Study On Mechanism And Application Of Phtometric Sensors For Reducing Sugar Based On Complementary Color

Nowdays, analysis methods used in fermentation and food processing are old in our country, and that automatic control level is relatively low, only existing some usual control means such as temperature, dissolved oxygen and pH. As main carbon sources and energy, carbohydrates are important control parameters, whose changes of concentration directly affect the quality, overall yield and production costs of fermentation product and food. Because of lacks of analysis sensor for carbohydrates in food and fermentation industries in our country, we have developmented photometric sensor of reducing sugar based on complementary color in this study.According to basic principle of photoelectric technology, complementary color mechanism, and the characteristic of color changes of test samples with Fehling's reagents during thermometric titration, and forthermore color condition when titration end point, we choose appropriate complementary color source to improve signal change rate of light transmittance on the basis of the former titration device of reducing sugar. We greatly emphasize anti-interference abilities of the system by choosing appropriate elements and optimizing relevant electrocircuit. Some difficult problems such as turbidity from ample culture medium and bacterial cells, color from fermentation liquid and bubbles from thermal titration are solved. Moreover, reducing sugar of fermentation can be determinated rapidly and accurately. So we offer new technology for analysis and control of fermentation.This sensor utilizes light-emitting diode complementary to color of reaction liquid as monochromatic light source. Selenium photocell is used photoelectric converter to design power, electrocircuit, control program and tiny thermal titration device of the sensor including temperature, heating, mixing and solution transfering and so on. All kinds of situation and step are controled by the computer, thus error is much less than random error. The measuring time for each sample is 3 minites; and linear range is 0-1.0%(r=0.9998); the RSD is 0.74%(n=10); and the recovery is 99.2 %.Photometric sensor of reducing sugar based on complementary color is used to measure glutamic acid fermenting liquid. The results show this sensor has strong anti-interfere capacity. Samples can be determinated directedly without filtering or decoloring treatment with recovery 98.6-101.5 %. Testing cost is relative low and consumption of reagents are smaller than general titration methods. The content changes of reducing sugar and glucose during the process of glutamic acid fermentation were determinated. The results show that reducing sugar is important biochemical indexes during the process of fermentation control.Reducing sugar in potato was measured by photometric sensor based on complementary color. The comparison experiment shows this kind of sensor can quickly and accurately test samples. So this photometric sensor is very significant to products quality, security of the deep-processing of potato, which also important to the study of potato breeding.