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

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 US-NaClO-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-NaClO-phytic acid could effectively maintain the fresh-keeping effect of fresh-cut lettuce and prolong its shelf life.