BS EN ISO 8292-1-2010 Animal and vegetable fats and oils Determination of solid fat content by pulsed NMR Direct method《动物和植物油脂 用脉冲核磁共振(NMR)测定固体脂肪含量 直接法》.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 8292-1:2010Animal and vegetable fats andoils Determination of solidfat content by pulsed NMRPart 1: Direct method (ISO 8292-1:2008)BS EN ISO 8292-1:2010 BRITISH STANDAR

2、DNational forewordThis British Standard is the UK implementation of EN ISO8292-1:2010. Together with BS EN ISO 8292-2:2010, it supersedes BSEN ISO 8292:1995 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oil seeds, animal and vegetable fats and

3、 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 69261 1ICS 67.2

4、00.10Compliance 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 EUROPIS

5、CHE NORM EN ISO 8292-1 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 1: Direct method (ISO 8292-1:2008) Corps gras dorigines animale et vgtale - Dtermination de la teneur en corps gras

6、solides par RMN pulse - Partie 1: Mthode directe (ISO 8292-1:2008) Tierische und pflanzliche Fette und le - Bestimmung des Festanteils von Fett durch das Verfahren mit gepulster magnetischer Kernresonanz - Teil 1: Direktes Verfahren (ISO 8292-1:2008) This European Standard was approved by CEN on 18

7、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 o

8、btained 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 Man

9、agement 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, Nethe

10、rlands, 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 exploitation

11、in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 8292-1:2010: EBS EN ISO 8292-1:2010EN ISO 8292-1:2010 (E) 3 Foreword The text of ISO 8292-1:2008 has been prepared by Technical Committee ISO/TC 34 “Food products” of the International Organization for Standard

12、ization (ISO) and has been taken over as EN ISO 8292-1:2010 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 natio

13、nal 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 paten

14、t 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

15、 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 U

16、nited Kingdom. Endorsement notice The text of ISO 8292-1:2008 has been approved by CEN as a EN ISO 8292-1:2010 without any modification. BS EN ISO 8292-1:2010ISO 8292-1:2008(E) ISO 2008 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 S

17、ymbols and abbreviated terms 2 5 Principle3 6 Apparatus .3 7 Sampling.5 8 Procedure .5 8.1 Measurement protocol and test sample5 8.2 Oven, water baths and temperature-controlled blocks .7 8.3 Determination of the conversion factor (where necessary)7 8.4 NMR spectrometer.8 8.5 Filling the measurement

18、 tubes.8 8.6 Removing the thermal history8 8.7 Equilibrating at the initial temperature8 8.8 Crystallization and tempering 9 8.9 Measuring the SFC 9 8.10 Number of determinations 10 8.11 Cleaning the measurement tubes 10 9 Expression of results 10 10 Precision.11 10.1 Interlaboratory test 11 10.2 Re

19、peatability.11 10.3 Reproducibility.11 11 Test report 12 Annex A (informative) Results of interlaboratory tests.13 Annex B (informative) Theory of the direct method 23 Annex C (informative) Additional measurement protocols25 Bibliography 27 BS EN ISO 8292-1:2010ISO 8292-1:2008(E) iv ISO 2008 All rig

20、hts 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 subject f

21、or 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

22、 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 a

23、re 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

24、responsible for identifying any or all such patent rights. ISO 8292-1 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 8292-2, cancel and replace ISO 8292:1991. ISO 8292 consists of the foll

25、owing 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 8292-1:2010INTERNATIONAL STANDARD ISO 8292-1:2008(E) ISO 2008 All rights reserved 1Animal and vegetable fats and oils Dete

26、rmination of solid fat content by pulsed NMR Part 1: Direct method 1 Scope This part of ISO 8292 specifies a direct method for the determination of solid fat content in animal and vegetable fats and oils (hereafter designated “fats”) using low-resolution pulsed nuclear magnetic resonance (NMR) spect

27、rometry. 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

28、thermal pre-treatments, which may be more suitable for specific purposes, are given in an informative annex. The direct method is easy to carry out and is reproducible, but is not as accurate as the indirect method due to the approximate method of calculation. NOTE An indirect method is specified in

29、 ISO 8292-2. 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, Anim

30、al and vegetable fats and oils Preparation of test sample ISO 8292-2, Animal and vegetable fats and oils Determination of solid fat content by pulsed NMR Part 2: Indirect method 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 solid fat conten

