BS EN ISO 6647-2-2015 Rice Determination of amylose content Routine methods《稻米 直链淀粉含量的测定 常规方法》.pdf

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1、BSI Standards PublicationBS EN ISO 6647-2:2015Rice Determination ofamylose contentPart 2: Routine methodsBS EN ISO 6647-2:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO6647-2:2015. It supersedes BS EN ISO 6647-2:2007 which iswithdrawn.The UK participat

2、ion in its preparation was entrusted to TechnicalCommittee AW/4, Cereals and pulses.A list of organizations represented 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 c

3、orrectapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 74416 7ICS 67.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy

4、 Committee on 31 May 2015.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 6647-2 May 2015 ICS 67.060 Supersedes EN ISO 6647-2:2007English Version Rice - Determination of amylose content - Part 2: Routine methods (ISO 6647-2:2015) Riz - Dt

5、ermination de la teneur en amylose - Partie 2: Mthodes de routine (ISO 6647-2:2015) Reis - Bestimmung des Amylosegehalts - Teil 2: Routineverfahren (ISO 6647-2:2015) This European Standard was approved by CEN on 7 February 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulatio

6、ns 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 be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. T

7、his 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 to the CEN-CENELEC Management Centre has the same status as the official versions. CEN me

8、mbers 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, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Port

9、ugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any f

10、orm and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6647-2:2015 EBS EN ISO 6647-2:2015EN ISO 6647-2:2015 (E) 3 Foreword This document (EN ISO 6647-2:2015) has been prepared by Technical Committee ISO/TC 34 “Food products“ in collaboration with Technical Committee CEN/TC

11、 338 “Cereal and cereal products” 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 November 2015, and conflicting national standards shall be withdrawn at

12、 the latest by November 2015. 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 6647-2:2007. According t

13、o 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, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greec

14、e, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 6647-2:2015 has been approved by CEN as EN ISO 6647-2:2015 with

15、out any modification. BS EN ISO 6647-2:2015ISO 6647-2:2015(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reagents 16 Apparatus . 27 Sampling 28 Procedure. 38.1 Preparation of test samples . 38.2 Test portion and preparation of the test solution . 38.3 Blan

16、k test . 38.4 Preparation of the calibration graph 38.4.1 Preparation of the set of calibration solutions 38.4.2 Colour development and spectrometric measurements . 38.4.3 Plotting the calibration graph . 38.5 Determination . 39 Expression of results 410 Precision . 410.1 Interlaboratory test. 410.2

17、 Repeatability . 410.3 Reproducibility . 411 Test report . 4Annex A (informative) Results of an interlaboratory test 5Annex B (informative) Comparison of values from ISO 6647-2:2007 8Bibliography 9 ISO 2015 All rights reserved iiiContents PageBS EN ISO 6647-2:2015ISO 6647-2:2015(E)ForewordISO (the I

18、nternational 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 committee

19、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 electrotechnica

20、l standardization.The procedures used to develop this document and 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 a

21、ccordance with the editorial rules of the ISO/IEC Directives, Part 2 (see 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. Det

22、ails of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an e

23、ndorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee res

24、ponsible for this document is ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses.This second edition cancels and replaces the first edition (ISO 6647-2:2007), of which it constitutes a minor revision.ISO 6647 consists of the following parts, under the general title Rice Determination of

25、 amylose content: Part 1: Reference method Part 2: Routine methodsiv ISO 2015 All rights reservedBS EN ISO 6647-2:2015Rice Determination of amylose content Part 2: Routine methods1 ScopeThis part of ISO 6647 specifies a simplified routine method for the determination of the amylose content of milled

26、, non-parboiled rice in the range from 1 % to 30 %. Rice samples for which the amylose content has been determined by the reference method size exclusion chromatography (SEC) are used as standards to generate the calibration curve.NOTE The use of standards calibrated by SEC is an approach to determi

27、ne the true amylose content and decreases the conversion errors of this part of ISO 6647.12 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. F

28、or undated references, the latest edition of the referenced document (including any amendments) applies.ISO 6647-1, Rice Determination of amylose content Part 1: Reference methodISO 7301, Rice SpecificationISO 8466-1, Water quality Calibration and evaluation of analytical methods and estimation of p

29、erformance characteristics Part 1: Statistical evaluation of the linear calibration function3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 6647-1 and ISO 7301 apply.4 PrincipleRice is ground to a very fine flour to break up the endosperm structure in

30、 order to aid complete dispersion and gelatinisation. A test portion is dispersed in sodium hydroxide solution, then an aliquot is mixed with iodine solution. The absorbance, at 620 nm or 720 nm of the colour complex formed, is then determined using a spectrophotometer.The amylose content of the sam

31、ple is then read from a calibration graph, which is prepared using rice samples with known amylose content, determined using the reference method (see ISO 6647-1).NOTE Rice samples with certified amylose content according to ISO 6647-1 are used as standards.5 ReagentsAll the reagents used shall be o

32、f recognized analytical quality and the water used shall be distilled, or demineralised water, or water of equivalent purity.5.1 Ethanol, 95 % (v/v).INTERNATIONAL STANDARD ISO 6647-2:2015(E) ISO 2015 All rights reserved 1BS EN ISO 6647-2:2015ISO 6647-2:2015(E)5.2 Sodium hydroxide, 1 mol/l solution.5

