BS EN ISO 8420-2002 Animal and vegetable fats and oils Determination of content of polar compounds《动植物脂肪和油 极性化合物含量的测定》.pdf

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1、BRITISH STANDARD BS EN ISO 8420:2002 Incorporating Corrigendum No. 1 Animal and vegetable fats and oils Determination of content of polar compounds The European Standard EN ISO 8420:2002 has the status of a British Standard ICS 67.200.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYR

2、IGHT LAWBS EN ISO 8420:2002 This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 10 May 2002 BSI 31 May 2002 ISBN 0 580 39117 5 N

3、ational foreword This British Standard is the official English language version of EN ISO 8420:2002. It is identical with ISO 8420:2002. It supersedes BS EN ISO 8420:1995 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/11, Animal and vegetable fats

4、 and oils, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards

5、Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for th

6、eir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK inter

7、ests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii and iii, a blank page, pages 1 to 8, the

8、Annex ZA page, and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments 13948 Corrigendum No. 1 31 May 2002 Correction to EN ISO foreword and incorporation of Annex ZAEUROPEANSTANDARD N

9、ORMEEUROPENNE EUROPISCHENORM ENISO8420 April2002 ICS67.200.10 SupersedesENISO8420:1995 Englishversion AnimalandvegetablefatsandoilsDeterminationofcontentof polarcompounds(ISO8420:2002) CorpsgrasdoriginesanimaleetvgtaleDtermination delateneurencomposspolaires(ISO8420:2002) TierischeundpflanzlicheFett

10、eundleBestimmungdes GehaltesanpolarenBestandteilen(ISO8420:2002) ThisEuropeanStandardwasapprovedbyCENon11March2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsa

11、ndbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandno

12、tifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMI

13、TTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2002CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO8420:2002ECORRECTED20020515 Foreword Thisdocument(ISO8420:2002)hasbe

14、enpreparedbyTechnicalCommitteeISO/TC34 “Agriculturalfoodproducts“incollaborationwithTechnicalCommitteeCEN/TC307“Oilseeds, vegetableandanimalfatsandoilsandtheirbyproductsMethodsofsamplingandanalysis“, thesecretariatofwhichisheldbyAFNOR. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eit

15、herbypublication ofanidenticaltextorbyendorsement,atthelatestbyOctober2002,andconflictingnational standardsshallbewithdrawnatthelatestbyOctober2002. ThisdocumentsupersedesENISO8420:1995. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsof thefollowingcountriesareboundtoi

16、mplementthisEuropeanStandard:Austria,Belgium, CzechRepublic,Denmark,Finland,France,Germany,Greece,Iceland,Ireland,Italy, Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,Switzerlandandthe UnitedKingdom. Endorsementnotice ThetextoftheInternationalStandardISO8420:2002hasbeenapprovedbyCENasa E

17、uropeanStandardwithoutanymodifications. NOTENormativereferencestoInternationalStandardsarelistedinannexZA(normative). ENISO8420:2002 Reference number ISO 8420:2002(E) OSI 2002INTERNATIONAL STANDARD ISO 8420 Second edition 2002-04-01 Animal and vegetable fats and oils Determination of content of pola

18、r compounds Corps gras dorigines animale et vgtale Dtermination de la teneur en composs polaires 2egaP ENISO8420:2002ii ISO 8420:2002(E) iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of prepar

19、ing 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 li

20、aison 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 3. The main task of

21、 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

22、 drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 8420 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal a

23、nd vegetable fats and oils. This second edition cancels and replaces the first edition (ISO 8420:1990), which has been technically revised. Annexes A and B of this International Standard are for information only. 2egaP ENISO8420:2002blankINTENRATIONAL TSANDADR IS:0248 O2002(E)1Animal and vegetable f

24、ats and oils Determination of content of polar compounds 1 Scope This International Standard describes a method for the determination of the content of polar compounds in animal and vegetable fats and oils, hereinafter referred to as fats. Polar compounds are formed during the heating of fats and th

25、us the method serves to assess the deterioration of frying fats with use. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisio

26、ns of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative

27、document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 661:1989, Animal and vegetable fats and oils Preparation of test sample 3 Term and definition For the purposes of this International Standard, the following term and definition app

28、lies. 3.1 polar compounds constituents of fats which are determined by column chromatography under the conditions specified in this International Standard NOTE 1 The polar compounds content is expressed as a mass fraction in percent. NOTE 2 Polar compounds include polar substances which occur in unu

29、sed fats, such as monoglycerides, diglycerides and free fatty acids, as well as polar transformation products formed during heating as occurs during the frying of food. Non-polar compounds are mostly unaltered triglycerides. 4 Principle A test portion is separated by column chromatography into non-p

30、olar and polar compounds. The non-polar compounds are eluted then weighed. The polar compounds are determined by difference. 5 Reagents and materials Use only reagents of recognized analytical grade, and distilled or demineralized water or water of equivalent purity. 2egaP 2002:0248OSINE2002:0248OSI

31、NE2 ENISO8420:20021IS:0248 O2002(E) 2 5.1 Silica gel, of particle size 0,063 mm to 0,200 mm (70 mesh to 230 mesh), such as Merck No. 7734 1) , adjusted to a water content of 5 % (mass fraction) as follows. Place approximately 180 g of silica gel in the porcelain dish. Dry in an oven at (160 5) C for