31、t SFC ratio as a percentage of the number of protons in the solid phase to the number of protons in the solid and liquid phase at a specified temperature NOTE SFC expressed on this basis is taken to be numerically equivalent to the percentage mass fraction of fat in the solid state. No correction is

32、 made for the different densities of protons in the solid and liquid phases, because this would require exact knowledge of the composition of the solid and liquid phases of the fat blends at each temperature. Regardless of any other systematic errors, this means that SFC values obtained by this meth

33、od are about 0,5 % to 1,0 % higher than the true solid fat percentage mass fraction. BS EN ISO 8292-1:2010ISO 8292-1:2008(E) 2 ISO 2008 All rights reserved3.2 liquid fat content percentage mass fraction of fat in the liquid state at a specified temperature NOTE The liquid fat content is equal to 100

34、 wSFC, where wSFCis the solid fat content. 3.3 tempering thermal treatment of the fat, after crystallization and prior to equilibration at the measurement temperature, which consists of holding the fat at a specified temperature for a specified time to transform the fat to a desired polymorph, and/o

35、r to ensure that a desired phase equilibrium has been achieved and/or to ensure that crystallization is complete 3.4 measurement temperature temperature at which the solid fat content is determined 3.5 repetition time interval between successive pulses 3.6 dead time time during which the instrument

36、receiver is unable to record the decay signal NOTE Dead time is usually less than 10 s after the pulse. 3.7 measurement protocol complete description of the solid fat content determination specifying application, instrumental conditions, method, tempering, and whether measurements are in series or i

37、n parallel NOTE Measurement protocols are listed in Table 1 and Annex C. 4 Symbols and abbreviated terms f conversion (extrapolation) factor to correct the NMR signal observed at 11 s to that at time zero npnumber of pulses S1magnetization decay signal measured at about 11 s S2magnetization decay si

38、gnal 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+Lmagnetization decay signals corresponding to both solid plus liquid phases treprepetition time wSFC,i“true” SFC (measured

39、 in accordance with ISO 8292-2) wSFC,TSFC at measurement temperature, T BS EN ISO 8292-1:2010ISO 8292-1:2008(E) ISO 2008 All rights reserved 35 Principle The sample is tempered to a stable state at a specific temperature and then heated to, and stabilized at, the measurement temperature. Unless othe

40、rwise 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 90 radio frequency pulse,

41、the magnetization decay signals from the protons in the solid and liquid phases are recorded at about 11 s and about 70 s (or at times recommended by the spectrometer manufacturer, see 6.1). SFC is then calculated. Measurements may be made in series or in parallel. One tube is filled from each test

42、sample when making measurements in series. After tempering as required and holding at 0 C, the measurement tube is moved to the first measurement temperature, held for the specified time, the SFC measured, and then moved to the second measurement temperature, and so on. Thus, only one tube is requir

43、ed for all test samples, regardless of how many measurement temperatures are used. However, the SFC recorded at a given measurement temperature depends on the preceding measurement temperatures and times. As many measurement tubes are filled from each test sample as there are measurement temperature

44、s when making measurements in parallel. After tempering as required and holding at 0 C, each measurement tube is moved more or less simultaneously to each required measurement temperature and held for the specified time before measuring the SFC. Although more tubes are required for measurement in pa

45、rallel than with that in series, each wSFC,Tdetermination is independent of other determinations. Additionally, the total time for the measurements is significantly shortened. EXAMPLE For a holding time of 90 min at 0 C and holding times of 60 min at measurement temperatures of 10 C, 20 C, 30 C, and

46、 40 C, the series measurement would take 5,5 h, whereas the parallel measurement would take 2,5 h. 6 Apparatus 6.1 Pulsed nuclear magnetic resonance spectrometer, low resolution The NMR spectrometer shall have: a) a magnet with a sufficiently uniform field to ensure that the half-life of the magneti

47、zation of a reference sample of liquid fat is longer than 1 000 s; b) a measurement dead time plus pulse width of less than 10 s; c) an automatic measuring device which operates as soon as the measurement tubes (6.2.1) are inserted; d) an adjustable measurement repetition time; e) a 10 mm measuremen

48、t cell/probe for measurement tubes which is temperature controlled at 40 C. For exact magnetization decay signal times, refer to spectrometer manufacturers instructions; these are normally at about 11 s and about 70 s and should not need to be altered by the user. For preference, the instrument shou

49、ld 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. BS EN ISO 8292-1:2010ISO 8292-1:2008(E) 4 ISO 2008 All rights reserved6.2 Tubes 6.2.1 Measurement tubes, 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. 6.2.2 Calibration tube