2016/6/181 ISO 6540 ISO 6540 (first edition 1980) International Standard Maize – Determination of moisture content (on milled grains and on whole grains

2016/6/182 ISO 6540 Contents 1. Reference method 1. Reference method 1-1. Application 1-1. Application Definition 1-3. Apparatus 1-3. Apparatus 1-4. Preparation of the test s 1-4. Preparation of the test sample Procedure Calculation and expression of results Test report 2. Routine method on whole grains 2-1. Application 2-1. Application 2-2. Apparatus 2-2. Apparatus Procedure Calculation and expression of results 2-5. Test report

2016/6/ Application 1-1.Application This method is applied to maize. The basic method is ISO712 (for cereal grains), with a number of amendments. Two methods :one is on milled grains, the other is on whole grains ISO Reference method

2016/6/ Definition Loss in mass, expressed as a percentage, undergone by the product under the conditions specified in this International standard Loss in mass, expressed as a percentage, undergone by the product under the conditions specified in this International standard ISO Reference method

2016/6/ Apparatus 1-3. Apparatus 1) Analytical balance 2) Grinding mill 2) Grinding mill 3) Metal dish 4) Oven 4) Oven 5) Desiccator ISO Reference method

2016/6/186 ISO 6540 Reference method 1-3. Apparatus-1 1) Analytical balance Capable of weighing to an accuracy of ±1mg Capable of weighing to an accuracy of ±1mg

2016/6/ Apparatus Apparatus-2 2) Grinding mill not absorb moisture, easy to clean, not absorb moisture, easy to clean, without heat, tightness to air, without heat, tightness to air, particles of the dimensions in Table 1. particles of the dimensions in Table 1. ISO Reference method

2016/6/ Apparatus-2-Table Apparatus-2-Table 1 Table 1 ― Particle size distribution of products not requiring grinding Particle size (mm) Proportion (%) ≦ 1.7 （ 1.8 ） a 100 ＞ 1.0 （ 1.0 ） b <10 ＜ 0.5 （ 0.56 ） a >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 ISO Reference method

2016/6/ Apparatus Apparatus-3 3) Metal dish Non-corrodible, Non-corrodible, tight-fitting, an tight-fitting, an effective surface area effective surface area (not more than 0.3g/cm (not more than 0.3g/cm 2 ) ISO Reference method

2016/6/1810 ISO 6540 Reference method 1-3. Apparatus-4 4) Oven ・ Constant and stable at 60 ～ 80 ℃,130 ～ 133 ℃ ・ Regain time in less than 30min ・ Effective ventilation

2016/6/ Apparatus Apparatus-5 5) Desiccator Containing an effective desiccant Containing an effective desiccant ISO Reference method

2016/6/ Preparation of the test s 1-4. Preparation of the test sample-1 characteristics specified in Table 1, it does not need to be characteristics specified in Table 1, it does not need to be ground. ground. If the sample does not have the particle size If the sample does not have the particle size either without pre-conditioning or with pre-conditioning either without pre-conditioning or with pre-conditioning 1) Grinding products without pre-conditioning when its 1) Grinding products without pre-conditioning when its moisture content is between 9% and 15% moisture content is between 9% and 15% 2) Products shall be pre-conditioned so as to bring their 2) Products shall be pre-conditioned so as to bring their moisture content to between 9% and 15% before grinding moisture content to between 9% and 15% before grinding ISO Reference method

2016/6/ Preparation of the test s 1-4. Preparation of the test sample-2 sample most ９％～ 15 ％ large particle size grinding NO YES NO preparation sample pre- conditioning ISO Reference method

2016/6/ Preparation of the test s 1-4. Preparation of the test sample-3 If the moisture content is more than 15%, If the moisture content is more than 15%, 1) weigh, to 10mg, provide the test sample about 100g on the metal boat without lid 1) weigh, to 10mg, provide the test sample about 100g on the metal boat without lid 2) place in the oven at 60 ℃～ 80 ℃ for a pre-drying operation 2) place in the oven at 60 ℃～ 80 ℃ for a pre-drying operation 3) the cooling of pre-drying sample to laboratory temperature, 3) the cooling of pre-drying sample to laboratory temperature, for at least 2h. for at least 2h. 4) after weighing the sample, grind about 30g of this product 4) after weighing the sample, grind about 30g of this product If the moisture carry out a pre- wetting operation in suitable atmosphere until a moisture content within the limits. If the moisture content is less than 9%, carry out a pre- wetting operation in suitable atmosphere until a moisture content within the limits. ISO Reference method

2016/6/ Procedure 1) Number of determination Carry out two determinations on test portions taken from different test samples. Carry out two determinations on test portions taken from different test samples. 2) Test portion Rapidly weigh, to the nearest 1mg, a quantity of 8g ±1g of the laboratory sample in the dishes. Rapidly weigh, to the nearest 1mg, a quantity of 8g ±1g of the laboratory sample in the dishes. 3) Drying Do not open the oven door during drying. Do not open the oven door during drying. Place the open dish containing the test portion together with the Place the open dish containing the test portion together with the lid, in the oven and leave for 4hours from the moment when the oven temperature is again 130 ﾟ C±3 ﾟ C. lid, in the oven and leave for 4hours 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 1mg. When the dish has cooled to laboratory temperature, weigh it to the nearest 1mg. ISO Reference method

