Effect of High Voltage Pulsed Electric Field Synergised with Vanillin on the Bactericidal Effect and Quality of Raspberry Juice Assisted by Medium Temperature

本研究旨在探讨中温辅助高压脉冲电场(PEF)-香草醛复合杀菌技术(PVT)对树莓汁的杀菌效果及品质影响。通过探究电场强度、香草醛浓度、水浴温度及处理时间对微生物的致死效果，系统评估其对树莓汁的营养成分保留及贮藏稳定性的作用。结果表明，PVT处理对菌落总数(TVC)和酵母菌、霉菌总数(TYMC)的致死效果显著。贮藏实验显示，25℃条件下，PVT处理组在40天内微生物指标符合国家标准，货架期较热处理组(HT)延长一倍。品质分析表明，PVT显著提升总酚和蛋白质含量，但对花色苷的保留略低。此外，PVT对多酚氧化酶(PPO)和过氧化物酶(POD)活性的抑制率达98%和96%，接近HT组，同时有效维持果汁澄清度。该技术为树莓汁的非热杀菌及品质保持提供了新策略。The aim of this study was to investigate the effect of medium-temperature-assisted high-voltage pulsed electric field (PEF)-vanillin composite sterilisation technology (PVT) on the sterilisation and quality of raspberry juice. The lethal effects of electric field strength, vanillin concentration, water bath temperature and treatment time on microorganisms were investigated, and their effects on nutrient retention and storage stability of raspberry juice were systematically evaluated. The results showed that the lethal effect of PVT treatment on total colony count (TVC) and total yeast mould count (TYMC) was significant. The storage experiment showed that the microbiological indexes of the PVT-treated group complied with the national standards within 40 days at 25˚C, and the shelf-life was doubled compared with that of the heat-treated group (HT). Quality analysis showed that PVT significantly enhanced total phenol and protein contents, but retained slightly lower retention of anthocyanin. In addition, PVT inhibited polyphenol oxidase (PPO) and peroxidase (POD) activities by 98% and 96%, which were close to those of the HT group, while effectively maintaining juice clarity. This technique provides a new strategy for non-thermal sterilisation and quality maintenance of raspberry juice.