超声-次氯酸钠-植酸联合处理提高鲜切生菜的保鲜效果

Improvement the Fresh-keeping Effect of Fresh-cut Lettuce by US-NaClO-phytic Acid

本文从自来水、超声波、微酸性电解水、超声波结合微酸性电解水、超声波结合植酸、次氯酸钠结合植酸、超声-次氯酸钠-微酸性电解水联合处理和超声-次氯酸钠-植酸联合处理8种方法中选出对鲜切生菜清洗后抑菌效果最好的方法超声-次氯酸钠-植酸联合处理,测定该方法处理后的鲜切生菜在贮藏期间的品质指标,以无菌蒸馏水作为对照。探讨超声-次氯酸钠-植酸联合处理对鲜切生菜表面大肠杆菌O157:H7抑菌效果和贮藏品质的影响。结果表明,超声-次氯酸钠-植酸联合处理的抑菌效果最好,抑菌率达到99.97%。处理后的鲜切生菜在贮藏第14 d,质量损失率为3.45%,总色差为5.39,Vc含量为2.93 mg/100 g,叶绿素含量为0.56 mg/g,水分含量为90.54%,均优于对照组;与对照组相比,过氧化物酶和多酚氧化酶活性被有效抑制,总酚含量保持较高的水平。因此,超声-次氯酸钠-植酸联合处理有利于提高鲜切生菜表面大肠杆菌O157:H7的抑菌效果和改善鲜切生菜的贮藏品质。综上表明,超声-次氯酸钠-植酸联合处理可以有效提高鲜切生菜的保鲜效果,延长货架期。

In this study,the best antibacterial method"US-NaClO-phytic acid"for fresh-cut lettuce after cleaning was selected from 8 methods included tap water,ultrasound(US),slightly acidic electrolyzed water(SAEW),US combined with SAEW,US combined with phytic acid,NaClO combined with phytic acid,US-NaClO-SAEW,and US-NaClO-phytic acid,and the quality indexes of fresh-cut lettuce treated by US-NaClO-phytic acid during storage were measured and sterile distilled water was used as a control.The antibacterial effect of US-NaClO-phytic acid on Escherichia coli O157:H7(E.coli O157:H7)as well as on the storage quality of fresh-cut lettuce were investigated.The results showed that USNaClO-phytic acid had the best antibacterial effect and the inhibitory rate reached 99.97%.On the 14th day of storage,fresh-cut lettuce treated by US-NaClO-phytic acid had the mass loss rate of 3.45%,the total color difference of 5.39,the Vc content of 2.93 mg/100 g,the chlorophyll content of 0.56 mg/g,and the moisture content of 90.54%,which were all better than those of the control group.Compared with the control group,the peroxidase and polyphenol oxidase activities were effectively inhibited,and the total phenolics content remained the higher level.Therefore,US-NaClO-phytic acid can improve the antibacterial effect on E.coli O157:H7 and the storage quality of fresh-cut lettuce.In conclusion,US-NaClOphytic acid could effectively maintain the fresh-keeping effect of fresh-cut lettuce and prolong its shelf life.