1、BSI Standards PublicationBS EN ISO 3657:2013Animal and vegetable fatsand oils Determinationof saponification value (ISO3657:2013)BS EN ISO 3657:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO 3657:2013.It supersedes BS EN ISO 3657:2003 which is withdraw
2、n.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oilseeds, animal and vegetable fats and oils andtheir 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 th
3、e necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 78236 7ICS 67.200.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standar
4、d was published under the authority of theStandards Policy and Strategy Committee on 31 July 2013.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 3657 July 2013 ICS 67.200.10 Supersedes EN ISO 3657:2003English Version Animal and vegetable
5、 fats and oils - Determination of saponification value (ISO 3657:2013) Corps gras dorigines animale et vgtale - Dtermination de lindice de saponification (ISO 3657:2013) Tierische und pflanzliche Fette und le - Bestimmung der Verseifungszahl (ISO 3657:2013) This European Standard was approved by CEN
6、 on 5 July 2013. 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
7、 be obtained on application to the CEN-CENELEC 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 t
8、o the CEN-CENELEC 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland,
9、 Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Av
10、enue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 3657:2013: EBS EN ISO 3657:2013EN ISO 3657:2013 (E) 3 Foreword This document (EN ISO 3657:2013) has been prepared by Technical Committee ISO/T
11、C 34 “Food products“ in collaboration with 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 national standard, either
12、 by publication of an identical text or by endorsement, at the latest by January 2014, and conflicting national standards shall be withdrawn at the latest by January 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or
13、 CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 3657:2003. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria,
14、Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Sw
15、itzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 3657:2013 has been approved by CEN as EN ISO 3657:2013 without any modification. BS EN ISO 3657:2013ISO 3657:2013(E) ISO 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and def
16、initions . 14 Principle 15 Reagents 16 Apparatus . 27 Sampling 28 Preparation of the test sample . 29 Procedure. 39.1 Test portion 39.2 Determination . 39.3 Blank test . 310 Expression of results 311 Precision . 411.1 Results of interlaboratory test . 411.2 Repeatability . 411.3 Reproducibility . 41
17、2 Test report . 4Annex A (informative) Results of an interlaboratory test 5Annex B (informative) Calculation of saponification value from fatty acid composition data 6Bibliography .10BS EN ISO 3657:2013ISO 3657:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide fe
18、deration 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 which a technical committee has been established has the right to be represented on that com
19、mittee. 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 matters of electrotechnical standardization.The procedures used to develop this document a
20、nd those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Pa
21、rt 2, www.iso.org/directives.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 responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the do
22、cument will be in the Introduction and/or on the ISO list of patent declarations received, www.iso.org/patents.Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.The committee responsible for this document is ISO/TC 34, Food
23、products, Subcommittee SC 11, Animal and vegetable fats and oils.This fourth edition cancels and replaces the third edition (ISO 3657:2002), which has been technically revised.iv ISO 2013 All rights reservedBS EN ISO 3657:2013INTERNATIONAL STANDARD ISO 3657:2013(E)Animal and vegetable fats and oils
24、Determination of saponification value1 ScopeThis International Standard specifies a method for the determination of the saponification value of animal and vegetable fats and oils. The saponification value is a measure of the free and esterified acids present in fats and fatty acids.The method is app
25、licable to refined and crude vegetable and animal fats.If mineral acids are present, the results given by this method are not interpretable unless the mineral acids are determined separately.The saponification value can also be calculated from fatty acid data obtained by gas liquid chromatography an
26、alysis as given in Annex B. For this calculation, it is necessary to be sure that the sample does not contain major impurities or is thermally degraded.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its applic
27、ation. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 661, Animal and vegetable fats and oils Preparation of test sample3 Terms and definitionsFor the purposes of this document, the fo
28、llowing terms and definitions apply.3.1saponification valuenumber of milligrams of potassium hydroxide required for the saponification of 1 g of the product testedNote 1 to entry: The saponification value is a dimensionless quantity. The usual abbreviation is SV.4 PrincipleThe test sample is saponif
29、ied by boiling under reflux with an excess of ethanolic potassium hydroxide, followed by titration of the excess potassium hydroxide with standard volumetric hydrochloric acid solution.5 ReagentsUse only reagents of recognized analytical grade, and distilled or demineralized water of equivalent puri
30、ty.5.1 Ethanol, volume fraction = 95 %. ISO 2013 All rights reserved 1BS EN ISO 3657:2013ISO 3657:2013(E)5.2 Potassium hydroxide, c(KOH) = 0,5 mol/l solution in ethanol.This solution shall be colourless or straw yellow. A stable colourless solution can be prepared by either of the following procedur
