Study On Edible Oil Quality Testing Techniques And Instrument Development Based On Dielectric Property

With high temperature heating added, edible oil will incur various changes, such as flavor and aroma etc.While, main causes of the changes said above should be the changing of substances within edible oil, and also these changes has further changed the substance hot property and dielectric property. So, we can structure the content and quality of edible oil with dielectric parameters. Then, through conducting research and study the dielectric property, we can analyze and supervise the content, structure, and status etc qualities.During our test, we selected soybean oil, colza oil, and blend oil as our test samples. Through parallel plate capacitor, we gained the dielectric parameter changes of the said test samples during the whole process of hours' repeated heating. With the parameters, we analyze the correlations between parameter and quality indicator, and finally, we come to the following conclusion: under the circumstances of voltage 1V, current 1mA,and 100Hz～5MHz frequency ranges, we find the best test frequency point will be F=800 kHz. After analyzing correlations among related, the said samples' acid value, peroxide value, iodine value, index of saponification, and color difference have comparatively good correlations with dielectric parameter impedance, capacity, inductance, and susceptance at the point of F=800kHz, so, theoretically speaking,it is practicable to reflect edible oil quality through changes of dielectric properties.We select data from the result of said test, and put them into mathematical modeling software-MATLAB, and establish matrix database for each data we gained. Through MATLAB, we start linear solving task on various oil samples, and finally come up with physical parameter linear equation for three edible oil samples. Then, we can use the mathematical modeling, which reflects the correlation of dielectric parameters and physical & chemical indicators. Finally, this mathematical modeling becomes our theory according. Through error of fitting method, we validated its correctness, and this provided us a strong theoretical base for edible oil quality checking instrument, take soybean oil as an example, the establish equation of the detecting instrument as follows: With AT89S52 single chip (micro controller) as the control system, we design checking instrument with capacity measuring circuit, conversing circuit, and LED circuit etc electronic components. By this instrument, we can measure the acid value, peroxide value, iodine value and index of saponification conveniently. Therefore, we are able to determine quality status of edible oil. Also, instrument quality is assured after examining with tremendous test data. Our instrument has provided a quick and Convenient way to determine the edible oil quality.