A Real-time Monitoring Technology of Non-destructive detection of Tofu with Ultrasonic and Electrical conductivity
| Autor: | Yu-Chieh Shen, 沈裕傑 |
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| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 In this study, the ohmic-heating system was set up to control the temperature of the soymilk for accurately maintain at the suitable gel temperature, then integrate an automatic detecting system by ultrasound and conductivity to monitor the gel process of soymilk with the GDL as coagulant and different concentration of the soymilk and concentration of the coagulant. The tofu samples though the soymilk-gel process was obtained with pressurized 35.89 g/cm2 and continued 30 min and explore the texture quality of tofu by the texture experiment. Different voltage (140V, 150V, 160V) was apply to the ohmic-heating system to heat the soymilk and recorded its conductivity and measurement the ultrasonic properties of the soymilk-gel process with and different concentrations (0.5%, 0.75%, 1.0% and 1.5%), different concentrations of soymilk (8°Brix, 10°Brix and 12°Brix) and temperature 70°C. The tofu samples and whey was obtained by pressurized the soymilk-gel, then measure the conductivity of the whey and analysis the tofu quality and structure of the tofu tissue by texture profile analysis (T.P.A.), puncture test and fluorescence microscopy. The results of the heating test of the ohmic-heating system show that its heating efficiency was higher in the heating rate as 3.82°C / min. The automatic detecting system shows that the conductivity of the soymilk and whey and the ultrasonic velocity and the attenuation coefficient was higher with the concentration of the coagulant. The T.P.A. and puncture test shows that the factorability, hardness, springiness, chewiness and gumminess of the tofu increased but the adhesiveness reduced with the concentration of the coagulant. Void area of the tofu was significantly increased with the concentration of the soymilk and coagulant and the ultrasonic velocity and attenuation coefficient was significantly increased with the increased void area. The correlation coefficient between coagulant concentration and whey conductivity and between ultrasonic velocity and void area of tofu were 0.90 and 0.93 which were identified as highly correlated in this study. The automatic detection system integrated the conductivity and ultrasonic in this study could be effectively applied to the non-destructive tofu quality testing and significantly maintain the consistency of tofu products with ohmic heating system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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