大豆の高品質乾燥調製に関する研究

The production of soybeans increases every year owing to the increase of demand for the domestic soybeans among the consumers in Japan and the rate of use of combine for harvesting soybeans increases because of a labor saving harvesting method. But, drying processing technique for the high moisture content soybeans harvested by combine has been retarded, and the degradation of soybeans and the heavy labor work in the process of drying become a problem. The efficient drying processing technique keeping the quality of soybeans harvested by combine, has been strongly required. In the drying processing of high moisture content soybeans, there occurs the risk of swelling in soybeans when the air ventilation in the layers is not sufficient. The activity of microorganism or mold increases when the temperature of the air exceeds 80% humidity and over 20℃temperature. It is necessary to adjust the temperature and humidity of the air ventilation to be out of this dangerous zone. In the meantime, it is necessary also to control the drying rate of soybeans so as to avoid the occurrence of the seed-coat cracking or the wrinkle of soybeans. To develop the effective artificial drying method keeping the quality of soybeans, the investigation on the physical properties of soybeans relating to the drying processing and the analysis of the drying process of soybeans are indispensable. However, the study has been retarded in comparison with the study of rice or wheat. In this study, the fundamental properties of soybeans relating to the drying and the characteristics of the pressure loss in driers such as flat be driers equipped with the bucket conveyer or dry stores were clarified and a drying simulation model for analyzing the process of drying was developed and investigated and the mechanism of the generation of coat cracking of soybeans and the effective treatment of the ventilation air to minimize the coat cracking were cleared. Through this study, the fundamental techniques for drying soybeans harvested by combine were developed. In the first chapter, the significance and objectives of this study were described based on an outline of soybean production and studies on soybean drying... In the second chapter, the dependence of physical properties as specific volume, bulk volume, rate of volume on moisture content of soybeans (tachinagaha, tamahomare, fukuyutaka, suzuyutaka, enrei variety) was theoretically considered and determined as follows with principal properties of specific volume of drymatter V,_0, coefficient of rate of volume k of average soybeans. V_m=V_0+γ・m=0.771+0.965m (0.1<m), V_m=(m_2+2V_<0c>m+V_0^2)_<1/2>(0<m) V_m^1=Vm/(1-ε)=6V_m/kπ, k=1.00-0.029m values i.e m ; moisture content (d.b.decimal), V_m ; specific volume based on dry material(10^<-3>m^3/kg), V_m^1 ; specific bulk volume, 1-ε ; rate of kernel volume, V_0=0.771(10^<-3>m^3/kg), V_<0c>=0.7460 Hence, physical properties of soybean for a drying simulation model were shown with principal parameters of V_0, V_<0c>, k. In the third chapter, the pressure loss of soybeans was examined and the data was analyzed using the non-dimensioned Navier-Stokes equations for forced air in accumulations. And resistance factors or friction factors of soybeans were expressed as the function of Reynolds number, to esteem a pressure loss in air forced layers of soybeans by calculation. We could get an experimental equation of resistance factor that was applied for generally to pressure loss of soybeans, in 40<Re<200 ranges which is used with usual forced air drying. We could express characteristics of pressure loss of soybeans, as the function of space rate, ratio of surface area and velocity of air by using an experimental equations of the resistance factor or a friction factor. The characteristics of pressure loss of soybeans were able to be approximated with high accuracy. In the forth chapter accuracy of a simulation model for drying soybeans that takes into account moisture transport in gas and solid phases under an inconstant condition of air flow was investigated. It was found that temperature, humidity of air passing through a deep bed of soybeans and the moisture contents of accumulation layers of soybeans using different soybeans and two different types of experimental dryer were able to be estimated correctly by using values of the fundamental drying properties such as density, specific surface area, space ratio, equilibrium moisture content of soybeans, and specific heat, and mass transfer coefficients of soybeans. In the fifth chapter, seed-coat cracking of soybeans occurs easily during the process of air drying.In order to determine the relationship between external air temperature/humidity and distortions in seed-coat cracked grains, the rates of seed-coat cracking of soybeans subjected to mono-layer drying were investigated under various air drying conditions of different temperature and humidity combinations, and the critical distortions were estimated. Based on the results, the required temperature and humidity conditions of air passing through deep bed of soybeans for minimizing coat cracking and preventing swelling due to high air temperature were clarified.

書誌情報

中央農業総合研究センター研究報告
en : Bulletin of the National Agricultural Research Center

巻 3, p. 1-49, 発行日 2003-03-01

出版者

独立行政法人農業技術研究機構中央農業総合研究センター

ISSN

収録物識別子タイプ

ISSN

収録物識別子

1881-6738

DOI

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2023-05-15 15:37:47.184478

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