DIN EN ISO 6647-2-2015 Rice - Determination of amylose content - Part 2 Routine methods (ISO 6647-2 2015) German version EN ISO 6647-2 2015《稻米 直链淀粉含量测定 第2部分 常规方法(ISO 6647-2-2015) 德.pdf

1、September 2015Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).I

2、CS 67.060!%F0:“2351323www.din.deDDIN EN ISO 6647-2Rice Determination of amylose content Part 2: Routine methods (ISO 6647-2:2015);English version EN ISO 6647-2:2015,English translation of DIN EN ISO 6647-2:2015-09Reis Bestimmung des Amylosegehalts Teil 2: Routineverfahren (ISO 6647-2:2015);Englische

3、 Fassung EN ISO 6647-2:2015,Englische bersetzung von DIN EN ISO 6647-2:2015-09Riz Dtermination de la teneur en amylose Partie 2: Mthodes de routine (ISO 6647-2:2015);Version anglaise EN ISO 6647-2:2015,Traduction anglaise de DIN EN ISO 6647-2:2015-09SupersedesDIN EN ISO 6647-2:2007-11www.beuth.deIn

4、case of doubt, the German-language original shall be considered authoritative.Document comprises 16 pages08.15 DIN EN ISO 6647-2:2015-09 2 A comma is used as the decimal marker. National foreword This document (EN ISO 6647-2:2015) has been prepared by Technical Committee ISO/TC 34 “Food products” (S

5、ecretariat: AFNOR, France/ABNT, Brazil), Subcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China) in collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was the DIN-Normenausschus

6、s Lebensmittel und landwirtschaftliche Produkte (DIN Standards Committee Food and Agricultural Products), Working Committee NA 057-05-06 AA Getreide und Getreideerzeugnisse. DIN EN ISO 6647 consists of the following parts, under the general title Rice Determination of amylose content: Part 1: Refere

7、nce method Part 2: Routine methods The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 1666 DIN EN ISO 1666 ISO 5725-1 DIN EN ISO 5725-1 ISO 5725-2 DIN EN ISO 5725-2 ISO 6647-1 DIN EN ISO 6647-1 ISO 24333 DIN EN ISO 24333 Amendments This st

8、andard differs from DIN EN ISO 6647-2:2007-11 as follows: a) the method has been revised and brought in line with the state of the art; b) 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

9、calibration curve. Previous editions DIN EN ISO 6647-2: 2007-11 DIN EN ISO 6647-2:2015-09 3 National Annex NA (informative) Bibliography DIN EN ISO 1666, Soil quality Determination of pore water pressure Tensiometer method DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and

10、results Part 1: General principles and definitions DIN ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method DIN EN ISO 6647-1, Rice Determination of amylose co

11、ntent Part 1: Reference method DIN EN ISO 24333, Cereals and cereal products Sampling DIN EN ISO 6647-2:2015-09 4 This page is intentionally blank EN ISO 6647-2May 2015 ICS 67.060 Supersedes EN ISO 6647-2:2007English Version Rice - Determination of amylose content - Part 2: Routine methods (ISO 6647

12、-2:2015) Riz - Dtermination 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 I

13、nternal 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 be obtained on application to the CEN-CENELEC Management Centre or to

14、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 to the CEN-CENELEC Management Centre has the same status as the official

15、 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, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Nor

16、way, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 664

17、7-2:2015 EEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNG2DIN EN ISO 6647-2:2015-09 EN ISO 6647-2:2015 (E) Contents Page Foreword . 3 1 Scope . 4 2 Normative references. 4 3 Terms and definitions 4 4 Pr

18、inciple 4 5 Reagents . 4 6 Apparatus 5 7 Sampling . 5 8 Procedure 6 8.1 Preparation of test samples 6 8.2 Test portion and preparation of the test solution . 6 8.3 Blank test 6 8.4 Preparation of the calibration graph 6 8.4.1 Preparation of the set of calibration solutions . 6 8.4.2 Colour developme

19、nt and spectrometric measurements 6 8.4.3 Plotting the calibration graph . 6 8.5 Determination . 6 9 Expression of results . 7 10 Precision . 7 10.1 Interlaboratory test . 7 10.2 Repeatability . 7 10.3 Reproducibility . 7 11 Test report . 7 Annex A (informative) Results of an interlaboratory test 8

20、Annex B (informative) Comparison of values from ISO 6647-2:2007 . 11 Bibliography 12 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 338 “Cereal and cereal products” the secretariat of which

21、 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 the latest by November 2015. Attention is drawn to the po

22、ssibility 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 to the CEN-CENELEC Internal Regulations, the national stand

23、ards 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, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lu

24、xembourg, 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 without any modification. “”3DIN EN ISO 6647-2:2015-09EN ISO 6

25、647-2:2015 (E)1 ScopeThis part of ISO 6647 specifies a simplified routine method for the determination of the amylose content of milled, 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 chromatogra

26、phy (SEC) are used as standards to generate the calibration curve.NOTE The use of standards calibrated by SEC is an approach to determine 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 nor

27、matively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 6647-1, Rice Determination of amylose content Part 1: Ref

28、erence methodISO 7301, Rice SpecificationISO 8466-1, Water quality Calibration and evaluation of analytical methods and estimation of performance characteristics Part 1: Statistical evaluation of the linear calibration function3 Terms and definitionsFor the purposes of this document, the terms and d

29、efinitions 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 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 ab

30、sorbance, at 620 nm or 720 nm of the colour complex formed, is then determined using a spectrophotometer.The amylose content of the sample 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).NO

31、TE Rice samples with certified amylose content according to ISO 6647-1 are used as standards.5 ReagentsAll the reagents used shall be of recognized analytical quality and the water used shall be distilled, or demineralised water, or water of equivalent purity.5.1 Ethanol, 95 % (v/v).4DIN EN ISO 6647

32、-2:2015-09 EN ISO 6647-2:2015 (E) 5.2 Sodium hydroxide, 1 mol/l solution.5.3 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

33、saturated solution. Add 0,200 g of iodine, weighed to the nearest 1 mg. When 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 ApparatusU

34、sual laboratory equipment and, in particular, the following:6.1 Grinder, capable 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 Spectrophot

35、ometer, with matching cells, usually of 1 cm path length, capable of measuring 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,

36、 1 ml, 5 ml, and 10 ml.6.9 Conical flask, 100 ml.6.10 Vortex mixer.7 SamplingIt 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 re

37、commended sampling method is given in ISO 24333.5DIN EN ISO 6647-2:2015-09EN ISO 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 preparatio

38、n of the test solutionWeigh 100 mg 0.5 mg of the test 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

39、,0 ml of sodium hydroxide solution (5.2) from a pipette 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).

40、Vortex (6.10), make up to volume with water, and then 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) instea

41、d of the test solution.8.4 Preparation of the calibration 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.

42、 Alternatively, create a set of standards from different 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 solu

43、tion into a series of five test tubes (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). 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

44、 by inverting several times.Measure the absorbance at 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

45、 the amylose content, expressed as a percentage by mass, 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

46、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 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 S

47、tandard and does not constitute an endorsement by ISO. Equivalent products may be used if they can be shown to lead to the same results.6DIN EN ISO 6647-2:2015-09 EN ISO 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 t

48、he blank (8.3), immediately after 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