ISO 11746:2020 pdf free.Rice一Determination of biometric characteristics of kernels.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 7301, ISO 24333 and the following apply.
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3.1 biometric characteristics length, width and thickness of the kernel measured along the three Cartesian axes Note 1 to entry: See Figure A.1.
4 Principle
Manual selection of kernels and measurement of their biometric characteristics with a micrometer.
5 Apparatus
Usual laboratory apparatus and, in particular, the following.
5.1 Sample divider, conical sampler or multiple-slot sampler with a distribution system.
NOTE Some sample dividers are described in ISO 24333.
5.2 Tray, or equivalent device, coloured in contrast with the colour of the rice to be evaluated.
5.3 Tweezers, of different types (metal, plastic, round tips or pointed, etc.), for easy handling of
kernels.
5.4 Micrometer, or equivalent device capable of being read to the nearest 0,01 mm and which ensures that no kernel deformation occurs during measurement. Avoidance of kernel deformation is particularly important for husked rice.
6 Sampling
Sampling is not part of the method specified in this document. A recommended sampling method is
given in ISO 24333. It is important the laboratory receives a truly representative sample that has not been damaged or changed during transport or storage.
7 Procedure
7.1 Preparation of the test sample
Mix and reduce an aggregate sample, using a sample divider (5.1). Repeat the first step of dividing at
least three times. By the following steps, reduce the sample until a test sample of about 50 g is obtained. Spread it on the tray (5.2) and, with the aid of tweezers 5.3), remove extraneous matter, immature and/or malformed kernels, and kernels in any way broken to obtain the test sample.
8.3 Expression of results
Report the mean values of the length, width, thickness and length/width ration of the kernels to the
nearest 0,01 mm.
9 Precision
9.1 Interlaboratory test
Details of an interlaboratory test on the precision of the method are summarized in Annex B. It is
possible that the values derived from this interlaboratory test are not applicable to other types of rice
and mixtures of other varieties.
9.2 Repeatability
The absolute difference between two independent single test results, obtained using 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 repeatability limits:
r1= 0,125 mm
rb = 0,049 mm
rσ= 0,040 mm
for kernel length, width and thickness, respectively. The test report shall contain at least the following information: a] all information necessary for the complete identification of the sample; the sampling method used, if known; c) the test method used, with reference to this document, i.e. ISO 11746; d) all operating details not specified in this document, or regarded as optional, together with details of any incidents that 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; g) the date of the test.ISO 11746 pdf download.