1、BRITISH STANDAR BS EN ISO 6886:2008Animal and vegetable fats and oils Determination of oxidative stability (accelerated oxidation test)ICS 67.200.10nullnull nullnullnullnullnullnullnull nullnullnullnullnullnullnull nullnullnull nullnullnullnullnullnullnullnullnullnull nullnullnullnullnullnull nullnu
2、ll nullnullnullnullnullnullnullnullnull nullnull nullnullnullnullnullnullnullnullnull nullnullnullCopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-National forewordThis British St
3、andard is the UK implementation of EN ISO 6886:2008. It is identical with ISO 6886:2006. It supersedes BS ISO 6886:2006 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee AW/307, Oil seeds, animal and vegetable fats and oils and their by products.A list o
4、f organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal ob
5、ligations.BS EN ISO 6886:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI 2009ISBN 978 0 580 63595 3Amendments/corrigenda issued since publicationDate Comments 30 June 2009 This corrigendum renumbers BS ISO 6886:2006 a
6、s BS EN ISO 6886:2008Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 6886November 2008ICS 67.200.10English VersionAnimal and
7、 vegetable fats and oils - Determination of oxidativestability (accelerated oxidation test) (ISO 6886:2006)Corps gras dorigines animale et vgtale - Dterminationde la stabilit loxydation (essai doxydation acclr)(ISO 6886:2006)Tierische und pflanzliche Fette und le - Bestimmung derOxidationsstabilitt
8、(beschleunigter Oxidationstest) (ISO6886:2006)This European Standard was approved by CEN on 23 October 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alterati
9、on. Up-to-date lists and bibliographical references concerning such nationalstandards 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 translati
10、onunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greec
11、e, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Cen
12、tre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 6886:2008: ECopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or net
13、working permitted without license from IHS-,-,-blankCopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-iiiContents Page1Scope. 12Normative references. 13Terms and definitions. 14Pri
14、nciple. 25Reagents and materials. 26Apparatus 27Sampling 38Preparation of test sample and apparatus. 58.1 Preparation of test sample. 58.2 Preparation of apparatus. 59Procedure 610 Calculations. 710.1 Manual calculation 710.2 Automatic calculation.811 Precision 811.1 Results of interlaboratory test.
15、 811.2 Repeatability 811.3 Reproducibility 812 Test report.8Annex A (informative) Summary of the method and examples of conductivity curves and thedetermination of induction time 9Annex B (informative) Results of an interlaboratory test.11Bibliography. 13BS EN ISO 6886:2008Copyright European Committ
16、ee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword The text of ISO 6886:2006 has been prepared by Technical Committee ISO/TC 34 “Agricultural food products” of the International Organization for Sta
17、ndardization (ISO) and has been taken over as EN ISO 6886:2008 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 na
18、tional standard, either by publication of an identical text or by endorsement, at the latest by May 2009, and conflicting national standards shall be withdrawn at the latest by May 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rig
19、hts. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. 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, Cyprus, C
20、zech 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 6886:20
21、06 has been approved by CEN as a EN ISO 6886:2008 without any modification. ivBS EN ISO 6886:2008Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1Animal and vegetable fats and oi
22、ls Determination ofoxidative stability (acceleratedoxidation test) 1 Scope This International Standard specifies a method for the determination of the oxidative stability of fats and oils under extreme conditions that induce rapid oxidation: high temperature and high air flow. It does not allow dete
23、rmination of the stabilityof fats and oils at ambient temperatures, but it does allowa comparison of the efficacy of antioxidants added to fats and oils. The method is applicable to both virgin and refined animal and vegetable fats and oils. NOTE The presence of volatile fatty acids and volatile aci
24、dic oxidation products prevents accurate measurement. 2 NormativereferencesThe following referenced document is indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latestedition of the referenced document (including an
25、y amendments)applies.ISO 661:2003, Animal and vegetable fats and oils Preparation of test sample3 Terms and definitions For the purposes of this document, the following terms and definitions apply.3.1 induction period time between the start of the measurement and the time when the formation of oxida
26、tion products rapidly begins to increase 3.2 oxidative stabilityinduction period, expressed in hours, determined according to the procedure specified in this InternationalStandard NOTE A temperature of 100 C to 120 C is usually applied for the determination of oxidative stability. Depending onthe ox
27、idative stability of the sample under test, or when an extrapolation of regression is required, the determination maybe carried out at other temperatures. The optimal induction period is between 6 h to 24 h. A temperature increase ordecrease of 10 C decreases or increases the induction period by a f
28、actor of approximately 2. 3.3 conductivityabilityof a material to conduct electric current BS EN ISO 6886:2008Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 4 Principle A stre
29、am of purified airis passed through the sample, which has been brought to a specified temperature. The gases released during the oxidation process , together with the air, are passed into a flask containing waterthat has been demineralized or distilled and contains an electrode formeasuring the cond
30、uctivity. The electrode is connected to a measuring and recording device. The end of the induction period is indicated whenthe conductivity begins to increase rapidly . This accelerated increase is caused by the accumulation of volatile fatty acids produced during oxidation. 5 Reagentsand materials
31、Use only reagents of recognized analytical grade, and distilled or demineralized water.5.1 Molecular sieve , beads of approx. 1 mm diameter, pore size 0,3 nm, with moisture indicator.The molecular sieve should be dried in an oven set at 150 C and then cooled down to room temperature in a desiccator.
