ISO 16624-2020 pdf free.Wheat flour and durum wheat semolina — Determination of colourby diffuse reflectance colorimetry.
This document specifies a method for the determination of colour in durum wheat semolina and wheatflour by diffuse reflectance colorimetry.
lt is applicable to industrial semolina and flour.The method can be applicable to flour obtained from experimental mill.
There are no normative references in this document.
colour metric space:expression of the colour of an object or of a light source by some parameters expressed by figures.
illuminant:light source characterized by a spectral curve, where the energy relative distribution is defined in thefield of wavelengths that are able to influence the object colour vision.
The principle is based on the measurement of colour directly on semolina and flour by a reflectancecolorimeter.
The colour of wheat milling product (semolina and flour) is due to the pigments naturally present inwheat grains. These pigments (xanthophyl’s and carotenoids) are responsible for the colour visuallyperceived in milling products.
Reflectance colorimeter1) with head of measurement suitable for carrying out measurements ofabsolute chromaticity.Consists of a setting system and a cell samples-driver.The colorimeter shall be characterized by the following technical characteristics:
system of measurement with pulsed xenon lamp diffused to the light and receipt of the radiationreflected to 0° (geometry d/0°);
circular surface of measurement;
measurements of chromaticity expressed as L*, a*,b*(see CIE 1976) with the use of the illuminantCIE D65 (illuminant D6;: representing one of the relative spectral distribution of the day-light energythat corresponds to a proximal colour temperature similar to 6 504 K);
time of measurement 1 s;possibility of calibration with reference plate;repeatability within a DE*0,6(30 measurements effected to an interval of 10s on the reference plate)5.2 Accessory samples-driver and cell for the measurement of granular materials.
The dimensions of the cell that defines the quantity of sample submitted to the test are: externaldiameter = 60 mm, diameter inside hole = 22 mm, thickness = 9 mm.ISO 16624 pdf download.