Experimental Study On Antibacterial And Antioxidant Effects Of Rosmarinic Acid In Asparagus Products

Objective:This study based on the experiment of Yuanjiang boiled asparagus,which were screened out the main dominant bacteria in the natural conditions.By comparing the effects of rosmarinic acid and traditional chemical preservatives,Study on the antibacterial and preservative effects of rosmarinic acid on Yuanjiang Asparagus.Method:The Yuanjiang boiled asparagus natural mildew in room temperature conditions,through the comparison of mold fungi in different culture medium on the growth of different basis of selecting suitable medium as the medium for the growth of bacteria and mildew,and using apagoge to verify the rationality of screening dominant spoilage bacteria.DNA sequencing method was used to identify the main types of spoilage bacteria by homology with known sequences in NCBI Gen Bank.The inhibitory effect of rosmarinic acid on the main spoilage bacteria was determined by double dilution method and Oxford cup method.Study on the stability and oxidatio n resistance of rosmarinic acid.Result:The PCA and PDA medium were selected as the medium for the growth of mycobacteria by comparing the differences in the growth of moldy bacteria on different cultures.The results showed that the main mildew fungi were X1,X2,X3,Z1,Z2,Z3,and the growth rate of the dominant fungi was different,the 16s r DNA or ITS region of the unknown strain was amplified by primers PCR at both ends of the ITS region and 16sr DNA of fungi.The DNA was sequenced and compared with t he known sequence in NCBI Gen Bank.X3,Z1:Enterobacter cancerogenus strain LMG 2693;Z2:Geotrichum candidum culture-collection CBS:11628;Z3:Trichoderma longibrachiatum voucher NFCF081,Z2:Geotrichum candidum culture-collection CBS:11628;Z3:Trichod erma longibrachiatum voucher NFCF081.The MIC and MBC values of rosmarinic acid were studied by the ratio dilution method.Results:The MIC values of rosmarinic acid for X1,X2,X3,Z1,Z2 and Z3 were 4mg/ml,8mg/ml,8mg/ml,4mg/ml,8mg/ml,4 M g/ml.The MBC values of rosmarinic acid for X1,X2,X3,Z1,Z2,Z3 were8mg/ml,16mg/ml,16mg/ml,8mg/ml,16mg/ml,8mg/ml.In this study,X3 was used as the research object,and the dilution was selected in pre-experiment.Oxford cup method wa s used to determine the inhibition zone of rosmarinic acid.Results:(1)Under different p H conditions,rosmarinic acid had a larger diameter than that of sodium benzoate,which the antibacterial range was wide,and the inhibition zone reached 15.37mm at p H 4.(2)After 1h of rosmarinic acid treatment at different temperatures,we could see that from 20?to 40?,the inhibition zone gradually decreased,and between 40?and 100?,the inhibition zone did not change.(3)In the UV irradiation treatment,the antiba cterial effect of rosmarinic acid was decreased under the irradiation of 0?12h,and after 12?24h,the bacteriostasis of rosmarinic acid basically remained the same.(4)In the determination of DPPH ability of rosmarinic acid,the DPPH free radical scavenging rate increased gradually with the increase of the dosage of different antioxidants at 1mg/m.(5)In the determination of ABTS~+antioxidant activity,when rosmarinic acid was at the concentration of 0.3mg/ml,the advantage of its antioxidant activity wa s 2.79 times of the Trolox,compared to Trolox and vitamin C.The effect of rosmarinic acid on the freshness of boiled asparagus was studied.The p H of boiled asparagus was decreased within 0 to 12 days,and the changing trend was different within 3 to 12 days.At the same concentration,with the increase in the number of storage days,the total number of bacteria gradually increased to no counting.Under different concentration conditions,the greater the concentration of rosmarinic acid,the stronger power of asparagus bacteria inhibbition.Indicating that rosmarinic acid in the asparagus preservation has a certain role.Conclusion:The main dominant spoilage bacteria could be isolated by screening the asparagus.Rosmarinic acid has some advantages in the field of antisepsis and preservation was studied on this study.The experimental provides a basis for the application of Yuanjiang Asparagus.