脉冲放电等离子体杀灭苹果汁中鲁氏接合酵母及对苹果汁品质的影响

Effect of Pulsed Discharge Plasma on the Inactivation of Zygosaccharomyces rouxii in Apple Juice and Quality of the Juice

摘要:

应用研制的脉冲放电等离子体杀菌设备，以鲁氏接合酵母（Zygosaccharomyces rouxii，Z.rouxii）为试验菌株，探讨电气参数（脉冲电压、通气量和处理时间）、溶液参数（果汁可溶性固形物）及菌初始浓度对苹果汁中鲁氏接合酵母的杀灭影响，并比较了不同菌株杀灭效果的差异；同时对处理前后苹果汁的基本理化指标、有机酸、多酚及挥发性风味物质含量进行测定，探讨脉冲放电等离子体对苹果汁品质的影响。结果表明：在脉冲电压24 kV、通气量150 mL/min、果汁可溶性固形物12%和果汁pH=3.84时，脉冲放电等离子体能够将初始浓度为1.08×104 CFU/mL的鲁氏接合酵母LB在5 min内杀灭。同时脉冲放电等离子体对苹果汁基本理化指标、有机酸、多酚及挥发性风味物质含量大部分影响均不显著（p<0.05），能够较大程度保持苹果汁品质，该研究为脉冲放电等离子体在食品杀菌中应用提供了重要依据。

Abstract:

A self-assembled pulsed discharge plasma device was developed and Zygosaccharomyces rouxii LB was used as the test strain to study the effects of electrical parameters (voltage, ventilation, and exposure time), solution parameters (soluble solid concentration), and the initial concentration of the Z. rouxii LB on its inactivation in apple juice. The differences in the inactivation effects on different strains of Z. rouxii were compared. Moreover, the effects of pulsed discharge plasma on apple juice quality were studied by measuring the major physicochemical indexes, and the contents of organic acids, polyphenols, and volatile flavor compounds. The results showed that when juice-soluble solid concentration, juice pH, pulse voltage, and ventilation were 12 %, 3.84, 24 kV, and 150 mL/min, respectively, the Z. rouxii LB with an initial cell concentration of 1.08×104 CFU/mL could be effectively inactivated in five minutes by the pulsed discharge plasma. The pulsed discharge plasma had no significant effect on the basic physicochemical indexes, and the contents of organic acids, polyphenols and volatile flavor substances of apple juice (p<0.05), and therefore could essentially maintain the apple juice quality. This study may provide an important methodological basis for the application of pulsed discharge plasma in food sterilization.