Study Of The Non-destructive Measurement Based On The Dielectric Properties Of Edible Fungi During Drying Process

China is a big nation for production and consumption of edible fungi. Water content isa key parameter of controlling quality of products during drying process which is theimportant method of storage. But there is a quite error on account of testing water contentby experience, leading to a great deal deteriorism, rot, and economic loss.of products in thestorage and transportation process. In recent years, the non-destructive measurement byusing physical properties is gradually attached importance to all over the world. There is agreat development for the study on on-line measurement by using the physical principlesof infrared, MRI and microwave. The method by using a HIOKI-3532-50 LCRinstrumenter and self-made plate electrodes to measure the change in dielectric propertiesof six kinds of edible fungi during drying process.The mathematical model with water content and dielectric characteristic parameters ofedible fungi are established, developed the edible fungus A on-line measurement system indrying process is exploited and it give a base in the theory to study of controlling automaticon drying process in the further.Capacitance is the index to evaluate the water content of edible fungi during drying processaccording to the result of change in dielectric property of air. The suitable testingconditions are square planeside for10.0cm length, 2.0cm distance. The capacitance ismeasured at 0.5kHz～50kHz frequency.2. There is a correlations between the weight of the water content and capacitance.The equivalent mathematical models with water content and capacitance for six kinds ofedible fungi by the theory of model founded are showed as following:y=0.9107x~3-13.3410x~2+87.9211x-231.3265; y=11.4282x~2-93.8820x+189.2071;y=11.4282x~2-93.8820x+189.2071; y=14.9397x~2-135.7060x+305.9221;y=13.6341x~2-133.2035x+336.1424; y=98.7126x-515.7411(y is water content, x is equivalent capacitance).According to a set of equivalentmathematical models, the sample water content are simulated at real time and the water content are evaluated during drying process.3. According to the modularization programming and open-loop automation pattern,a automatic-testing system on-line measurement using dielectric properties during dryingprocess of edible fungi was developed.Besides the basic on-line measuring function, thealarm is started up when the water content of object can't reach the aim Consumer can setthe beginning and stopping time by the man-machine conversation operationinterface.The water content and whole movemental tendency are capable of acquiring bythe real time inspection interface of the automatic-testing system.