Preliminary Studying The Influence Of Ohmic Heating On The Sterilization Effect Of Yeast And The Nutrient Components In The Soybean Sauce

The article preliminary studys the influence of ohmic heating on the sterilization effect of yeast and the nutrient components in the soybean sauce.The study provids a new solution to solve the problem of market soybean sauce bulging in bags or bottles. Experimental results show as follows:1. Under the low-temperature (20～70℃)and low-voltage(35 V) condition, The soybean sauce electrical conductivity and the temperature have the linear relation; with the solid content reduced, the conductivity increases, and the conductivity coefficient in linear equation changes more, the rate of electrical conductivity increases faster; under the condition of the same solid content, as the salt content adds, as the conductivity increases faster; voltage change has no effect on the conductivity.2. In the ohmic heating process, the soybean sauce temperature rising has an exponential growth with time, and different points of the temperature rising are more evenly; the temperature rising is faster with the voltage increased(25~40V); with the solid content reduced, the rate of the temperature rising is faster; under the low-temperature (20～70℃)and low-voltage(35 V) condition, the exponential growth trend is similar to the linear.3. with increasing of the voltage, the sterilization time and the heating temperature, the survival rate of yeast decreases; ammonia salt content, amino nitrogen content, reducing sugar content, pH value and the total acid content show the different trends with the voltage, the sterilization time and the heating temperature changed; through the orthogonal test, deciding the optimal conditions for sterilization: sterilization temperature of 65℃, sterilization time of 150 s, sterilization voltage of 35 V; under these conditions, the yeast is basically sterilized in the soybean sauce, the ammonia content is increased 286 percent, the loss rate of amino nitrogen content is 1.79 percent, the loss rate of reducing sugar content is 4.01 percent, electric power consumption is about 785 J / kg ? s.4. The experiment compares the ohmic heating with conventional water heating. After the conventional water heating, pH reduces 2.81%, total acid increases 0.98%, ammonia content increases 439%, amino nitrogen content reduces 3.42%, reducing sugar content reduces 21.86%; but after the ohmic heating, pH reduces 2.25%, total acid reduces 3.13%, ammonia content increases 286%, amino nitrogen content reduces 1.79%, reducing sugar content reduces 4.01%; preliminary study shows that ohmic heating has lower effect on the nutritional content.5. Estimating the utilization of geothermal energy in the ohmic heating is more than 80 percent, relative high utilization of geothermal energy.