Comparison And Analysis Of Grain Moisture Determination Methods

In order to study the grain moisture determination methods, this paper selected the wheat, corn and brown rice as experiment materials, and studied the main influence factors in the process of determination, difference between the national standard method for the determination of grain moisture content, improvement of the moisture measurement method of high moisture grain, correlation of the rapid grain moisture measuring instruments respectively, and the relevance was to determine the grain moisture content accurately and rapidly. The main conclusions were summarized as follows:(1) The position of samples in the oven, granularity of samples, the crushing equipment, specifications of drying box and environmental temperature were influenced on the determination results in a certain degree. It was through experiments concluded that the most accurate of measurement is electric blast oven, the moisture value of the Chopin grinding mill is higher than the Cyclone mill and the Grains electric grinder, and its moisture is minimized of loss.The influence of specifications of drying box and environmental temperature on grain moisture detection was small, and it did not cause significant changes in the moisture level when the sample size is 2.0mm.(2) For wheat and brown rice, GB105 ℃constant weight method and the timing and temperature drying method were the conventional methods for the determination of domestic grain moisture, but the moisture content of values determined by the ISO conventional method are higher than the measurements of the standard method. The result measured by GB105℃constant weight method had a good correlation with the method of timing and temperature, and there was a stable difference. The moisture content of the whole grain of corn drying was the most accurate. In terms of efficiency and accuracy, this paper suggested that the timing and temperature method is adopted.(3)The critical value which determined by testing three kinds of high moisture using the method of drying in twice time was 16%. The moisture content of the sample whose first drying time controlled in 1h were less than 23% of wheat and brown rice, below 24% of the corn, when the corresponding grain moisture content was greater than the corresponding water point, the first time would be controlled in 1.5 h. For the high moisture corn, the result was perfect when 30 g of corn grain were drying in one time, the continuous drying time for the different identified moisture of the corn were 2 h.(4)The results of using LDS-1H computer moisture measuring instrument for detection the moisture of wheat and rice were accurate, and the result of water detection of maize was 0.1% bigger than the real. The Infraneo near infrared grain analyzer instrument was applied to detect the moisture content of the sample, smaller the size of sample grinding particle is, the result was more close to the actual moisture content. The best condition of microwave heating method for determination of moisture content for grain was that microwave power was 350 W for wheat and brown rice, 560 W for corn, the drying time was 8 min, and sample quantity was 2 g.