低温等离子体杀菌工艺的优化及其对梨汁品质和抗氧化活性的影响

低温等离子体杀菌是一种新兴的非热杀菌技术,本文拟探明基于低温等离子体杀菌的梨汁适宜杀菌工艺及其对梨汁品质和抗氧化能力的影响。以大肠杆菌为微生物指标,研究低温等离子体的杀菌时间、电源电压和空气流速对梨汁杀菌率(以logN₀/N计)的影响,并采用响应面法选出最优杀菌工艺。结果表明,低温等离子体杀菌的最优工艺为:杀菌时间5 min,电源电压为5 kV,空气流速为70 L/min,其杀菌率达到3.81 logN₀/N,能够将全部大肠杆菌杀灭。与巴氏杀菌相比,经低温等离子体杀菌处理的梨汁多酚和维生素C的含量分别比前者高26.5%和20.6%,较好的保持了梨汁色泽,对DPPH自由基和羟自由基的清除能力分别比前者高17.99%和18.37%。低温等离子体杀菌是一种具有良好应用前景的非热杀菌方式。

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.