Optimization of processing parameters of low temperature plasma sterilization and its effect on quality and oxidation resistance of pear juice

Low temperature plasma sterilization as a new non-thermal sterilization technology has significant advantages. This paper intends to explore the optimal parameters of low temperature plasma sterilization on pear juice, and its effects on quality and antioxidant capacity of pear juice. Using Escherichia coli as microbial indicator, the optimal sterilization time, power supply voltage and air flow velocity to pear juice under such a technology taken sterilization rate (logN₀/N)as indicator were investigated. The results showed that the optimal sterilization technology were as followings, sterilizing time 5 min, the power supply voltage 5 kV, the air flow rate 70L/min. Under these conditions, the bactericidal rate reached 3.81 logN₀/N.Compared with the pasteurization, under the low temperature plasma sterilization, the contents of polyphenols and V_C of pear juice was higher than that of the former by 26.5% and 20.6% respectively, the scavenging capacity against DPPH radical and hydroxyl radical was higher than that of the former by 17.99% and 18.37% respectively. The low temperature plasma sterilization might be a useful method among non-thermal sterilization technology for food sterilization.