1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 6646:2011Rice Determination of thepotential milling yield frompaddy and from husked riceBS ISO 6646:2011 BRITISH STANDARDNational forewordThis British Standard is the UK i
2、mplementation 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 It supersedes BS ISO 6646:2000, which is withdrawn.The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e A W / 4 , C e r e a l s a n d p u l s e s .A list of organizations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 on request
3、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 British Standa
4、rd was published under the authority of the Standards Policy and Strategy Committee on 31 July 2011.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 6646:2011Reference numberISO 6646:2011(E)ISO 2011INTERNATIONAL STANDARD ISO6646Third edition2011-07-01Rice Determination of the po
5、tential milling yield from paddy and from husked rice Riz Dtermination des rendements dusinage partir du riz paddy et du riz dcortiqu BS ISO 6646:2011ISO 6646:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
6、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 Tel. + 41 22 749 01
7、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 6646:2011ISO 6646:2011(E) ISO 2011 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards
8、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. International organizat
9、ions, 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 the rules given in th
10、e 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 approval by at least 75 % of
11、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 ISO/TC 34, Food produc
12、ts, 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 6646:2011ISO 6646:2011(E) iv ISO 2011 All rights reservedIntroduction The milling yields obtained from abrasive testing mills of the same
13、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 using abrasive test mills
14、are comparable. BS ISO 6646:2011INTERNATIONAL 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 the yield of husked rice
15、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 equipment. 2 Normative referen
16、ces 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 cereal products Determin
17、ation 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 rice yield amount of mill
18、ed 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 or malformed 4 Principl
19、e 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 6646:2011ISO 6646:2011(E) 2 ISO 2011 All rights reserved5
20、 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 mill, suitable for remova
21、l 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 243331. It is important the labo
22、ratory 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 possible, then reduce it thro
23、ugh 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 should be kept at ambient temper
24、ature 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 husker (5.2) shall be consi
25、dered 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) husk particles in the husked
26、rice. BS ISO 6646:2011ISO 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 husked rice so that the differe
27、nce, 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 length of the test sample ke
28、rnels 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 matter, then spread the paddy an
29、d 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 residual paddy shall be manual
30、ly 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 in accordance with 8.2 to o
31、btain 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 for the time necessary to remo
32、ve 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 bowls. Weigh the head rice a
33、nd 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 apparatus to remove light matter, t
34、hen 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 6646:2011ISO 6646:2011(E) 4 ISO 2011 All rights reserved9 Ex
35、pression 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 fromaParameter Paddy Husked rice Husked rice, y0my/mx1 Milled rice, y1m1/mzm1/mzMilled head rice, y2m2/mzm2/mzaFor variable defi
36、nitions, 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, yhyh= y0 100 % Potential yield of milled rice, ymym= y0y1 100
37、% Potential yield of milled head rice, ymhymh= y0y2 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 precision of the method are summarized for information in An
38、nex 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 using the same method on identical test material in the same la
39、boratory 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) for husked rice, 1 %; b) for milled head rice, 2 %. BS ISO 6
40、646:2011ISO 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 operators using different equipment, will in not more than 5 % of ca
41、ses 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 following information: a) all information necessary for the complete
42、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 regarded as optional, together with details of any incidents which ma
43、y 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 6646:2011ISO 6646:2011(E) 6 ISO 2011 All rights reservedAnnex A (normative) Procedure schemes Laboratory sampleTest sampleTest portion (mx 200 g) m
44、yMixing and reductionMoisture check (Clause 7) Dehusking (testing husker; see 5.2) Husked riceRemoval of light and extraneous matterFigure A.1 Starting from paddy or parboiled paddy: yield of husked rice BS ISO 6646:2011ISO 6646:2011(E) ISO 2011 All rights reserved 7Laboratory sampleTest sampleTest
45、portion (mx 200 g)myAliquot (mz 100 g) m1m2Mixing and reductionMoisture check (Clause 7) Removal of light and extraneous matterHusked riceMilling (testing mill; see 5.3) Milled riceSeparation of head rice from remainderMilled head riceDehusking (testing husker; see 5.2) Figure A.2 Starting from padd
46、y or parboiled paddy: yield of husked rice, milled rice and milled head rice BS ISO 6646:2011ISO 6646:2011(E) 8 ISO 2011 All rights reservedLaboratory sampleTest sampleAliquot (mz 100 g) m1m1Mixing and reductionMoisture check (Clause 7) Removal of light and extraneous matterHusked riceMilling (testi
47、ng mill; see 5.3) Milled riceSeparation of head rice from remainderMilled head rice2Figure A.3 Starting from husked rice or husked parboiled rice: yield of milled rice and milled head rice BS ISO 6646:2011ISO 6646:2011(E) ISO 2011 All rights reserved 9Annex B (informative) Results of an interlaborat
48、ory 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 different types of kernel, gave the statistical results, analysed in accordance with ISO 5725-1:19942and ISO 572
49、5-2:19943, shown in Tables B.1 and B.2. The f value was 10 %. Table B.1 Repeatability and reproducibility of yhRice 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, sr, g/100 g 0,27 0,17 0,19 0,24 0,18 Coefficient of variation of repeatability, % 0,34 0,21 0,24 0,28 0,22 Repeatability limit, r (r = 2,83 sr) 0,75 0,48 0,53 0,67 0,52 Standard deviation of
