| A strong aroma and bitter taste mark Artemisia(Artemisia L),while its essential oil has antibacterial,antioxidant,and insecticidal properties.It is used widely in the human disease control and pharmaceutical industries.Pepper that has been postharvested is susceptible to pathogenic bacteria and decays rapidly,which reduces its nutritional value.Therefore,this paper studies the characteristics of four kinds of essential artemisia plant oils as well as their bacteriostatic performance against capsicum bacteria.the analysis of ascorbic acid in chili,total phenols and flavonoids as well as changes in the physiological indexes,evaluation of the preservation effects of essential oils,provides both theory and data to support artemisia plant essential oil’s use in fruits and vegetables preservation,the main contents are as follows:1.GC-MS analysis of four essential oils of Artemisia showed that the total content of each essential oil was more than 99%,terpene-4-ol,β-caryophyllene and 1,8-Cineole were common compounds.The antioxidant strength of the four plant essential oils is Artemisia.annua > Artemisia.scoparia > Artemisia.giraldii > Artemisia.anethoides.Through sensory evaluation analysis,among the four kinds of essential oil sensory evaluation,Artemisia fragrance score was the highest,fruit aroma and acid aroma score was the lowest,and the compounds around sensory properties contributed greatly to the odor of essential oil.2.Based on this study,13 microorganic strains were isolated from rotten pepper fruits to find out postharvest pathogens of peppers;4 kinds of bacteria and 2 kinds of fungi were identified as the postharvest pathogens in pepper through Koch’s postulates.The results of DNA sequencing combined with morphological observation showed that the six strains were Bacillus subtilis,Pectobacterium carotovorum,Pectobacerium aroidearum,Bacillus stratosphericus,Fusarium chlamydosporum and Alternaria angustiovoidea.After being cultured in the medium with different p H,salt gradient and temperature for 12 hours,the four kinds of bacteria could grow to the normal range,and the chemotactic test showed that CEP4 strain could grow normally in root,stem,leaf and fruit extract.3.Four Artemisia essential oils and 1,8-Cineole were tested in vitro for bacteriostatic properties.The results showed that Artemisia essential oil had strong antibacterial activity,and A.scoparia essential oil,A.annua essential oil and 1,8-Cineole were suitable as freshkeeping materials.Study findings,the MIC,MBC and EC50 values of A.annua and A.scoparia essential oil and 1,8-Cineole to bacteria were determined to are between 1.25-15μg/mL and 5.38-26.25μg/mL.It was observed by scanning electron microscope that essential oil and monomers could destroy the cell wall of bacteria,resulting in exudation of the content material and wrinkling and breaking of the surface.The results of in vivo protection and treatment showed that A.scoparia essential oil and 1,8-Cineole were good postharvest fresh-keeping materials.4.The physiological indexes of the experimental materials were determined in vivo.When the pepper was infected by pathogenic bacteria,the physiological indexes such as malondialdehyde,soluble protein,total phenols and flavonoids were determined at different processing times.Compared with the control group,the results showed that both A.scoparia essential oil and 1,8-Cineole could prolong the shelf life of pepper fruit,prevent the quality decline and protect the nutrients in the body. |
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