1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 17932:2011Palm oil Determinationof the deterioration ofbleachability index (DOBI)and carotene content (ISO17932:2011)BS EN ISO 17932:2011 BRITISH STANDARDNational forew
2、ordThis British Standard is the UK implementation of EN ISO17932:2011. It supersedes BS EN ISO 17932:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee AW/307, Oilseeds, animal and vegetable fats and oils andtheir by-products.A list of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 r
3、epresented 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 2011ISBN 978 0 580 70241 9ICS 67.200.10Compliance with a British Standard cannot confe
4、r immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 September 2011.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 17932 September 2011 ICS 67.200.10
5、 Supersedes EN ISO 17932:2007English Version Palm oil - Determination of the deterioration of bleachability index (DOBI) and carotene content (ISO 17932:2011) Huile de palme - Dtermination de la dtrioration de lindice de blanchiment (DOBI) et de la teneur en carotne (ISO 17932:2011) Palml - Bestimmu
6、ng des Bleichindex zur Beurteilung der Qualitt von rohem Palml (DOBI Deterioration of bleachability index) sowie des Carotingehaltes (ISO 17932:2011) This European Standard was approved by CEN on 14 September 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipu
7、late 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 obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European S
8、tandard 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-CENELEC Management Centre has the same status as the official versions. CEN members are the
9、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, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Swi
10、tzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No
11、. EN ISO 17932:2011: EBS EN ISO 17932:2011EN ISO 17932:2011 (E) 3 Foreword This document (EN ISO 17932:2011) has been prepared by Technical Committee ISO/TC 34 “Food products“ in collaboration with Technical Committee CEN/TC 307 “Oilseeds, vegetable and animal fats and oils and their by-products - M
12、ethods 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, at the latest by March 2012, and conflicting national standards shall be withdrawn at the
13、 latest by March 2012. 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 any or all such patent rights. This document supersedes EN ISO 17932:2007. According to the CE
14、N/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, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Li
15、thuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 17932:2011 has been approved by CEN as a EN ISO 17932:2011 without any modification. BS EN ISO 17932:2011ForewordISO (
16、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 which a technical commi
17、ttee 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 matters of electrotec
18、hnical 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 circulated to the member
19、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 responsible for identifying a
20、ny or all such patent rights.ISO 17932 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils.This second edition cancels and replaces the first edition (ISO 17932:2005), which has been technically revised.ISO 17932:2011(E) ISO 2011 All r
21、ights reserved iiiBS EN ISO 17932:2011BS EN ISO 17932:2011INTERNATIONAL STANDARD ISO 17932:2011(E)Palm oil Determination of the deterioration of bleachability index (DOBI) and carotene content1 ScopeThis International Standard specifies a method for the determination of the deterioration of bleachab
22、ility index (DOBI) of crude palm oil and the carotene content of crude or bleached palm oil and their fractions by spectrophotometric examination in the ultraviolet and visible range of the spectrum.2 Normative referencesThe following referenced documents are indispensable for the application of thi
23、s 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, Animal and vegetable fats and oils Preparation of test sampleISO/IEC 17025, General requirements for the competence of t
24、esting and calibration laboratoriesISO Guide 34, General requirements for the competence of reference material producers3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1deterioration of bleachability indexDOBIIDoBratio of the absorbance of the te
25、st portion at 446 nm to that at 269 nm, as determined spectrophotometrically in a 10 mm (1 cm) pathlength cellNOTE DOBI is expressed to one decimal place without a dimension.3.2carotene content of vegetable oilwcmass fraction of -carotene in oilNOTE The carotene content of vegetable oil is expressed
26、 in milligrams per kilogram.4 PrincipleA homogenized sample is dissolved in isooctane and the absorbance is measured spectrophotometrically at 446 nm and 269 nm. The DOBI value is the ratio of the absorbance at 446 nm to that at 269 nm. The test is a measure of the ease of refining crude palm oil. A
27、 low DOBI value can indicate difficulty in refining the oil to a low Lovibond colour. The absorbance at 446 nm is used for calculation of the carotene content.5 ReagentsWARNING Attention is drawn to the regulations which specify the handling of dangerous substances. Technical, organizational and per
28、sonal safety measures shall be followed. ISO 2011 All rights reserved 1BS EN ISO 17932:2011During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity.5.1 Solvent: isooctane (2,2,4-trimethylpentane)
29、, having an absorbance less than 0,12 at 230 nm and less than 0,05 at 250 nm against water, measured in a cell with a pathlength of 10 mm (1 cm).6 ApparatusThe glassware used for the determination shall be thoroughly cleaned and rinsed with the solvent (5.1) before use, so that it is free from impur
