International Standard ISO 6540 first edition 1980 Maize

International Standard ISO 6540 (first edition 1980) Maize – Determination of moisture content (on milled grains and on whole grains 2020/10/7 1

ISO 6540 Contents n n n n 1. Reference method 1 -1. Application 1 -2. Definition 1 -3. Apparatus 1 -4. Preparation of the test sample s 1 -5. Procedure 1 -6. Calculation and expression of results 1 -7. Test report 2. Routine method on whole grains 2 -1. Application 2 -2. Apparatus 2 -3. Procedure 2 -4. Calculation and expression of results 2 -5. Test report 2020/10/7 2

ISO 6540 1. Reference method 1 -1. Application n This method is applied to maize. The basic method is ISO 712 (for cereal grains), with a number of amendments. Two methods : one is on milled grains, the other is on whole grains 2020/10/7 3

ISO 6540 1. Reference method 1 -2. Definition n Loss in mass, expressed as a percentage, undergone by the product under the conditions specified in this International standard 2020/10/7 4

ISO 6540 1. Reference method 1 -3. Apparatus 1) Analytical balance 2) Grinding mill　 3) Metal dish 4) Oven　　　 5) Desiccator 　　　　 2020/10/7 5

ISO 6540 Reference method 1 -3. Apparatus-1 1) Analytical balance 　　Capable of weighing to an accuracy of ± 1 mg 2020/10/7 6

ISO 6540 1. Reference method 1 -3. Apparatus-2 2) Grinding mill 　　　　not absorb moisture, easy to clean, without heat, tightness to air, particles of the dimensions in Table 1. 2020/10/7 7

ISO 6540 1. Reference method 1 -3. Apparatus-2 -Table 1 1　― Particle size distribution of products not requiring grinding Particle　size (mm) Proportion　 (%) ≦ 1. 7（1. 8）a 100 Table ＞ 1. 0（1. 0）b ＜ 0. 5（0. 56）a <10 >50 a Sieve through which this particle size passes. b Sieve through which this particle size does not pass. Products having the particle size distribution given in Table 1 do not need to be ground before the determination 2020/10/7 8

ISO 6540 1. Reference method 1 -3. Apparatus-3 3) Metal dish 　Non-corrodible, tight-fitting, an effective surface area (not more than 0. 3 g/cm 2) 2020/10/7 9

ISO 6540 Reference method 1 -3. Apparatus-4 4) Oven ・Constant and stable at 60～ 80℃, 130～ 133 ℃ ・Regain time in less than 30 min ・Effective ventilation 2020/10/7 10

ISO 6540 1. Reference method 1 -3. Apparatus-5 5) Desiccator 　 Containing an effective desiccant 2020/10/7 11

ISO 6540 1. Reference method 1 -4. Preparation of the test sample-1 s characteristics specified in Table 1, it does not need to be ground. 　　 If the sample does not have the particle size either without pre-conditioning or with pre-conditioning 1) Grinding products without pre-conditioning when its moisture content is between 9% and 15% 2) Products shall be pre-conditioned so as to bring their moisture content to between 9% and 15% before grinding 2020/10/7 12

ISO 6540 1. Reference method 1 -4. Preparation of the test sample-2 s sample NO large particle size YES preconditioning NO most９％～ 15％ YES grinding preparation sample 2020/10/7 13

ISO 6540 1. Reference method 1 -4. Preparation of the test sample-3 s n n If the moisture content is more than 15%, 1) weigh, to 10 mg, provide the test sample about 100 g on the metal boat without lid 2) place in the oven at 60℃～ 80℃ for a pre-drying operation 3) the cooling of pre-drying sample to laboratory temperature, for at least 2 h. 4) after weighing the sample, grind about 30 g of this product If the moisture content is less than 9%, carry out a prewetting operation in suitable atmosphere until a moisture content within the limits. 2020/10/7 14

