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1、BRITISH STANDARD BS EN ISO 6647-1:2007 Rice Determination of amylose content Part 1: Reference method The European Standard EN ISO 6647-1:2007 has the status of a British Standard ICS 67.060 ? Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 20
2、07, Uncontrolled Copy, (c) BSI BS EN ISO 6647-1:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 BSI 2007 ISBN 978 0 580 55844 3 National foreword This British Standard is the UK implementation of EN ISO 6647-1:2007. The
3、 UK participation in its preparation was entrusted to Technical Committee AW/4, Cereals and pulses. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are re
4、sponsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontroll
5、ed Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 6647-1 September 2007 ICS 67.060 English Version Rice - Determination of amylose content - Part 1: Reference method (ISO 6647-1:2007) Riz - Dtermination de la teneur en amylose - Partie 1: Mthode de rfrence (ISO 6647-1:2007) R
6、eis - Bestimmung des Amylosegehalts - Teil 1: Referenzverfahren (ISO 6647-1:2007) This European Standard was approved by CEN on 27 August 2007. 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 n
7、ational standard without any alteration. Up-to-date lists and bibliographical references concerning 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
8、in any other language made by translation under the responsibility of a CEN member into its own 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, Cyprus, Czech Republic, Denmar
9、k, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATI
10、ON EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6647-1:2007: E Licensed Copy: London South Bank University, London South Bank Universi
11、ty, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Foreword This document (EN ISO 6647-1:2007) has been prepared by Technical Committee ISO/TC 34 “Agricultural food products“ in collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products“, the secretariat of which i
12、s 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 2008, and conflicting national standards shall be withdrawn at the latest by March 2008. According to the CEN/CENELEC Interna
13、l Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta
14、, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6647-1:2007 has been approved by CEN as a EN ISO 6647-1:2007 without any modification. EN ISO 6647-1:2007 Licensed Copy: London South Bank Unive
15、rsity, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Reference number ISO 6647-1:2007(E) INTERNATIONAL STANDARD ISO 6647-1 First edition 2007-09-01 Rice Determination of amylose content Part 1: Reference method Riz Dtermination de la teneur en amylose P
16、artie 1: Mthode de rfrence EN ISO 6647-1:2007 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Un
17、controlled Copy, (c) BSI iii Contents Page Foreword iv 1 Scope 1 2 Normative references1 3 Terms and definitions .1 4 Principle2 5 Reagents.2 6 Apparatus .3 7 Sampling.4 8 Procedure .4 8.1 Preparation of test sample4 8.2 Test portion and preparation of the test solution 4 8.3 Preparation of the blan
18、k solution.4 8.4 Preparation of the calibration graph4 8.5 Determination.5 9 Expression of results 5 10 Precision.6 10.1 Interlaboratory test6 10.2 Repeatability.6 10.3 Reproducibility.6 11 Test report6 Annex A (informative) Determination of the quality of the potato amylose standard7 Annex B (infor
19、mative) Example of a flow injection analyser (FIA) for the determination of amylose9 Annex C (informative) Results of an interlaboratory test10 Bibliography12 EN ISO 6647-1:2007 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolle
20、d Copy, (c) BSI iv Foreword 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 su
21、bject for which 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 (
22、IEC) on all 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 commi
23、ttees are circulated 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 b
24、e held responsible for identifying any or all such patent rights. ISO 6647-1 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses. This edition of ISO 6647-1, together with ISO 6647-2:2007, cancels and replaces ISO 6647:1987, which has been technically
25、revised. ISO 6647 consists of the following parts, under the general title Rice Determination of amylose content: Part 1: Reference method Part 2: Routine methods EN ISO 6647-1:2007 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontr
26、olled Copy, (c) BSI 1 Rice Determination of amylose content Part 1: Reference method 1 Scope This part of ISO 6647 specifies a reference method for the determination of the amylose content of milled rice, non-parboiled. The method is applicable to rice with an amylose mass fraction higher than 5 %.
