不同杀菌方式对龙眼原汁品质的影响

为了探讨不同杀菌方式在达到商业杀菌要求的基础上对龙眼原汁营养成分及理化性质的影响，以广西南宁地区所产的“石硖”龙眼为原料，对比分析了巴氏杀菌(PS)、微波杀菌(MS)、超高温瞬时杀菌(UHT)和高压脉冲电场杀菌(PEF)4种杀菌方式对龙眼原汁的菌落总数、色差、pH值、可溶性固形物、总酚、糖组分及有机酸等指标的影响。结果表明：4种杀菌方式均能达到商业无菌要求，对龙眼原汁的pH值和葡萄糖含量无显著性影响(p>0.05)；与对照组(CK)相比，PEF杀菌对龙眼原汁中L*值、b*值、可溶性固形物(TSS)、果糖、总糖、酒石酸、富马酸含量影响不显著(p>0.05)；与PS、MS和UHT杀菌相比，PEF杀菌对龙眼原汁中的总酚、抗坏血酸、总酸的影响幅度较小。因此，PEF杀菌技术不仅具有较好的杀菌效果，而且能更好地保持龙眼汁原有的色泽和营养品质。

Effect of Sterilization Methods on the Quality of Longan Juice

The effects of different sterilization methods on nutrient composition and physiological and biochemical  characteristics of longan juice were studied under the condition of commercial asepsis. Shixia longan from Nanning was used as the raw materials, and the effects of pasteurization (PS), microwave sterilization (MS), ultra high temperature treatment (UHT), and pulsed electric field (PEF) on bacteria number, color, pH value, soluble solid content, total phenol, sugar and acid compositions in longan juice were determined. Results indicated that all the four sterilization methods could meet the requirement of commercial asepsis, and had no significant effect on pH and glucose content of longan juice(p>0.05). Compared with the control group (CK), PEF sterilization had no significant effect on the L* value, b* value, soluble solid (TSS), fructose, total sugar, tartaric acid and fumaric acid content in longan juice (p>0.05). Compared with PS, MS and UHT, PEF had the least impact on total phenol, ascorbic acid and total acid. Therefore, PEF sterilization technology not only has a better germicidal effect, but also can better maintain the original color and nutritional quality of  longan juice.