1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 6646:2011 Rice Determination of the potential milling yield from paddy and from husked riceBS ISO 6646:2011 BRITISH STANDARD National foreword This British Standard is
2、the UK implementation of ISO 6646:2011. It supersedes BS ISO 6646:2000, which is withdrawn. The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e A W / 4 , C e r e a l s a n d p u l s e s . A list of organizations represented on this committee can be obtained o
3、n request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 67549 2 ICS 67.060 Compliance with a British Standard cannot confer immunity from legal obligations. This Br
4、itish Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2011. Amendments issued since publication Date T e x t a f f e c t e dBS ISO 6646:2011Reference number ISO 6646:2011(E) ISO 2011INTERNATIONAL STANDARD ISO 6646 Third edition 2011-07-01 Rice Det
5、ermination of the potential milling yield from paddy and from husked rice Riz Dtermination des rendements dusinage partir du riz paddy et du riz dcortiqu BS ISO 6646:2011 ISO 6646:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publicati
6、on may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20
7、 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedBS ISO 6646:2011 ISO 6646:2011(E) ISO 2011 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation
8、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 committee. I
9、nternational 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. International Standards are drafted in accordance with
10、 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 bodies for voting. Publication as an International Standard requires approva
11、l 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 any or all such patent rights. ISO 6646 was prepared by Technical Committee
12、ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses. This third edition cancels and replaces the second edition (ISO 6646:2000), which has been technically revised. BS ISO 6646:2011 ISO 6646:2011(E) iv ISO 2011 All rights reservedIntroduction The milling yields obtained from abrasive tes
13、ting mills of the same model, although with differing adjustments, may vary more widely than those obtained from different types of abrasive testing mill. This International Standard specifies a method for the determination of milling yield, to ensure that results obtained by different operators usi
14、ng abrasive test mills are comparable. BS ISO 6646:2011 INTERNATIONAL STANDARD ISO 6646:2011(E) ISO 2011 All rights reserved 1Rice Determination of the potential milling yield from paddy and from husked rice 1 Scope This International Standard specifies a laboratory method for the determination of t
15、he yield of husked rice obtained from paddy or parboiled paddy (Oryza sativa L.), and for the determination of the yield of milled head rice obtained from paddy or parboiled paddy, or from husked rice or husked parboiled rice. This International Standard is only applicable to abrasive milling equipm
16、ent. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 712, Cereals and
17、cereal products Determination of moisture content Reference method ISO 7301, Rice Specification 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7301 and the following apply. 3.1 husked rice yield amount of husked rice obtained from paddy 3.2 milled r
18、ice yield amount of milled rice (head rice, broken kernels, and chips) obtained from paddy or husked rice 3.3 milled head rice yield amount of milled whole kernel and head rice obtained from paddy or husked rice 3.4 perfect kernel husked or milled kernel without any broken part which is not immature
19、 or malformed 4 Principle The husk is mechanically removed from paddy. The resultant husked rice is then weighed. Next, the bran and germ are mechanically removed from the husked rice to a fixed reduction in mass and the resulting milled head rice is weighed. BS ISO 6646:2011 ISO 6646:2011(E) 2 ISO
20、2011 All rights reserved5 Apparatus Usual laboratory apparatus and, in particular, the following. 5.1 Sample divider, conical sampler or multiple-slot sampler with distribution system. 5.2 Testing husker, suitable for removal of the husk from paddy without damaging the kernels. 5.3 Abrasive testing