2016/6/1816 Diagram of Procedures for products to be ground ISO Reference method Without conditioning

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

2016/6/ Calculation and expression of results 1-6. Calculation and expression of results The moisture content, m H20, expressed as percentage by mass of products as received, is given by the following equations. The moisture content, m H20, expressed as percentage by mass of products as received, is given by the following equations. 1) Without pre-conditioning 1) Without pre-conditioning m =(1 – w 1 /w 0 )×100% m H20 =(1 – w 1 /w 0 )×100% where w 0 and w 1 are the weights, in grams, of the test where w 0 and w 1 are the weights, in grams, of the test portion and the dried test portion, respectively. portion and the dried test portion, respectively. 2) With pre-conditioning 2) With pre-conditioning m H20 ={1 – ( w 1 w 3 )/(w 0 w 2 )}×100% m H20 ={1 – ( w 1 w 3 )/(w 0 w 2 )}×100% where w 2 and w 3 are the weights of before and after pre- where w 2 and w 3 are the weights of before and after pre- conditioned, respectively. conditioned, respectively. The result is the arithmetic mean of two single determinations which meet the repeatability requirement, shall not exceed 0.15g of moisture per 100g of sample.Round the result to two places of decimals. The result is the arithmetic mean of two single determinations which meet the repeatability requirement, shall not exceed 0.15g of moisture per 100g of sample.Round the result to two places of decimals. ISO Reference method

2016/6/ Test Report 1-7. Test Report Information Information 1) Sample identification 1) Sample identification 2) sampling method 2) sampling method 3) reference to International Standard 3) reference to International Standard 4) test results 4) test results 5) repeatability 5) repeatability 6) operating details, influenced the test results 6) operating details, influenced the test results ISO Reference method

2016/6/ Application 2-1.Application This method is applied to maize in whole. Not use for experts’ reports, or for calibration or checking of moisture meters ISO Routine method on whole grains

2016/6/ Apparatus 2-2. Apparatus 1) Analytical balance 2) Metal dish 2) Metal dish 3) Oven 4) Desiccator 4) Desiccator ISO Routine method on whole grains

2016/6/ Apparatus Apparatus-1 1) Analytical balance Capable of weighing to an accuracy of ±10mg Capable of weighing to an accuracy of ±10mg ISO Routine method on whole grains

2016/6/ Apparatus Apparatus-2 2) Metal dish Non-corrodible, Non-corrodible, tight-fitting lid, a diameter of 50 ～ 60 mm and height of 25 mm tight-fitting lid, a diameter of 50 ～ 60 mm and height of 25 mm ISO Routine method on whole grains

2016/6/ Apparatus Apparatus-3 3) Oven ・ Constant and stable for 38h at 130 ～ 133 ゜ C ・ Regain time in less than 30min ・ Effective ventilation ISO Routine method on whole grains

2016/6/ Apparatus Apparatus-4 4) Desiccator Containing an effective desiccant Containing an effective desiccant ISO Routine method on whole grains

2016/6/ Procedure 1) Number of determination More than two determinations are required when the absolute More than two determinations are required when the absolute difference between the two results is less 0.15% moisture content. difference between the two results is less 0.15% moisture content. 2) Test portion Rapidly weigh, to the nearest 10mg, a quantity of 20g ～ 40g of the laboratory sample in the dishes. Rapidly weigh, to the nearest 10mg, a quantity of 20g ～ 40g of the laboratory sample in the dishes. 3) Drying Do not open the oven door during drying. Do not open the oven door during drying. Place the open dish containing the test portion together with the Place the open dish containing the test portion together with the lid, in the oven and leave for 38±2hours from the moment when the oven temperature is again 130 ﾟ C±3 ﾟ C. lid, in the oven and leave for 38±2hours 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 10mg. When the dish has cooled to laboratory temperature, weigh it to the nearest 10mg. ISO Routine method on whole grains

2016/6/ Calculation and expression of results 2-4. Calculation and expression of results The moisture content, m H20, expressed as percentage by mass of products as received, is given by the following equations. The moisture content, m H20, expressed as percentage by mass of products as received, is given by the following equations. m =(w 1 -w 2 )×100/(w 1 -w 0 )% m H20 =(w 1 -w 2 )×100/(w 1 -w 0 )% where w 1 and w 2 are the weights, in grams, of the test where w 1 and w 2 are the weights, in grams, of the test portion and the dried test portion, respectively. portion and the dried test portion, respectively. w 0 : the empty dish and its lid 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. 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. ISO Routine method on whole grains

2016/6/ Test Report 2-5. Test Report Information Information 1) Sample identification 1) Sample identification 2) sampling method 2) sampling method 3) reference to International Standard 3) reference to International Standard 4) test results 4) test results 5) repeatability 5) repeatability 6) operating details, influenced the test results 6) operating details, influenced the test results ISO Routine method on whole grains