31、es.a) Reflux 1 l of ethanol (5.1) with 8 g of potassium hydroxide and 5 g of aluminium pellets for 1 h, then distil immediately. Dissolve the required amount of potassium hydroxide (approximately 35 g) in the distillate. Allow to stand for several days, then decant the clear supernatant liquid from
32、the precipitated potassium carbonate into a brown-glass stock bottle.b) Add 4 g of aluminium tert-butylate to 1 l of ethanol and allow the mixture to stand for several days. Decant the supernatant liquid and dissolve in it the required amount of potassium hydroxide. Allow to stand for several days,
33、and then decant the clear supernatant liquid from the precipitated potassium carbonate into a brown-glass stock bottle.5.3 Hydrochloric acid, standard volumetric solution, c(HCl) = 0,5 mol/l.5.4 Phenolphthalein solution, = 0,1 g/100 ml in ethanol (5.1).5.5 Alkali blue 6B solution, = 2,5 g/100 ml in
34、ethanol (5.1).5.6 Boiling aids.6 ApparatusUsual laboratory apparatus and, in particular, the following.6.1 Conical flask, of 250 ml capacity, made of alkali-resistant glass and having a ground neck.6.2 Reflux condenser, with a ground glass joint which fits the conical flask (6.1).6.3 Heating device
35、(e.g. a water-bath, electric hot-plate or other suitable apparatus). A naked flame is not suitable.6.4 Burette, capacity 50 ml, graduated in 0,1 ml divisions or automatic burette.6.5 Pipette, capacity 25 ml or an automatic pipette.6.6 Analytical balance, readability 0,000 1 g, weighing precision 0,0
36、01 g.7 SamplingSampling is not part of this method specified in this International Standard. A recommended sampling method is given in ISO 5555.It is important that the laboratory receive a truly representative sample which has not been damaged or changed during transport or storage.8 Preparation of
37、 the test samplePrepare the test sample in accordance with ISO 661.The test samples are carefully mixed and filtered if visible impurities are present; if filtration is necessary, this shall be mentioned in the test report.2 ISO 2013 All rights reservedBS EN ISO 3657:2013ISO 3657:2013(E)9 Procedure9
38、.1 Test portionWeigh, to the nearest 5 mg, approximately 2 g of the test sample (Clause 8) into a conical flask (6.1).The test portion of 2 g has been determined on the basis of saponification values of 170 to 200. For other saponification values, the mass should be altered accordingly so that appro
39、ximately half the ethanolic potassium hydroxide solution is neutralized. Recommendations for the mass of the test portion are given in Table 1.Table 1 Mass of test portionExpected saponification value Mass of test portion150 to 200 2,2 to 1,8 g200 to 250 1,7 to 1,4 g250 to 300 1,3 to 1,2 g300 1,1 to
40、 1,0 g9.2 Determination9.2.1 Using a pipette (6.5), add to the test portion 25,0 ml of the ethanolic potassium hydroxide solution (5.2) and some boiling aids (5.6). Connect the reflux condenser (6.2) to the flask, place the flask on the heating device (6.3) and boil gently, shaking from time to time
41、, for 60 min or for 2 h in the case of oils and fats having a high melting point and which are difficult to saponify.9.2.2 Add to the hot solution 0,5 ml to 1 ml of the phenolphthalein solution (5.4) and titrate with the standard volumetric hydrochloric acid solution (5.3) until the pink colour of t
42、he indicator just disappears. If the solution is strongly coloured, use 0,5 ml to 1 ml of alkali blue 6 B solution (5.4).9.3 Blank testCarry out a blank test following the procedure specified in 9.2, using another 25,0 ml of the ethanolic potassium hydroxide solution (5.2) but omitting the test port
43、ion.10 Expression of resultsThe saponification value Isis given by the equationIVV cms56,1=()01whereV0is the volume, in millilitres, of the standard volumetric hydrochloric acid solution (5.3) used for the blank test;V1is the volume, in millilitres, of the standard volumetric hydrochloric acid solut
44、ion (5.3) used for the determination;c is the exact concentration, in moles per litre, of the standard volumetric hydrochloric acid solution (5.3);m is the mass, in grams, of the test portion (9.1). ISO 2013 All rights reserved 3BS EN ISO 3657:2013ISO 3657:2013(E)Take as the result the arithmetic me
45、an of the two determinations, provided that the requirement for repeatability (Clause 11) is satisfied.Express the result as a whole number.11 Precision11.1 Results of interlaboratory testAn interlaboratory test, carried out at the international level in 2000 by DIN, in which 22 laboratories partici
46、pated, each of which carried out two determinations on each sample, gave the statistical results (evaluated in accordance with ISO 5725-12and ISO 5725-23) shown in Table A.1.11.2 RepeatabilityThe absolute difference between two independent single test results, obtained using the same method in ident
47、ical test material in the same laboratory by the same operator using the same equipment within a short interval of time, will in not more than 5 % of cases be greater than the repeatability limit r given in Table A.1.11.3 ReproducibilityThe absolute difference between two single test results, obtain
48、ed using the same method in identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than the reproducibility limit R given in Table A.1.12 Test reportThe test report shall contain at least the following infor
49、mation:a) all information necessary for the complete identification of the sample;b) the sampling method used, if known;c) whether filtration of test sample(s) was necessary;d) the test method used, with reference to this International Standard (ISO 3657:2013);e) a statement of which indicator has been used, 5.4 or 5.5;f) all operating details not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s);g) the test result(s) obtained, or if the re