32、 at least 4 h with occasional stirring then cool in a desiccator to room temperature. Adjust the water content of the silica gel to 5 % (mass fraction) by placing 152 g of silica gel and 8 g of water in a 500 ml flask. Stopper the flask and shake on a shaking machine for 60 min. Store the silica gel

33、 in a tightly closed container. Remaining parts of the conditioned silica gel have to be used within 24 h, as they cannot be reactivated and reconditioned. 5.2 Elution solvent, prepared by mixing 87 volumes of chromatographic quality light petroleum (boiling range 40 C to 60 C) and 13 volumes of sta

34、bilized diethyl ether (see warning in 9.4.6). 5.3 Sand, acid washed and calcined. 5.4 Cotton wool, surgical quality, non-absorbent. 5.5 Nitrogen, 99,0 % to 99,8 % purity. 6 Apparatus Usual laboratory apparatus and, in particular, the following. 6.1 Round- or flat-bottom glass flasks, with a ground-g

35、lass neck, of 250 ml capacity. 6.2 Chromatographic column, made of glass, of 21 mm internal diameter and 450 mm in length, equipped with a stopcock (preferably made of polytetrafluoroethylene) and having an internal ground-glass joint at the top. 6.3 Dropping funnel, of 250 ml capacity, with a groun

36、d-glass joint to fit the top of the column (6.2). 6.4 Glass rod, about 600 mm in length. 6.5 Rotary evaporator, or other apparatus for removing solvent under vacuum. 6.6 Shaking machine. 7 Sampling It is important that the laboratory receive a sample which is truly representative and has not been da

37、maged or changed during transportation or storage. Sampling is not part of this method specified in this International Standard. A recommended sampling method is given in ISO 5555. 1) Merck No. 7734 is the tradename of a product supplied by Merck. This information is given for the convenience of use

38、rs of this International Standard and does not constitute an endorsement by ISO of this product. Equivalent products may be used if they can be shown to lead to the same results. Pa2eg 0202:0248OSINEEN2002:0248OSI3 ENISO8420:20022ISO 8420:2002(E) 38 Preparation of test sample Prepare the test sample

39、 in accordance with ISO 661. Semisolid and solid samples are heated to a temperature somewhat above their melting points and carefully mixed. Overheating should be avoided. Visible contaminations are removed by filtration after mixing. If water is present a hydrophobic filter shall be used. 9 Proced

40、ure 9.1 Preparation of the column Using the glass rod (6.4), place a wad of the cotton wool (5.4) in the lower part of the column (6.2) and press it down. Pour about 30 ml of the elution solvent (5.2) into the column and remove air by pressing the cotton wool down with the rod. In a beaker, prepare

41、a slurry of 25 g of the silica gel (5.1) in about 80 ml of the elution solvent and pour this slurry into the column using a funnel. Complete the transfer of the silica gel into the column by rinsing the beaker with the elution solvent. Open the stopcock and run off the elution solvent until the leve

42、l of the elution solvent is about 100 mm above the silica gel. Level the silica gel by tapping the column. Add about 4 g of the sand (5.3) through the funnel. Run off the supernatant elution solvent to within 10 mm of the sand layer. Discard the elution solvent used in the preparation of the column.

43、 9.2 Assessment of column efficiency If desired, assess the column efficiency in accordance with annex A. 9.3 Test portion Weigh (2,5 0,1) g of the test sample (clause 8), to the nearest 0,001 g, into a 50 ml volumetric flask. 9.4 Determination 9.4.1 Dissolve the test portion (9.3) in about 20 ml of

44、 the elution solvent (5.2) by slight warming. Allow to cool to room temperature and dilute to 50 ml with elution solvent. 9.4.2 Using a pipette, transfer 20 ml of the test solution (9.4.1) to the prepared column (9.1). Avoid disturbing the surface of the sand. 9.4.3 Weigh, to the nearest 0,001 g, a

45、250 ml flask, previously dried at (103 2) C and cooled in the desiccator, and place it under the outlet of the column. 9.4.4 Open the stopcock and run off the solvent down to the level of the top of the sand layer, collecting the eluate (which contains non-polar compounds) in the 250 ml flask. 9.4.5

46、 Continue the elution of non-polar compounds by adding 150 ml of the elution solvent (5.2) via a dropping funnel (6.3). Adjust the flowrate so that the 150 ml pass through the column in 60 min to 70 min. After completion of the elution, wash any material adhering to the outlet of the column into the

47、 flask with the elution solvent, using a pipette or dropper. Page3 2002:0248OSNIE2egaP 842OSINE0:2002ENI2002:0248OS4 ENISO8420:20023ISO 8420:2002(E) 4 If the polar compounds are required, for example for checking the efficiency of the column, they may be eluted using 150 ml of diethyl ether followin

48、g the procedure described in 9.4.5 and 9.4.6. Discard the silica gel after completing the elution(s). 9.4.6 Remove the solvent from the flask under low vacuum with the aid of a rotary evaporator (6.5) and a water bath controlled at a temperature no higher than 60 C. Avoid losses due to foaming. Blow off residues of the solvent with nitrogen. WARNING Explosive peroxides may develop in diethyl ether. It is important