EN ISO 3960-2010 8125 Animal and vegetable fats and oils - Determination of peroxide value - Iodometric (visual) endpoint determination (ISO 3960 2007 corrected version 2009-05-15).pdf

《EN ISO 3960-2010 8125 Animal and vegetable fats and oils - Determination of peroxide value - Iodometric (visual) endpoint determination (ISO 3960 2007 corrected version 2009-05-15).pdf》由会员分享，可在线阅读，更多相关《EN ISO 3960-2010 8125 Animal and vegetable fats and oils - Determination of peroxide value - Iodometric (visual) endpoint determination (ISO 3960 2007 corrected version 2009-05-15).pdf（16页珍藏版）》请在麦多课文档分享上搜索。

1、BS EN ISO 3960:2010ICS 67.200.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDAnimal and vegetable fats and oils Determination of peroxide value Iodometric (visual) endpoint determination (ISO 3960:2007, corrected version 2009-05-15)Copyright European Committe

2、e for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-This British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 May2010. BSI 2010ISBN 978 0 580 69813 2Amendments/co

3、rrigenda issued since publicationDate CommentsBS EN ISO 3960:2010National forewordThis British Standard is the UK implementation of EN ISO 3960:2010. Itis identical to ISO 3960:2007. It supersedes BS EN ISO 3960:2008 whichis withdrawn.The UK participation in its preparation was entrusted to Technica

4、lCommittee AW/307, Oil seeds, animal and vegetable fats and oils andtheir by products.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its

5、 correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EUROPEAN STANDARD NORME EUROP

6、ENNE EUROPISCHE NORM EN ISO 3960 April 2010 ICS 67.200.10 Supersedes EN ISO 3960:2008English Version Animal and vegetable fats and oils - Determination of peroxide value - Iodometric (visual) endpoint determination (ISO 3960:2007, corrected version 2009-05-15) Corps gras dorigines animale et vgtale

7、- Dtermination de lindice de peroxyde - Dtermination avec point darrt iodomtrique (ISO 3960:2007, version corrige 2009-05-15)Tierische und pflanzliche Fette und le - Bestimmung der Peroxidzahl - Iodometrische (visuelle) Endpunktbestimmung (ISO 3960:2007, korrigierte Fassung 2009-05-15) This European

8、 Standard was approved by CEN on 13 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 concern

9、ing 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

10、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,

11、 Lithuania, Luxembourg, Malta, 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

12、2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 3960:2010: ECopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from

13、IHS-,-,-BS EN ISO 3960:2010EN ISO 3960:2010 (E) 3 Foreword The text of ISO 3960:2007, corrected version 2009-05-15 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 3960:2010 by Technical C

14、ommittee 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

15、, 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

16、 any or all such patent rights. This document supersedes EN ISO 3960:2008. 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, De

17、nmark, 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 3960:2007, corrected ver

18、sion 2009-05-15 has been approved by CEN as a EN ISO 3960:2010 without any modification. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 3960:2007(E) ISO 2007 All rights rese

19、rved iiiForeword 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 w

20、hich 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

21、 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 c

22、irculated 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 resp

23、onsible for identifying any or all such patent rights. ISO 3960 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils. This fourth edition cancels and replaces the third edition (ISO 3960:2001), which has been technically revised. This c

24、orrected version of ISO 3960:2007 incorporates the following corrections: Introduction, lines 9 and 10, “greater than” and “less than or equal to” replace “” and “u”, respectively; Introduction, line 11, “milliequivalents” has become “meq” (twice); 5.6, final sentence, has been reedited to correct d

25、etails of blue colour formation; 6.6 now contains a readability figure of 0,000 1 g, not 0,001 g; 9.2.2, line 1, now refers to 0,001 g instead of 0,001 mg; 9.2.2, paragraph 4, now contains a calculation of factor, F, to replace that of the exact concentration, cstand, of the 0,01 N sodium thiosulfat

26、e solution; Clause 10 has been revised to incorporate factor, F, from the revised 9.2.2. BS EN ISO 3960:2010Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 3960:2007(E) iv IS

27、O 2007 All rights reservedIntroduction Over a period of many years, various methods have been developed for the determination of peroxides in fats and oils. The general principle of most of the methods is the liberation of iodine from potassium iodide in an acid medium. The method according to Wheel

28、er was standardized more than 50 years ago by different standardization bodies, and it is widely used to control commodities by producers, receivers and official laboratories. In national and international food legislation (including the Codex Alimentarius), acceptable limits for the peroxide values

29、 are often specified. Due to anomalies in the reproducibility of the results, it was noticed that there are slight differences between the standardized methods. A very important point is the dependence of the result on the amount of sample used for the determination. As the determination of the pero

30、xide value (PV) is a highly empirical procedure, ISO/TC 34/SC 11 has decided to fix the sample mass at 5 g for PV greater than 1, and at 10 g for PV less than or equal to 1, and to limit the applicability of this method to animal and vegetable fats and oils with peroxide values from 0 meq to 30 meq