32、5.2 Acetone .5.3 Alkaline cleaning solution, for laboratoryglassware.5.4 Glycerol .5.5 Thermostable oil.6 Apparatus Usual laboratory equipment and, in particular, the following. 6.1Appliance for the determination of oxidative stabilitySee Figures 1 and 2 for diagrammatic representations.NOTE An appl
33、iance for determining oxidative stability can be obtained commercially under the trade name Rancimat,from Methrom-Herisau AG, Switzerland, or the OSI equipment from Omnion Inc., USA1).6.1.1 Air filter, comprising a tube fitted with filter paper at each end and filled with molecular sieve (5.1),conne
34、cted to the suction end of a pump. 6.1.2 Gas diaphragm pump , with an adjustable flow rate of 10 l/h, in combination with an apparatus tocontrol the flow rate, manuallyor automatically, with a maximum deviation of 1,0 l/h from the set value. NOTE For the OSI instrument, a pressure of 5,5 psi is equi
35、valent to a flow of approximately 10 l/h.6.1.3 Aeration vessels of borosilicate glass (usually eight), connected to a sealing cap. The sealing cap shall be fitted with a gas inlet and outlet tube. The cylindrical part of the vessel shall preferably be narrower by a few centimetres belowthe top in or
36、der to break up any emerging foam. An artificial foam blocker (e.g. glass ring) may also be used for this purpose. 1) Rancimat ( ) and OSI (Omnion) ( http:/ are examples of suitableequipment available commercially. This information is given for the convenience of users of this International Standard
37、and does not constitute an endorsement by ISO of this equipment.BS EN ISO 6886:2008Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-36.1.4 Closed measurement cells (usually eight)
38、,of approx. 150 m l capacity, with a gas inlet tube extending to the bottom inside of the vessel. The cell shall be provided at the top with ventilation holes.6.1.5 Electrodes (usually eight), for measuring conductivitywith a measuring range of 0 S/cm to300 S/cm, aligned with the dimensions of the m
39、easurement cell (6.1.4).6.1.6 Measuring and recording apparatus, comprising an amplifier and a recorder for registering themeasuring signal of each of the electrodes (6.1.5).NOTE A computer-controlled central processing unit is used with Rancimat and OSI (Omnion). 6.1.7Certified and calibrated conta
40、ct thermometer , graduated in 0,1 C, or Pt 100 element (platinumresistance thermometer) to measure the block temperature, with attachments for a control relay connectio n and an adjustable heating element; temperature range 0 C to 150 C.6.1.8 Heatingblock, made of cast aluminium, adjustable to a tem
41、perature of up to 150 C 0,1 C. The block shall be provided with holes (usuallyeight) for the aeration vessels (6.1.3), and an aperture for thecontact thermometer (6.1.7). Alternatively, a heating bath may be used, filled with oil, suitable for temperatures up to 150 C and adjustable to the nearest 0
42、,1 C. 6.2 Certified and calibrated thermometer or Pt100 element, with a temperature range up to 150 C,graduated in 0,1 C. 6.3 Measuringpipettes , of capacity 50 ml and 5 ml. 6.4 Oven , capable of being maintained at a temperature of up to 150 C 3 C. 6.5 Connecting hoses, flexible and made of inert m
43、aterial polytetrafluoroethylene (Teflon) or silicone. 7 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged orchanged during transport or storage. Sampling is not part of the method specified in this International Standard. A recommended sampling
44、 methodis given in ISO5555 1 . Store the sample in the dark at about 4 C. BS EN ISO 6886:2008Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 Key1 air filter (6.1.1) 2 gas diaph
45、ragm pump with flow rate control (6.1.2) 3 aeration vessel (6.1.3) 4 measurement cell (6.1.4) 5 electrode (6.1.5)6 measuring and recording apparatus (6.1.6)7 thyristor and contact thermometer (6.1.7)8 heating block (6.1.8)Figure 1 Diagrammatic representation of the apparatus BS EN ISO 6886:2008Copyr
46、ight European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-5Key1 air 5 aeration vessel2 measurement cell 6 sample 3 electrode 7 heating block 4 measuring solution Figure 2 Diagrammatic represent
47、ation of heating block, reaction vessel and measurement cell 8 Preparation of test sample and apparatus 8.1Preparation of test sample Prepare the test sample in accordance with ISO 661. Remove the required quantity from the centre of the carefullyhomogenized sample using a pipette. Heat semisolid an
48、d solid samples to a temperature somewhat above their melting points and mix carefully.Overheating should be avoided. The pipette shall be at the same temperature as the sample. 8.2Preparation of apparatus 8.2.1 Cleaningprocedure Wash the aeration vessels, measurement cells and their inlet and outlet tubes at least three times with acetone in order to remove as much of the organic residue as possible. Rinsewith tap water.The cleanliness of the aeration vessels is paramount in achieving correct induction
