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Abstract
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This study aims to investigate the simultaneous effect of fluid pressure, vacuum pressure, and fluid temperature in the microfiltration process of tomato juice. For this purpose, a microfiltration device with ceramic filter under pressure-vacuum combination was developed, followed by investigating and optimizing the effect of variables of this device for the tomato juice microfiltration process. The microfiltration process of samples was performed in five fluid pressure levels of 1, 1.5, 2, 2.5, and 3 bar, five vacuum pressure levels of 5, 25, 45, 65, and 85 kPa, and five fluid temperature levels of 20, 30, 40, 50,and 60°C. Statistical analysis of the data and optimization of the tomato juice microfiltration process was performed using the response surface methodology (RSM). The results showed that a ceramic filter with a pore size of 0.2μm was a good option for the microfiltration of tomato juice. Such size reduced the share of insoluble particles larger than 0.2 μm in tomato juice to 0.1% and, as a result, lowered the turbidity of tomato juice from 643NTU to 12NTU. The results showed the statistically significant effects of fluid pressure, vacuum pressure, and fluid temperature on the variables of permeate flux response and total energy consumption, as well as the effects of fluid pressure and fluid temperature on the response variables of lycopene and vitamin C content of tomato juice microfiltration. Optimal conditions of the microfiltration process of tomato juice were achieved at a fluid pressure of 2 bar, the vacuum pressure of 5 kPa, and fluid temperature 26°C with a desirability index of 0.967. Under the optimal conditions, values of response variables including permeate flux, total energy consumption, lycopene, and vitamin C content of tomato juice filter were equal to 215.09×10 -6 m 3 m -2 s -1 , 0.044 kWh, 2.42 mg 100g -1 , and 13.21 mg 100g -1 , respectively.
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