31、of active oxygen per kilogram. The user of this International Standard should be aware that the results obtained can be slightly lower than with previous standards. BS EN ISO 3960:2010Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction

32、 or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD ISO 3960:2007(E) ISO 2007 All rights reserved 1Animal and vegetable fats and oils Determination of peroxide value Iodometric (visual) endpoint determination 1 Scope This International Standard specifies a method for the iod

33、ometric determination of the peroxide value of animal and vegetable fats and oils with a visual endpoint detection. The peroxide value is a measure of the amount of oxygen chemically bound to an oil or fat as peroxides, particularly hydroperoxides. The method is applicable to all animal and vegetabl

34、e fats and oils, fatty acids and their mixtures with peroxide values from 0 meq to 30 meq (milliequivalents) of active oxygen per kilogram. It is also applicable to margarines and fat spreads with varying water content. The method is not suitable for milk fats and is not applicable to lecithins. It

35、is to be noted that the peroxide value is a dynamic parameter, whose value is dependent upon the history of the sample. Furthermore, the determination of the peroxide value is a highly empirical procedure and the value obtained depends on the sample mass. It is stressed that, due to the prescribed s

36、ample mass, the peroxide values obtained can be slightly lower than those obtained with a lower sample mass. NOTE 1 A preferred method for the iodometric determination of the peroxide value for milk fats is specified in ISO 3976. NOTE 2 A method for the potentiometric determination of the peroxide v

37、alue is given in ISO 27107. 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

38、. ISO 661, Animal and vegetable fats and oils Preparation of test sample 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 peroxide value PV quantity of those substances in the sample, expressed in terms of active oxygen, that oxidize potassium

39、 iodide under the conditions specified in this International Standard NOTE The peroxide value is usually expressed in milliequivalents (meq) of active oxygen per kilogram of oil, but it may also be expressed (in SI units) as millimoles (mmol) of active oxygen per kilogram of oil. The value expressed

40、 in millimoles of active oxygen per kilogram is half that expressed in milliequivalents of active oxygen per kilogram. Multiplication of the peroxide value (meq of active oxygen per kg) by the equivalent mass of oxygen (equalling 8) gives the milligrams of active oxygen per kilogram of oil. BS EN IS

41、O 3960:2010Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ISO 3960:2007(E) 2 ISO 2007 All rights reserved4 Principle The test sample is dissolved in isooctane and glacial acetic

42、 acid, and potassium iodide is added. The iodine liberated by the peroxides is determined iodometrically (visually) with a starch indicator and a sodium thiosulfate standard solution. The endpoint of the titration is determined iodometrically (visually). 5 Reagents WARNING Attention is drawn to the

43、national regulations that specify the handling of hazardous substances and users obligations thereunder. Technical, organizational and personal safety measures shall be followed. Use only reagents of recognized analytical grade, unless otherwise specified. All reagents shall be free of dissolved oxy

44、gen. 5.1 Water, demineralized, boiled and cooled down to 20 C. 5.2 Glacial acetic acid, mass fraction of 100 %; degassed in an ultrasonic bath under vacuum or by purging with a current of pure and dry inert gas (carbon dioxide or nitrogen). 5.3 Isooctane, degassed in an ultrasonic bath under vacuum

45、or by purging with a current of pure and dry inert gas (carbon dioxide or nitrogen). 5.4 Glacial acetic acid/isooctane solution, prepared by mixing 60 ml of glacial acetic acid and 40 ml of isooctane (volume fraction of glacial acetic acid: = 60 ml/100 ml, and volume fraction of isooctane: = 40 ml/1

46、00 ml). The mixture is degassed in an ultrasonic bath under vacuum or by purging with a current of pure and dry inert gas (carbon dioxide or nitrogen). 5.5 Potassium iodide, free from iodine and iodates. 5.6 Saturated potassium iodide solution, mass concentration (KI) = 175 g/100 ml. Dissolve approx

47、imately 14 g of potassium iodide in approximately 8 g of freshly boiled water at room temperature. Make sure the solution remains saturated (undissolved crystals). Store in the dark and prepare freshly every day. Test the solution as follows: add two drops of starch solution to 0,5 ml of the potassi

48、um iodide in 30 ml of the glacial acetic acid/isooctane solution (5.4). If a blue colour is formed and if more than one drop of sodium thiosulfate standard solution (5.7) is needed to remove it, discard the potassium iodide solution. 5.7 0,1 N sodium thiosulfate standard solution, c(Na2S2O3) = 0,1 m

49、ol/l. Use only freshly boiled water for the preparation of this solution, possibly purged with nitrogen. This solution can be used for one month and is stored in an amber-stained bottle. 5.8 0,01 N sodium thiosulfate standard solution, c(Na2S2O3) = 0,01 mol/l (see 9.2). It is necessary to prepare this solution freshly from the