本文研究了果糖-赖氨酸模型体系美拉德反应产物（MRPs）结合脉冲电场处理（PEF）在香蕉汁低温加工中的护色和杀菌作用。首先考察了MRPs对香蕉多酚氧化酶（PPO）的活性抑制及香蕉打浆后颜色的变化。其次，考察了MRPs与PEF（单独或结合处理）对金黄色葡萄球菌和大肠杆菌的最低抑菌浓度（MIC值）、最低杀菌浓度（MBC值）的影响。研究发现，0.0625 mg/mL的MRPs可使香蕉PPO活性下降86%且可保证香蕉打浆后30 min内维持原有色泽。MRPs对金黄色葡萄球菌和大肠杆菌的MIC值均为12.5 mg/mL。PEF对上述两种微生物有着良好的钝化效果，且可显著增强MRPs的抑菌效果，即金黄色葡萄球菌和大肠杆菌经30 kV/cm电场强度处理1200 μs后可使MRPs对二者的MIC值分别降至1.56 mg/mL和3.125 mg/mL。添加0.0625 mg/mL MRPs护色打浆，经酶解过滤后所得滤液在50 kV/cm 电场强度条件下处理1200 μs可得到颜色亮黄、风味纯正且保藏期较为理想的香蕉汁产品。

The anti-browning and anti-microbial effects of Maillard reaction products (MRPs) in fructose-lysine model system and pulsed electric field (PEF) treatment during the low-temperature processing of banana juice were investigated in this study. First, the impact of the MRPs in inhibiting banana polyphenol oxidase (PPO) activity and color changes after pulping banana fruits were investigated. Second, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MRPs with and/or without PEF against Staphylococcus aureus and Escherichia coli were measured. The results showed that the addition of 0.0625 mg/mL MRPs decreased PPO activity by 84% and retained the original color of banana fruits for 30 minutes after pulping. The MICs of MRPs against S. aureus and E. coli were both 12.5 mg/mL. PEF effectively inactivated S. aureus and E. coli, significantly enhancing the anti-microbial effects of MRPs. Specifically, the MICs of MRPs against S. aureus and E. coli decreased to 1.56 mg/mL and 3.125 mg/mL, respectively, after PEF treatment at 30 kV/cm for 1200 μs. MRPs at a concentration of 0.0625 mg/mL in combination with PEF at 50 kV/cm for 1200 μs while pulping the banana fruits produced banana juice with a bright yellow color, a pure flavor, and a desired shelf life.

国家自然科学基金青年科学基金项目(31101328)；中国热带农业科学院院基本科研业务费(1630052014005)