27、This part of ISO 6647 can also be used for husked rice, maize, millet and other cereals if the extension of this scope has been validated by the user. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edit
28、ion cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 712, Cereals and cereal products Determination of moisture content Routine reference method ISO 7301, Rice Specification ISO 8466-1, Water quality Calibration and evaluati
29、on of analytical methods and estimation of performance characteristics Part 1: Statistical evaluation of the linear calibration function ISO 15914, Animal feeding stuffs Enzymatic determination of total starch content 3 Terms and definitions For the purposes of this document, the terms and definitio
30、ns given in ISO 7301 and the following apply. 3.1 amylose polysaccharide constituent of starch, the macromolecules of which have glucose units linked in a predominantly linear structure 3.2 amylopectin polysaccharide constituent of starch, the macromolecules of which have glucose units linked in a b
31、ranched structure EN ISO 6647-1:2007 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 4 Principle Rice is ground to a very fine flour to break up the endosperm structure in order to aid complete dispersion and
32、 gelatinization; the flour is then defatted. A test portion is dispersed in a sodium hydroxide solution, to an aliquot portion of which an iodine solution is added. The absorbance, at 720 nm, of the colour complex formed is then determined using a spectrophotometer. The amylose mass fraction of the
33、sample is then read from a calibration graph, which is prepared using mixtures of potato amylose and amylopectin to make allowance for the effect of amylopectin on the colour of the amyloseiodine complex of the test solution. NOTE The method actually determines the affinity of amylose for iodine. Th
34、e determination is made at 720 nm to minimize interfering effects of amylopectin. 5 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water or water of equivalent purity. 5.1 Methanol, a volume fraction of 85 %. 5.2 Ethanol, a volum
35、e fraction of 95 %. 5.3 Sodium hydroxide dispersal solutions. 5.3.1 Sodium hydroxide, 1 mol/l solution. 5.3.2 Sodium hydroxide, 0,09 mol/l solution. 5.4 Deproteination solutions 5.4.1 Detergent solution Dissolve sodium dodecylbenzene sulfonate corresponding to a concentration of 20 g/l. Just before
36、use, add sodium sulfite to a final concentration of 2 g/l. 5.4.2 Sodium hydroxide, for protein removal, 3 g/l solution. 5.5 Acetic acid, 1 mol/l solution. 5.6 lodine 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
37、form a 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 (6.6), make up to volume with water and mix. Prepare a fresh solution on each day of use and protect it from light. 5.7
38、Standard potato amylose suspension, free of amylopectin, 1 g/l. 5.7.1 Defat the potato amylose by refluxing with methanol (5.1) for 4 h to 6 h in an extractor at a rate of 5 to 6 droplets per second. The potato amylose should be pure and should be tested by amperometric or potentiometric titration.
39、Some commercial preparations are impure and would give erroneously high results for the amylose mass fraction of rice samples. Pure amylose should bind 19 % to 20 % of its own mass of iodine. For checking the purity of amylose, see Annex A. EN ISO 6647-1:2007 Licensed Copy: London South Bank Univers
40、ity, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 5.7.2 Spread the defatted potato amylose on a tray and leave for 2 days to allow evaporation of residual methanol and for moisture content equilibrium to be reached. Treat the amylopectin (5.8) and th
41、e test samples (8.1) in the same way. 5.7.3 Weigh (6.9) 100 mg 0,5 mg of the defatted and conditioned potato amylose into a 100 ml conical flask (6.8). Carefully add 1 ml of ethanol (5.2), rinsing down any potato amylose adhering to the walls of the flask. Add 9,0 ml of 1 mol/l sodium hydroxide solu
42、tion (5.3.1) and mix. Then heat the mixture on a boiling water bath (6.7) for 10 min to disperse the potato amylose. Allow to cool to room temperature and transfer into a 100 ml volumetric flask (6.6). Make up to volume with water and mix vigorously. 1 ml of this standard suspension contains 1 mg of
43、 potato amylose. When the test samples, the amylose and the amylopectin are conditioned in the same environment, no correction for moisture content is necessary and the results are obtained on a dry milled rice basis. If the test samples and the standards are not prepared under the same conditions,
44、the moisture content of both the samples and the standards has to be determined as specified in ISO 712 and the results should be corrected accordingly. 5.8 Standard amylopectin suspension, 1 g/l. Prepare from milled glutinous (waxy) rice with a starch content known to consist of at least 99 % by ma
45、ss of amylopectin. Steep the milled glutinous rice and blend in a suitable laboratory blender (6.1) to a finely divided state. Remove protein by exhaustive extraction with detergent solution (5.4.1), or, alternatively, with sodium hydroxide solution (5.4.2), wash and then defat by refluxing with met
46、hanol (5.1) as described in 5.7.1. Spread the deproteinated and defatted amylopectin on a tray and leave for 2 days to allow evaporation of residual methanol and for moisture content equilibrium to be reached. Carry out the procedure given in 5.7.3, but with amylopectin instead of amylose. 1 ml of t
47、his standard suspension contains 1 mg of amylopectin. The iodine binding capacity of amylopectin should be less than 0,2 % (see Annex A). 6 Apparatus The usual laboratory apparatus and, in particular, the following. 6.1 Laboratory blender. 6.2 Grinder, capable of reducing uncooked milled rice to flo
48、ur which will pass through a 150 m to 180 m (100 mesh to 80 mesh) sieve. A cyclone mill with 0,5 mm screen is recommended. 6.3 Sieve, size 150 m to 180 m (100 mesh to 80 mesh). 6.4 Spectrophotometer, with matching cells, usually of pathlength 1 cm, capable of measuring absorbance at 720 nm. 6.5 Extr
49、action apparatus, capable of refluxing samples with methanol at a rate of 5 to 6 droplets per second. 6.6 Volumetric flasks, 100 ml. 6.7 Boiling water bath. 6.8 Conical flasks, 100 ml. EN ISO 6647-1:2007 Licensed Copy: London South Bank University, London South Bank University, Fri Oct 05 02:46:14 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 6.9 Analytical balance, capable of weighing to the nearest 0,000 1 g. 7 Sampling A representative sample should have been s