| In this research,the bacteriostatic activities of 3 plant crude extracts inhibition with 3 major tropical fruit main pathogenic bacteria were determined and screened,and the best effect of inhibitor bacteria plant was selected.Then the suitable concertration of essential oil for inhibiting papaya anthrax were explored.Finally,the effect of essential oil on storage quality and freshness keeping for papaya fruits(zhongbai)at room temperature(RT)storage conditions were investigated by the method of whole fruit,peduncle fumigation and compound essential oil so as to provide theoretical basis for the development of the biological fruit and vegetable fresh-keeping agent.The main contents and the results of this paper were as follows:1.The antifungal activities of the crude extract from CL,Chinese Wedelia and papaya seeds for 3 major tropical fruit main pathogenic bacteria were tested with the method of growth rate.The results indicated that the extract from CL was more effective on antifungal activity than the other extract.2.Steam distillation extraction was used to extract volatile oil from leaves and peel of CL.And the essential oil of CL were tested with the method of growth rate,and the results indicated that bacteriostatic effect increased with the increase of concentration of essential oil,but too high concentration would promote the growth of the pathogen.And the essential oil of CL at 2.0 μ L/m L for papaya anthracnose were 92.50%,it was more effective on antifungal activity than the other concentration of essential oil.3.The essential oil from CL on fresh-keeping of Papaya fruits at ambient temperature can maintain higher storage quality of the Papaya fruits and can extend the storage time.This research adopts the whole fruit,peduncle fumigation and compound essential oil.Results showed that the disease index of papaya fruits were inhibited obviously by 10 μL/L,2 μL and 40 μL/L essential oil of CL treatment.In addition,the essential oil also delayed the decrease of total soluble solids(TSS),hardness and vitamin C(VC)in fruit tissue,significantly reduced moisture loss,increased superoxide dimutase(SOD)and Peroxidase(POD)activity,and also significantly inhibited the increase of malondiadehyde(MDA)content and relative conductance.4.The method of GC-MS technique was used to isolate and identify the chemical constituents of volatile oil,peak area normalization method was applied to determinate the relative percentage content of main component.The results showed the main components were alpha farnesene,caryophyllene and oxygen-containing derivatives such as aldehyde and ester and alcohol.The predecessor had confirmed that antibacterial ingredients such as caryophyllene oxide,nerolidol,alpha-cedrene and alpha-famesene had great effective on antifungal activity.The essential oil of CL has good antibacterial effect and preservation effect on papaya anthrax and papaya fruit.It is easy to be got in Hainan province.It is expected to become a new fresh-keeping agent on fruits and vegetables in the future. |