33、.3 Sodium hydroxide, 0,09 mol/l solution.5.4 Acetic acid, 1 mol/l solution.5.5 Iodine solution.Weigh, to the nearest 5 mg, 2,000 g of potassium iodide in a weighing bottle fitted with a stopper. Add sufficient water to form a saturated solution. Add 0,200 g of iodine, weighed to the nearest 1 mg. Wh

34、en all the iodine has dissolved, transfer the solution quantitatively to a 100 ml volumetric flask (6.4), make up to volume with water, and mix.Prepare a fresh solution on each day of use and protect it from light.6 ApparatusUsual laboratory equipment and, in particular, the following:6.1 Grinder, c

35、apable of reducing uncooked milled rice to flour which will pass through a 150 m to 180 m (80 to 100 Mesh) sieve. A cyclone mill with 0,5 mm screen is recommended.6.2 Sieve, size 150 m to 180 m (80 to 100 Mesh).6.3 Spectrophotometer, with matching cells, usually of 1 cm path length, capable of measu

36、ring absorbance at 600 nm - 720 nm, and cuvettes.6.4 Volumetric flasks, 100 ml.6.5 Boiling water bath.6.6 Analytical balance, capable of weighing to the nearest 0,000 1 g.6.7 Test tubes, 20 ml.6.8 Pipettes, capacity of 0,2 ml, 1 ml, 5 ml, and 10 ml.6.9 Conical flask, 100 ml.6.10 Vortex mixer.7 Sampl

37、ingIt is important that the laboratory receives a sample which is truly representative and has not been damaged or changed during transport or storage.Sampling is not part of the method specified in this part of ISO 6647. A recommended sampling method is given in ISO 24333.2 ISO 2015 All rights rese

38、rvedBS EN ISO 6647-2:2015ISO 6647-2:2015(E)8 Procedure8.1 Preparation of test samplesIn the grinder (6.1), grind at least 10 g of milled rice of each sample to very fine flour which will pass through the sieve (6.2).8.2 Test portion and preparation of the test solutionWeigh 100 mg 0.5 mg of the test

39、 sample into a 100 ml conical flask (6.9). To this test portion, carefully add 1,0 ml of ethanol (5.1) using a pipette, washing down any of the test portion adhering to the side of the flask. Shake slightly in order to wet all of the sample. Add 9,0 ml of sodium hydroxide solution (5.2) from a pipet

40、te and mix. Disperse starch completely by either heating the mixture in a boiling water bath (6.5) for 10 min or by standing overnight in covered flasks. Allow cooling to room temperature (if boiled) and transfer to 100 ml volumetric flask (6.4). Vortex (6.10), make up to volume with water, and then

41、 vortex again (6.10).8.3 Blank testCarry out a blank test in parallel with the determination, by the same procedure, using the same quantities of all the reagents as in the determination, but using 0,50 ml of sodium hydroxide solution (5.3) instead of the test solution.8.4 Preparation of the calibra

42、tion graph8.4.1 Preparation of the set of calibration solutionsUse five calibrated rice samples1), with a distribution of amylose content from 0 % to 30 %, and for which the amylose content has been certified by the reference method in ISO 6647-1. Alternatively, create a set of standards from differ

43、ent rice varieties calibrated against a standard curve made from the calibrated standards.Prepare the calibration solutions as in 8.1 and 8.2.8.4.2 Colour development and spectrometric measurementsPipette a 0,50 ml aliquot of each calibration solution into a series of five test tubes (6.7). Add 5,00

44、 ml of water, 0,10 ml of acetic acid (5.4), and 0,20 ml of iodine solution (5.5). Place an additional 4,20 ml of water into the tube to make the volume of the reaction mixture up to 10,00 ml. Cover the tube and mix well on a vortex mixer (6.10) or by inverting several times.Measure the absorbance at

45、 either 620 nm or 720 nm (choose the wavelength used in ISO 6647-1) against the blank (8.3), immediately after mixing, using the spectrophotometer (6.3).8.4.3 Plotting the calibration graphPrepare a calibration graph by plotting absorbance against the amylose content, expressed as a percentage by ma

46、ss, in the milled rice on the dry basis.8.5 DeterminationPipette a 0,50 ml aliquot of the test solution (8.2) into a test tube (6.7). Add 5,00 ml of water, 0,10 ml of acetic acid (5.4), and 0,20 ml of iodine solution (5.5). Put an additional 4,20 ml of water into the tube to make the volume of the r

47、eaction mixture up to 10,00 ml. Cover the tube and mix well on a vortex mixer 1) Calibrated rice samples can be obtained from the International Rice Research Institute. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO

48、. Equivalent products may be used if they can be shown to lead to the same results. ISO 2015 All rights reserved 3BS EN ISO 6647-2:2015ISO 6647-2:2015(E)(6.10) for 2 min or by inverting at least three times. Measure the absorbance at either 620 nm or 720 nm against the blank (8.3), immediately after

49、 mixing, using the spectrometer (6.3). Ensure that the standards and test solutions are measured at the same wavelength, either 620 nm or 720 nm, and in the same run.Carry out two determinations on separate test portions taken from the same test sample.NOTE If double determinations are made, based on two independent preparations of the sample (8.1), this should be noted in the test report.9 Expression of resultsThe amylose content, expressed as a percentage by mass on dry basis, is obtained by referring the absorbance (8.5) to the calib