Monitoring the process of yogurt spoilage by dielectric measurements and spread plate method

In my research work, I primarily focused on the investigation of yogurt (made from home-made raw milk) spoilage by microbiological and dielectric measurements. During the experiment, I continuously monitored the changes in aerobic and anaerobic Lactobacillus cell counts of the product, as a possible spoilage process would cause the deteriorative microbes to displace the lactic acid bacteria, and I also monitored the changes in the dielectric properties of the sample material at 400 MHz frequency. The research results verified that there is a strong correlation between the variation in live cell counts and dielectric parameters in both aerobically and anaerobically cultured lactic acid bacteria. The main conclusions of the results are that the change in the bacterial count, and thus the deterioration process leading to it, can be indirectly monitored in the dairy product under study by low-frequency determination of both the dielectric constant and the loss factor

Monitoring the process of yogurt spoilage by dielectric measurements and spread plate method

In my research work, I primarily focused on the investigation of yogurt (made from home-made raw milk) spoilage by microbiological and dielectric measurements. During the experiment, I continuously monitored the changes in aerobic and anaerobic Lactobacillus cell counts of the product, as a possible spoilage process would cause the deteriorative microbes to displace the lactic acid bacteria, and I also monitored the changes in the dielectric properties of the sample material at 400 MHz frequency. The research results verified that there is a strong correlation between the variation in live cell counts and dielectric parameters in both aerobically and anaerobically cultured lactic acid bacteria. The main conclusions of the results are that the change in the bacterial count, and thus the deterioration process leading to it, can be indirectly monitored in the dairy product under study by low-frequency determination of both the dielectric constant and the loss factor

Monitoring the Acid Coagulation Process of Milk by Dielectric Measurement

The application of dielectric measurement techniques is becoming increasingly widespread in several fields of science and industry, due to its simple, quick and accurate usability. The dielectric behavior of almost all materials largely depends on – among other factors – their physical structure and chemical composition, and when these properties change even to just a relatively small extent, it can be detected by monitoring appropriate dielectric parameters. In our work, we have investigated the process of acid coagulation of milk to see whether a correlation can be established between the rheological behaviour of milk and two dielectric parameters, namely the dielectric constant, and the dielectric loss factor

Possibilities for detection of the change of biodegradability of wastewater by dielectric constant measurements

Nowadays, the development of rapid and non-destructive measurement methods have high importance. The dielectric measurement is a promising technique to detect the chemical and physicho-chemical change of different materials. The dielectric behavior of pure water is widely investigated for decades, but there is very few information available related to the dielectric parameters of wastewater. Our study aims to investigate the applicability of dielectric measurements for the detection of the change of biodegradability of wastewater. In the experiments the change of organic matter solubility and biodegradability of sugar beet processing wastewater, meat processing wastewater, dairy industry wastewater and municipal wastewater was examined. Our results show that dielectric constant - measured at the frequency of 2400 MHz - has a strong linear correlation with the soluble chemical oxygen demand (SCOD), which makes possible the fast detection of disintegration efficiency of different wastewater and sludge treatment processes, or the organic matter removal efficiency of wastewater purification technologies. Furthermore, our results verified that the change of aerobic biodegradability (expressed in BOD5/SCOD ratio) show also good linear correlation with the dielectric constant. These preliminary results enable to develop a dielectric behavior based detection method for the estimation of the efficiency of wastewater treatment processes

Microwave and ultrasound-assisted extraction of monomeric anthocyanin pigment content from plant residuals

Our investigation focused on the intensification of monomeric anthocyanin pigment content (MAC) extraction from raspberry residuals by using microwave (MW) and ultrasound (US) radiation with different solvents, and to monitor the efficacy of these processes by the assessment of the dielectric behavior of the extracts. All the experiments were carried out with using 5 grams of the raspberry raw material mixed with 100 cm3 of three different solvents – distilled water, hydrochloric acid, and the mixture of HCl and citric acid – separately. For the intensification processes, microwave and ultrasonic radiation were used in three different total irradiated energy input values: 30 kJ, 45 kJ and 60 kJ. The MAC content was analyzed according to the AOAC official method for total monomeric anthocyanin pigment content, while the dielectric behavior of the extracts was analyzed with laboratory dielectric assessment kit. Our results revealed that using MW irradiation as an intensifying process for extraction can be effectively used in the lower irradiated energy range (30 kJ), and the higher level of power (500W) is more efficient, regardless of the applied solvent. If, however, ultrasonic radiation is being used, usually the higher the energy intensity, the higher the yield of MAC can be observed. The assessment of dielectric behavior proved that a strong correlation (r=0.98-0.99) can be found between the dielectric constant (ε’) and the MAC concentration of the extracts, regardless of the intensifying method and solvent used

Monitoring the acid coagulation process of milk by dielectric measurement

The application of dielectric measurement techniques is becoming increasingly widespread in several fields of science and industry, due to its simple, quick and accurate usability. The dielectric behavior of almost all materials largely depends on – among other factors – their physical structure and chemical composition, and when these properties change even to just a relatively small extent, it can be detected by monitoring appropriate dielectric parameters. In our work, we have investigated the process of acid coagulation of milk to see whether a correlation can be established between the rheological behaviour of milk and two dielectric parameters, namely the dielectric constant, and the dielectric loss factor

Possibilities for detection of the change of biodegradability of wastewater by dielectric constant measurements

Nowadays, the development of rapid and non-destructive measurement methods have high importance. The dielectric measurement is a promising technique to detect the chemical and physicho-chemical change of different materials. The dielectric behavior of pure water is widely investigated for decades, but there is very few information available related to the dielectric parameters of wastewater. Our study aims to investigate the applicability of dielectric measurements for the detection of the change of biodegradability of wastewater. In the experiments the change of organic matter solubility and biodegradability of sugar beet processing wastewater, meat processing wastewater, dairy industry wastewater and municipal wastewater was examined. Our results show that dielectric constant - measured at the frequency of 2400 MHz - has a strong linear correlation with the soluble chemical oxygen demand (SCOD), which makes possible the fast detection of disintegration efficiency of different wastewater and sludge treatment processes, or the organic matter removal efficiency of wastewater purification technologies. Furthermore, our results verified that the change of aerobic biodegradability (expressed in BOD5/SCOD ratio) show also good linear correlation with the dielectric constant. These preliminary results enable to develop a dielectric behavior based detection method for the estimation of the efficiency of wastewater treatment processes

Application of dielectric measurement for monitoring the efficiency of enzymatic processes

The dielectric measurements have proved their applicability in many fields of science and industry practice, as well. However, there is just limited experiences in the case of enzymatic processes. Therefore, the main aim of our research was to investigate the applicability of dielectric measurements for monitoring of enzymatic hydrolysis of lactose and cellulosic biomass. During our measurements, the dielectric constant and dielectric loss factor in the frequency range of 200-2400 MHz was determined using an open-ended coaxial dielectric probe. Based on our results, it can be concluded that the decomposition of lactose can be monitored by measuring both the dielectric constant and the dielectric loss factor at frequencies of 1000 MHz and 1800 MHz, while the enzymatic degradation of cellulose can be detected by the ratio of dielectric constant values measured at 400 and 1800 MHz frequencies. Therefore, it can be concluded that determining dielectric parameters at appropriate measurement frequencies are suitable for non-destructive and rapid monitoring of the efficiency and progress of enzymatic processes