30、ities having an absorbance within the wavelength range of 220 nm to 500 nm.Usual laboratory apparatus and, in particular, the following.6.1 Spectrometer, capable of operating in the ultraviolet and visible range and using 10 mm (1 cm) pathlength quartz cells and preferably having a recording instrum
31、ent.Before use, it is recommended that the wavelength and absorbance scales of the spectrometer be checked as follows.a) Wavelength scale: This may be checked using a reference material consisting of an optical glass filter containing holmium oxide which has distinct absorption bands. The reference
32、material is designed for the verification and calibration of the wavelength scales of visible and ultraviolet spectrophotometers having nominal spectral bandwidths of 5 nm or less. The holmium glass filter is measured in the absorbance mode against an air blank over the wavelength range of 640 nm to
33、 240 nm. For each spectral bandwidth (0,10 0,25 0,50 1,00 1,50 2,00 and 3,00), a baseline correction is performed with an empty cell holder. The wavelengths of the spectral bandwidth are listed in the certificate of the reference material1). All procedures shall be implemented in accordance with ISO
34、/IEC 17025 and ISO Guide 34.b) Absorbance scale: Secondary calibration standards can be used to check the ordinate accuracy. The set of standards consisting of gray glass filters2)provide nominal absorbance, A, values of 0,3A, 0,5A, and 1,0A respectively. The ordinate readings of the filters are mea
35、sured at each of the selected wavelengths and the readings obtained compared with those listed in the certificate of the secondary calibration standards.Alternatively, prepare a 200 mg/l solution of potassium chromate3)in 0,05 mol/l potassium hydroxide solution. Transfer 25 ml of this solution to a
36、volumetric flask, capacity 500 ml, ISO 10421, class A, and make up to the mark with additional 0,05 mol/l potassium hydroxide solution. The absorbance of this solution, measured in a cell 10 mm thick at 275 nm against the 0,05 mol/l potassium hydroxide solution, should be 0,200 0,005.WARNING Potassi
37、um chromate is very toxic, dangerous to the environment and a carcinogen by inhalation. Attention is drawn to regulations which specify handling and disposal procedures for toxic and dangerous substances. Users should be aware of and comply with technical, organizational, and personal safety measure
38、s.6.2 Matched quartz cells, of pathlength 10 mm (1 cm), suitable for measurements at ultraviolet and visible wavelengths.6.3 Volumetric flask, capacity 25 ml, ISO 10421, class A.6.4 Analytical balance, capable of being read to the nearest 0,001 g.1) Starna Scientific Ltd () is an example of a suppli
39、er of suitable holmium filters and potassium dichromate sealed cell available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of these products.2) A suitable supplier is PerkinElmer Ltd. This information is given for
40、 the convenience of users of this document and does not constitute an endorsement by ISO of the supplier named.3) NIST 935a is an example of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IS
41、O of the product named.ISO 17932:2011(E)2 ISO 2011 All rights reservedBS EN ISO 17932:20117 SamplingSampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 55552.A representative sample should have been sent to the laboratory. It sho
42、uld not have been damaged or changed during transport or storage.Ensure that the sample is taken and stored away from strong light, kept cold and contained in completely filled glass containers, hermetically sealed with ground glass or waxed cork stoppers.8 Preparation of test samplePrepare the test
43、 sample in accordance with ISO 661.9 Procedure9.1 GeneralMelt the sample at 60 C to 70 C and homogenize thoroughly before taking a test portion. Filter through a fast filter paper Whatman No. 14) if the sample contains impurities and is not clear.9.2 Test portion and preparation of the test solution
44、Weigh, to the nearest 0,1 mg, about 0,1 g to 0,5 g of the test sample (Clause 8), sufficient to obtain absorbance values between 0,2 and 0,8, into a 25 ml volumetric flask (6.3).Dissolve the test portion in a few millilitres of isooctane (5.1) at ambient temperature and then make up to the mark with
45、 the same solvent. Mix thoroughly.9.3 DeterminationRinse a quartz cell (6.2) three times with the test solution (9.2). Fill the cell with the test solution and fill a second matched cell with isooctane (5.1). Measure the absorbance of the test solution against the solvent by means of the spectromete
46、r (6.1) at wavelengths 446 nm and 269 nm. If necessary, dilute the original test solution (9.2) to a measured volume and take further readings so that the observed absorptions are between (0,2 and 0,8) absorbance values.10 Calculation10.1 The deterioration of bleachability index (DOBI), IDoB, is cal
47、culated as follows:4) Example of a suitable product available commercially. This information is given for the convenience of users of this document 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.ISO 1793
48、2:2011(E) ISO 2011 All rights reserved 3BS EN ISO 17932:2011IAADoB446269=whereA446is the absorbance at 446 nm;A269is the absorbance at 269 nm.Express the results to one decimal place.10.2 Calculate the total carotene content, wc, of oil as -carotene, in milligrams per kilogram, using the following f
49、ormula:wAlc=383 where383 = 106/2 610, in which 2 610 is the percentage solution extinction coefficient of -carotene in isooctane at 446 nm;A is the observed difference in absorption, A, between the sample solution and the solvent (5.1);l is the pathlength, in centimetres, of the cell; is the concentration, in grams per 100 ml, used for absorption measurement.Express the results to the nearest whole number.11 Precision11.1 Interlaboratory testDetails of an interlaboratory test on the precision of the method fo