21、mill, suitable for removal of the pericarp and germ from husked rice. 5.4 Tweezers. 5.5 Small bowls. 5.6 Balance, capable of being read to the nearest 0,01 g. 6 Sampling Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 24333 1
22、 . It is important the laboratory receive a truly representative sample which has not been damaged or changed during transport or storage. 7 Preparation of test sample The laboratory sample shall have a mass of not less than 1,5 kg. Carefully mix the laboratory sample to make it as homogeneous as po
23、ssible, then reduce it through a sample divider (5.1) to obtain the test sample. Determine the moisture content of the test sample in accordance with ISO 712. The acceptable range is a mass fraction of (13,0 1,0) %. If the moisture content is outside the acceptable range, the laboratory sample shoul
24、d be kept at ambient temperature and humidity for a sufficient period to obtain balanced moisture content within the specified range. 8 Procedure 8.1 Adjustment of equipment 8.1.1 Testing husker adjustment Adjustment of the test equipment shall be carried out prior to the determination. The testing
25、husker (5.2) shall be considered correctly adjusted when, subsequent to dehusking of rice samples with grain dimensions similar to those of the laboratory sample, the following are not present: a) husked rice with damage to the pericarp; b) grains of paddy or husked rice in the separated husk; c) hu
26、sk particles in the husked rice. BS ISO 6646:2011 ISO 6646:2011(E) ISO 2011 All rights reserved 38.1.2 Testing mill adjustment Adjust the testing mill (5.3) by milling rice samples of grain dimensions similar to those of the laboratory sample in order to remove a mass fraction, (f 0,5) %, of the hus
27、ked rice so that the difference, D, between the mass of milled head rice (head rice includes whole kernels) and the mass of milled whole kernels is needed to meet the requirements as follows: a) for grain with an average length of the test sample kernels 7,00 mm: D 3 %; b) for grain with an average
28、length of the test sample kernels 7,00 mm: D 5 %. The value of f shall be agreed by the parties involved. 8.2 Determination of husked rice yield (see Figure A.1) Take the test sample and divide it to give a portion suitable for the equipment. Pass through an aspiration apparatus to remove light matt
29、er, then spread the paddy and remove any extraneous matter. Weigh it to the nearest 0,01 g. A minimum of 200 g is recommended. Dehusk the paddy in the testing husker (5.2). Any grains of paddy that are not dehusked shall be manually separated from the husked rice, and dehusked once more. Then the re
30、sidual paddy shall be manually dehusked and added to the husked rice already present. Weigh the total yield of husked rice to the nearest 0,01 g. Carry out the test in duplicate. 8.3 Determination of milled head rice yield 8.3.1 Starting from paddy or parboiled paddy (see Figure A.2) 8.3.1.1 Proceed
31、 in accordance with 8.2 to obtain the husked rice. Divide the husked rice to give a portion suitable for the equipment. Weigh and record the mass to the nearest 0,01 g. A minimum of 100 g is recommended. 8.3.1.2 Thoroughly clean the testing mill (5.3). Introduce the husked rice sample and mill it fo
32、r the time necessary to remove the mass fraction (f 0,5) % of its total mass. Predetermine the milling time by trials on each test sample. Weigh the milled rice obtained and record the mass to the nearest 0,01 g. Separate the head rice from the broken kernels and place the two fractions in separate
33、bowls. Weigh the head rice and record the mass to the nearest 0,01 g. Carry out the test in duplicate. 8.3.2 Starting from husked rice or husked parboiled rice (see Figure A.3) 8.3.2.1 Take the test sample and divide it to give a portion suitable for the equipment. Pass through an aspiration apparat
34、us to remove light matter, then spread the husked rice and remove any extraneous matter. Weigh it to the nearest 0,01 g. A minimum of 100 g is recommended. 8.3.2.2 Continue in accordance with the procedure specified in 8.3.1.2. Carry out the test in duplicate. BS ISO 6646:2011 ISO 6646:2011(E) 4 ISO
35、 2011 All rights reserved9 Expression of results Calculate the results as quotients to four decimal places according to Table 1. Table 1 Calculation of milling yields Mass, m, of test portion starting from aParameter Paddy Husked rice Husked rice, y 0m y /m x1 Milled rice, y 1m 1 /m zm 1 /m zMilled
