BS ISO 771:2021 pdf download – Oilseed meals — Determination of moisture and volatile matter content
This document specifies a method for the determination of the moisture and volatile matter content of oilseed meals obtained by the extraction of oil from oilseeds by pressure and/or solvent.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 5502, Oilseed residues — Preparation of test samples
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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moisture and volatile matter content
loss in weight measured under the operating conditions specified in this document
Note 1 to entry: The moisture and volatile matter content is expressed as a mass fraction in grams per 100 g.
The sample is ground to a particle size of 1 mm, followed by drying of a test portion at (103 ± 2) °C in an oven at atmospheric pressure, until practically constant mass is reached.
5.1 Analytical balance, readability 0,000 1 g, weighing precision 0,001 g.
5.2 Mechanical mill, easy to clean and allowing the meals to be ground, without heating and without appreciable change in the moisture, volatile matter and oil content, to particles passing completely through the sieve (5.3).
5.3 Sieve, with apertures of diameter 1 mm.
5.4 Flat-bottomed vessel, of metal, resistant to attack under the test conditions, provided with a well fitting lid and allowing the test portion to be spread to about 0,2 g/cm 2 (e.g. diameter of vessel 50 mm to 70 mm, height about 30 mm). Glass vessels with ground closures may also be used.
8 Expression of results — Method of calculation and formula
The moisture and volatile matter content w, as a mass fraction in grams per 100 g, is given by Formula (1):
m 0 is the mass, in grams, of the vessel;
m 1 is the mass, in grams, of the vessel and test portion before drying;
m 2 is the mass, in grams, of the vessel and test portion after drying.
Use the mean value from the 2 reps if repeatability conditions are satisfied (9.2) and express the result to one decimal place.
9.1 Results of interlaboratory test
Details of an interlaboratory test on the precision of the method are summarized in Annex A. The values derived from this interlaboratory test might not be applicable to concentration ranges and matrices other than those given.
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 r given as followed:
— for mean value less than 4,0 % (in mass fraction): r = 0,2 %;
— for mean value more than 4,0 % (in mass fraction): r = 0,018x + 0,13 (see Figure A.1).
With x corresponding to the mean value of two reps. Some examples of r values are given in Annex B.
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 R given as followed:
— for mean value less than 4,0 % (in mass fraction): R = 0,4 %;
— for mean value more than 4,0 % (in mass fraction): R = 0,033x + 0,27 (see Figure A.1).
With x corresponding to the mean value of two reps. Some examples of R values are given in Annex B.
10 Test report
The test report shall specify:
a) all information necessary for the complete identification of the sample;
b) the test method used with reference to this document, i.e. ISO 771:2021;