1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 8292-2:2010Animal and vegetable fats andoils Determination of solidfat content by pulsed NMRPart 2: Indirect method (ISO 8292-2:2008)BS EN ISO 8292-2:2010 BRITISH STAND
2、ARDNational forewordThis British Standard is the UK implementation of EN ISO8292-2:2010. Together with BS EN ISO 8292-1:2010, it supersedes BSEN ISO 8292:1995 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oil seeds, animal and vegetable fats a
3、nd oilsand their by products.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 69262 8ICS 67
4、.200.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 October 2010.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROP
5、ISCHE NORM EN ISO 8292-2 April 2010 ICS 67.200.10 Supersedes EN ISO 8292:1995English 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 dorigines animale et vgtale - Dtermination de la teneur en corps g
6、ras solides par RMN pulse - Partie 2: Mthode indirecte (ISO 8292-2:2008) Tierische und pflanzliche Fette und le - Bestimmung des Festanteils von Fett durch das Verfahren mit gepulster magnetischer Kernresonanz - Teil 2: Indirektes Verfahren (ISO 8292-2:2008) This European Standard was approved by CE
7、N 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
8、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
9、 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, Malt
10、a, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of explo
11、itation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 8292-2:2010: EBS EN ISO 8292-2:2010EN ISO 8292-2:2010 (E) 3 Foreword The text of ISO 8292-2:2008 has been prepared by Technical Committee ISO/TC 34 “Food products” of the International Organization for
12、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
13、 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
14、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
15、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 a
16、nd 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. BS EN ISO 8292-2:2010ISO 8292-2:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references 1 3 Terms and definition
17、s .1 4 Symbols and abbreviated terms 2 5 Principle2 6 Triolein standard sample 2 7 Apparatus .2 8 Sampling.4 9 Procedure .4 9.1 Measurement protocol and test sample4 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
18、 thermal history6 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
19、 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 method12 Annex C (informative) Additional measurement protocols14 Bibliography 16 BS EN ISO 8292-2:2010ISO 8292-2:2008(E) iv ISO 2008 All
20、rights reservedForeword 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 subjec
21、t 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)
22、 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 committee
23、s 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 he
24、ld 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 f
25、ollowing 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 BS EN ISO 8292-2:2010INTERNATIONAL STANDARD ISO 8292-2:2008(E) ISO 2008 All rights reserved 1Animal and vegetable fats and oils D
26、etermination 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
27、 (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.
28、 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
29、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
30、. 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: Dir
31、ect method 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 8292-1 apply. BS EN ISO 8292-2:2010ISO 8292-2:2008(E) 2 ISO 2008 All rights reserved4 Symbols and abbreviated terms f conversion (extrapolation) factor to correct the NMR signal observed at 1
32、1 s to that at time zero npnumber of pulses S1magnetization decay signal measured at about 11 s S2magnetization decay signal measured at about 70 s SFC solid fat content SLmagnetization decay signal corresponding to the liquid phase SSmagnetization decay signal corresponding to the solid phase SS+Lm
33、agnetization decay signals corresponding to both solid and liquid phases treprepetition time wSFC,i“true” SFC (measured in accordance with this part of ISO 8292) wSFC,TSFC at measurement temperature, T 5 Principle The sample is tempered to a stable state at a specific temperature and then heated to,
34、 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
35、spectrometer and application of a 90 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
36、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 triol
37、ein 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 s
38、ufficiently uniform field to ensure that the half-life of the magnetization of a reference sample of liquid fat is longer than 1 000 s; 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 measur
39、ement 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
40、 display. BS EN ISO 8292-2:2010ISO 8292-2:2008(E) ISO 2008 All rights reserved 37.2 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-mai
41、ntenance 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 tra
42、nsfer 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 with
43、in 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 bloc
44、k (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 prot
45、ocols 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
46、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
47、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 di
48、stance 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, b
49、ecause 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 t
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