filled, transfer them to the oven (7.4). Hold at the oven temperature for
a minimum of 15 min.
9.6 Equilibrating at the initial temperature and measuring the 100 % liquid signal
Transfer all the tubes to the 60 °C water bath (7.3.2) or block (7.3.3). Hold for a minimum of 15 min. The time
may be longer than this, but shall not be shorter as otherwise complete equilibration may not be achieved.
For all test portions and triolein reference sample (Clause 6), record the liquid magnetization decay signal
measured at about 70 µs, S . If any of the test portions are not completely liquid, then the measurement
2
procedure shall be repeated using a temperature above 60 °C, at which the test portion is known to melt
completely.
9.7 Crystallization and tempering
From this stage onwards all the times shall be maintained within the tolerances specified here or in the
measurement protocol.
If required by the chosen measurement protocol, transfer the tubes into the 0 °C bath. Leave in the 0 °C bath
for the time specified as “first time at 0 °C” column in the measurement protocol.
If required by the chosen measurement protocol, transfer the tubes into the tempering bath set to the specified
temperature. Leave in the tempering bath for the specified time.
Starting with the reference triolein, at (1,0 ± 0,5) min intervals, transfer the tubes into the 0 °C bath. Leave in
the 0 °C bath for the time specified as “second time at 0 °C” column in the measurement protocol.
9.8 Measuring the SFC
For the indirect method, measurements are made in series.
At (1,0 ± 0,5) min intervals, in exactly the same sequence as they were placed in the 0 °C bath, transfer the
two tubes containing test portions to the first (lowest) of the measurement temperature baths or blocks.
NOTE Experience shows that it is easily possible to transfer a tube from bath or block to the spectrometer and make
the measurement within 15 s. Therefore two tubes may comfortably be processed within 1 min.
After the time specified in the measurement protocol, continuing in exactly the same sequence, transfer the
tubes to the spectrometer. Wipe each tube briefly with a soft paper tissue to remove all water, before placing it
in the measurement cell. Record the SFC (or if automatic calculation is not possible, the liquid magnetization
decay signal measured at about 70 µs, S ). If the NMR spectrometer is equipped with a computer then,
2
provided that the triolein reference sample tubes are measured first, the SFC values can be displayed
immediately in a similar way to that usual for the direct method.
Transfer the tubes containing each test portion to the second (next lowest) of the measurement temperature
baths or blocks at (1,0 ± 0,5) min intervals.
Repeat the procedures from the second paragraph until all the tubes have been measured.
If necessary, calculate the SFC using Equation (1) (see Clause 10).
IMPORTANT — For reliable and reproducible results, adhere to the times and tolerances specified.
This is easily achieved using a laboratory stop-clock (7.5), preferably an analogue clock with a large
sweep second-hand, moving the tubes as the clock moves round to the appropriate time.
Alternatively, if a digital clock is used, it is convenient to set it to 0:00 or 12:00 at the start.
6 © ISO 2008 – All rights reserved

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