Study On The Application Of Perilla Frutescens In The Preservation Of Cherry Tomatoes

Perilla frutescens is an annual herbaceous plant in the Lamiaceae family,and it is one of the first 60 kinds of Chinese Medicine,which are both food and medicine,issued by the Ministry of Health(the National Health and Family Planning Commission).Perilla frutescens has a variety of physiological activities,and studies have shown that perilla frutescens has good preservation and fresh-keeping effects on soy sauce,meat products,brined products,and seafood,but no detailed studies have been reported on the application of fruits and vegetables.Due to the increase of pathogen resistance,environmental pollution,high residual harm to human health and other issues caused by the abuse of chemical antiseptic,and especially the pursuit of green life which has made natural preservatives becoming more and more concerned.In order to explore the application of Perilla frutescens in the preservation of fruits and vegetables,this study mensurated the preservation effect of Perilla frutescens extract on cherry tomatoes;meanwhile,the effective antibacterial components and the antibacterial mechanisms of Perilla frutescens were also studied.In particular,bacteriostasis mechanism was checked further from the microbiological quorum sensing.The main results are as follows:1.In this research,cherry tomatoes were used as test vegetables,and perilla frutescens extract was used as the test material.Cherry tomatoes were soaked with perilla frutescens extract,and they were observed and measured for 27 day at room temperature(20-25°C).The effect of perilla frutescens extract on the fresh-keeping of cherry tomatoes was as follows: Perilla frutescens extract can effectively increasethe marketable fruit rate,reduce the rotten index,maintain the fruit hardness,inhibit the oxidation of VC and increase of malondialdehyde,and this treatment can reduce the consumption of soluble solids and slow down the reduction of titratable acid content,which can effectively maintain the nutritional value of cherry tomatoes and make the fruit more edible.2.A pathogenic bacterium was isolated from the diseased fruit that caused the deterioration of cherry tomatoes.The pathogenicity test proved that this bacterium could actually cause fruit rot and the pathogenicity rate was 100%.Through the comparison and identification method of the r-DNA ITS sequence,it was found that this bacterium was 99% homologous with the Ceriporia lacerata,and by morphological identification and microscopic observation,it was found that this bacterium had the remarkable characteristics of the Ceriporia.The mycelium wall was smooth and the hyphae were distributed parallel,occasionally separated and branched.The reaction was blue after dyeing with Gossypol blue dye.Therefore,it was found that the pathogen that led to the rot of the Cherry tomatoes was Ceriporia lacerata,which was first discovered in the Cherry tomatoes.3.Determination of the effective components in Perilla frutescens and the combination use: according to the results of previous studies,whether rosmarinic acid was the main antibacterial ingredient in perilla frutescens was excavated and verified.The aqueous extracts of Perilla frutescens were detected by HPLC,and the samples were found to contain rosmarinic acid.After calculating the content of rosmarnic acid,the same concentration of rosmarnic acid standard was used to determine theinhibitory effect of the Ceriporia lacerata.The results showed that rosmarinic acid was the main active component in the aqueous extract of Perilla.The combined use of perilla frutescens and sodium benzoate had the highest inhibitory rate against Perilla frutescens at a ratio of 2:3,which was 14.8%.4.In this paper,we investigated the active ingredient rosmarinic acid in Perilla,and tried to explain the interference of rosemarinic acid to Escherichia coli from the direction of microbial community effect.The results are as follows: Rosmarinic acid was used as a signalling molecular analog of Quorum Sensing.Two methods,crystal violet and MTT method,were used to confirmed the bi-directional regulation of rosmarinic acid on the maturation or immature periods of the biofilm,and had a concentration effect: during the growth of the Escherichia coli biofilm,the rosmarinic acid had an inhibitory effect on the biofilm as the concentration raised,and had a promoting effect after the biofilm matures.