ISO 6540 1. Reference method 1 -5. Procedure Number of determination Carry out two determinations on test portions taken from different test samples. 2) Test portion Rapidly weigh, to the nearest 1 mg, a quantity of 8 g ± 1 g of the laboratory sample in the dishes. 3) Drying Do not open the oven door during drying. Place the open dish containing the test portion together with the lid, in the oven and leave for 4 hours from the moment when the oven temperature is again 130ﾟC± 3ﾟC. 4) Weighing When the dish has cooled to laboratory temperature, weigh it to the nearest 1 mg. 1) 2020/10/7 15

ISO 6540 1. Reference method Diagram of Procedures for products to be ground Without conditioning 2020/10/7 16

With conditioning 80℃　pre-drying cool down to room temperature take 30 g sample drying 8 g

ISO 6540 1. Reference method n n 1 -6. Calculation and expression of results The moisture content, m. H 20, expressed as percentage by mass of products as received, is given by the following equations. 1) Without pre-conditioning m. H 20 =(1 – w 1/w 0)× 100% where w 0 and w 1 are the weights, in grams, of the test portion and the dried test portion, respectively. 2) With pre-conditioning m. H 20 ={1 – ( w 1 w 3)/(w 0 w 2)}× 100% where w 2 and w 3 are the weights of before and after preconditioned, respectively. The result is the arithmetic mean of two single determinations which meet the repeatability requirement, shall not exceed 0. 15 g of moisture per 100 g of sample. Round the result to two places of decimals. 2020/10/7 18

ISO 6540 1. Reference method 1 -7. Test Report n n n n Information 1) Sample identification 2) sampling method 3) reference to International Standard 4) test results 5) repeatability 6) operating details, influenced the test results 2020/10/7 19

ISO 6540 2. Routine method on whole grains 2 -1. Application n n This method is applied to maize in whole. Not use for experts’ reports, or for calibration or checking of moisture meters 2020/10/7 20

ISO 6540 2. Routine method on whole grains 2 -2. Apparatus 1) Analytical balance 2) Metal dish 　 3) Oven 4) Desiccator 　　　　 2020/10/7 21

ISO 6540 2. Routine method on whole grains 2 -2. Apparatus-1 1) Analytical balance 　　Capable of weighing to an accuracy of ± 10 mg 2020/10/7 22

ISO 6540 2. Routine method on whole grains 2 -2. Apparatus-2 2) Metal dish 　Non-corrodible, tight-fitting lid, a diameter of 50～ 60 mm and height of 25 mm 2020/10/7 23

ISO 6540 2. Routine method on whole grains 2 -2. Apparatus-3 3) Oven ・Constant and stable for 38 h at 130～ 133゜C ・Regain time in less than 30 min ・Effective ventilation 2020/10/7 24

ISO 6540 2. Routine method on whole grains 2 -2. Apparatus-4 4) Desiccator 　 Containing an effective desiccant 2020/10/7 25

ISO 6540 2. Routine method on whole grains 2 -3. Procedure 1) Number of determination More than two determinations are required when the absolute difference between the two results is less 0. 15% moisture content. 2) Test portion Rapidly weigh, to the nearest 10 mg, a quantity of 20 g ～ 40 g of the laboratory sample in the dishes. 3) Drying Do not open the oven door during drying. Place the open dish containing the test portion together with the lid, in the oven and leave for 38± 2 hours from the moment when the oven temperature is again 130ﾟC± 3ﾟC. 4) Weighing When the dish has cooled to laboratory temperature, weigh it to the nearest 10 mg. 2020/10/7 26

ISO 6540 2. Routine method on whole grains 2 -4. Calculation and expression of results n n The moisture content, m. H 20, expressed as percentage by mass of products as received, is given by the following equations. m. H 20 =(w 1 -w 2)× 100/(w 1 -w 0)% where w 1 and w 2 are the weights, in grams, of the test portion and the dried test portion, respectively. w 0 : the empty dish and its lid The result is the arithmetic mean of two single determinations which meet the repeatability requirement(0. 2%). Round the result to one places of decimals. 2020/10/7 27

ISO 6540 2. Routine method on whole grains 2 -5. Test Report n n n n Information 1) Sample identification 2) sampling method 3) reference to International Standard 4) test results 5) repeatability 6) operating details, influenced the test results 2020/10/7 28