| In the paper, the white corn tangkang/zhongnuo1 and the soybean zhonghuang37/chengdou39 with different initial moisture content were used as main materials, determinated the rate of adsorption/desorption at 10,20,25,30,35? under RH65%, RH86%, RH100% and the coefficients of hygroscopic expansion in the process of adsorption and desorption and the chang of the glass transition temperature(Tg) of corn grain with the moisture content and the method to detect broken rate of corn with Staining. Analysis summary thses indicators, the theory basis for reasonable ventilation system for reducing moisture and scientific storage were provided of corn and soybean of our country, the results showed that:(1) The rate of adsorption/desorption of corn and soybean was influenced by environmental temperature/humidity and initial moisture content(IMC) of grain. The rate of adsorption of corn grain(IMC, 5.89%~11.53%) and soybean grain(IMC, 4.33%~12.66%) was increased as the temperature/humidity increased at 10,20,30? under RH65%, RH86%, RH100%. The rate of desorption of corn grain(IMC, 20.20%~21.34%) and soybean grain(IMC, 17.58%~17.89%) was increased as the temperature increased and the humidity decreased at 10,20,30? under RH65%, RH86%, RH100%. The initial rate of adsorption of corn grain and soybean grain was decreased as the IMC increased and the initial rate of desorption of corn grain and soybean grain was increased as the IMC increased at the same temperature(10?,20?,30?) under the same humidity(RH65%, RH86%, RH100%).(2) The moisture diffusion coefficient of normal/high IMC corn grain(IMC, 10.18%~21.34%) and soybean grain(IMC, 11.74%~17.89%) was decreased as the humidity(RH65%, RH86%, RH100%) increased in the process of adsorption/desorption. The moisture diffusion coefficient of low IMC corn grain(IMC, 5.89%~6.24%) and soybean grain(IMC, 4.33%~5.86%) was increased as the humidity(RH65%, RH86%, RH100%) increased in the process of adsorption.(3) Compared with 10?, the moisture ratio(MR) of higher temperature(20~35?) sample grain fell to a constant quickly as the extension of adsorption and desorption time in the same humidity(RH65%, RH86%, RH100%).That is the initial adsorption/ desorption sate of sample grain was increased to a constant quickly as the temperature increased in the same humidity. The moisture ratio of the normal/high IMC sample grain had moer time to a constant as the humidity(RH65%,RH86%, RH100%) increased in the same temperature(10~35?). That is the rate of moisture adsorption needed more time to a constant.(4) For the corn grain with normal IMC(10.18%~11.53%), its moisture adsorption rate at 20 to 35? quickly deceased within 91 to 115 h, thereafter changed gently, and slowly deceased within 139 h at 10? in the range of RH 65% to 100%. For the soybean grain with normal IMC(11.74%~12.66%), its moisture adsorption rate at 20 to 35? quickly deceased within 103 to 127 h, thereafter changed gently, and slowly deceased within 139 h at 10? in the range of RH 65% to 100%.(5) In a certain moisture content of drying base within the scope of 5.17% to 47.20% for corn and 4.17% to 50.11% for soybean, the corn and soybean grain volume was increased as moisture adsorption; then the grain volume was decreased as moisture desorption. Overall, the coefficients of hygroscopic expansion of corn and soybean grain in the process of adsorption was higher than the desorption process. The coefficients of linear hygroscopic expansion of length and width were higher than thickness in the process of adsorption and desorption.(6) By DSC experiments show that the glass transition phenomenon happens in corn grain in the process of heating. The glass transition temperature with the increasing of moisture content of corn grain, showed a trend of power function decline. And the less difference between maize varieties.(7) Fast green(FCF) staining method was suitable for the detection of corn broken rate and be able to complete the test in an hour. It was concluded that, this protocol in line with the requirements of rapid detection. And this method was not suitable for soybean crushing rate of detection. Whether the staining was applicable to other grain is remain to studied. |
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