ISO 11746:2020 Rice — Determination of biometric characteristics of kernels..
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.
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.
7.1 Preparation of the test sample
Mix and reduce an aggregate sample, using a sample divider (511). 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.
7.2.1 Randomly draw out two sets of 100 kernels from the test sample obtained in LI.
7.2.2 While maintaining each kernel motionless in the correct orientation (see Annex A) with the aid of tweezers (5), measure the biometric characteristics of the kernels of both sets (see L2J) using the micrometer (Sd). Report the values to the nearest 0,01 mm.
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 cases, be greater than the reproducibility limits:
R l = 0,337 mm
R b = 0,163 mm
R δ = 0,092 mm
for kernel length, width and thickness, respectively.
10 Test report
The test report shall contain at least the following 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 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.