Effects Of Natamycin On Inhibiting Of Molds And Physiological Properties Of Fresh-cut Lettuces

In the research, fresh lettuces were used as materials. After fresh-cut the lettuces weredipped in and sprayed with natamycin at200mg/L, and the effect of natamycin onphysiological propertie and the population of molds of fresh-cut lettuces was invesgated.The result showed as below:1. The increasing of molds population was significantly inhibited by natamycintreatment, and the population of molds on the surfaces of fresh-cut lettuces treated withnatamycin was less than the control in the following5-15d, indicated that natamycintreatment can be used for controlling the decay of fresh-cut lettuces. Both of dipping andspray treatment had a good effect on controlling the population of molds, and the effect ofspray treatment was superior to the dipping treatment.2. Natamycin treatment inhibited the reducing of SSC, anthocyanin, soluable proteinand chlorophyll content, delayed the accumulation of MDA, and maintained the integrity ofthe cell membrane of fresh-cut lettuces.3. The activities of PPO and LOX decreased after natamycin treatment. The activitiesof PPO and LOX in fresh-cut lettuces increased at early stages of storage, and decreased atlater stages. The activities of PPO and LOX of fresh-cut lettuces treated with natamycinwere lower than the control, the lowest PPO activity was found in natamycin treatedfresh-cut lettuces.4. The activities of POD, CAT and APX increased after natamycin treatment. Theactivities of POD and CAT in fresh-cut lettuces increased at early stages of storage, anddecreased at later stages. The activities of APX decreased at the whole storage, and thehigher APX activity was found in natamycin treated fresh-cut lettuces.5. Natamycin treatment significantly increased the content of total phenolic, flavonoidand xylogen, however, the activity of PAL was inhibited by natamycin treatment. Thephenomenon may be related with feedback regulation of the metabolite in lettuces inhibitedthe increasing of PAL activity.In conclusion, the natamycin treatment had a positive effect on decreasing thepopulation of molds, inhibiting the activity of browning pertinent enzymes andmaintainning the quality of fresh-cut lettuces.