36、head rice, y 2m 2 /m zm 2 /m zaFor variable definitions, refer to the procedure schemes in Figure A.1 or A.2 for paddy, and Figure A.3 for husked rice. Express the yields as percentage mass fractions, with reference to the starting material, as follows: Potential yield of husked rice, y hy h= y 0 10
37、0 % Potential yield of milled rice, y my m= y 0 y 1 100 % Potential yield of milled head rice, y mhy mh= y 0 y 2 100 % Calculate the results for each category to two decimal places, and report them to the nearest 0,1 %. 10 Precision 10.1 Interlaboratory test Details of an interlaboratory test on the
38、 precision of the method are summarized for information in Annex B. The values derived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given. 10.2 Repeatability The absolute difference between two independent single test results, obtained us
39、ing the same method on identical 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 arithmetic mean of the values for the repeatability limit, r, from the interlaboratory study: a)
40、 for husked rice, 1 %; b) for milled head rice, 2 %. BS ISO 6646:2011 ISO 6646:2011(E) ISO 2011 All rights reserved 510.3 Reproducibility The absolute difference between two single test results, obtained using the same method on identical test material in different laboratories with different operat
41、ors using different equipment, will in not more than 5 % of cases be greater than the arithmetic mean of the values for the repeatability limit, R, from the interlaboratory study: a) for husked rice, 3 %; b) for milled head rice, 5 %. 11 Test report The test report shall contain at least the followi
42、ng information: a) all information necessary for the complete identification of the sample; b) the sampling method used, if known; c) the test method used, with reference to this International Standard (ISO 6646:2011); d) all operating details not specified in this International Standard, or regarde
43、d as optional, together with details of any incidents which may have influenced the test result(s); e) the test result(s) obtained; f) if the repeatability has been checked, the final quoted result obtained. BS ISO 6646:2011 ISO 6646:2011(E) 6 ISO 2011 All rights reservedAnnex A (normative) Procedur
44、e schemes Laboratory sample Test sample Test portion (m x 200 g) m y Mixing and reduction Moisture check (Clause 7) Dehusking (testing husker; see 5.2) Husked rice Removal of light and extraneous matterFigure A.1 Starting from paddy or parboiled paddy: yield of husked rice BS ISO 6646:2011 ISO 6646:
45、2011(E) ISO 2011 All rights reserved 7Laboratory sample Test sample Test portion (m x 200 g) m y Aliquot (m z 100 g) m 1 m 2 Mixing and reduction Moisture check (Clause 7) Removal of light and extraneous matter Husked rice Milling (testing mill; see 5.3) Milled rice Separation of head rice from rema
46、inder Milled head rice Dehusking (testing husker; see 5.2) Figure A.2 Starting from paddy or parboiled paddy: yield of husked rice, milled rice and milled head rice BS ISO 6646:2011 ISO 6646:2011(E) 8 ISO 2011 All rights reservedLaboratory sample Test sample Aliquot (m z 100 g) m 1 m 1 Mixing and re
47、duction Moisture check (Clause 7) Removal of light and extraneous matter Husked rice Milling (testing mill; see 5.3) Milled rice Separation of head rice from remainder Milled head rice m 2Figure A.3 Starting from husked rice or husked parboiled rice: yield of milled rice and milled head rice BS ISO
48、6646:2011 ISO 6646:2011(E) ISO 2011 All rights reserved 9Annex B (informative) Results of an interlaboratory test An interlaboratory study carried out by Henan University of Technology (China), with the participation of 10 laboratories, each of which carried out three determinations on seven differe
49、nt types of kernel, gave the statistical results, analysed in accordance with ISO 5725-1:1994 2and ISO 5725-2:1994 3 , shown in Tables B.1 and B.2. The f value was 10 %. Table B.1 Repeatability and reproducibility of y hRice sample Parameter GD JX HB JS LJ Number of laboratories retained after eliminating outliers 9 9 9 9 8 Mean value, g/100 g 79,5 79,3 79,1 83,9 81,7 Standard deviation of repeatability, s r , g/100 g 0,27 0,17 0,19 0,24 0,18 Coefficient of variation of repeatabilit
