| Tomato fruit is deeply loved by people because of its unique flavor and rich nutritional value.It has become one of the fastest growing fruits and vegetables.Therefore,research on the preservation of fruit and antibacterial research of tomato fruit has also become a new field to research on fruit and vegetable.The tomato fruit has very high moisture content and thin skin,which cause tomato appear with damage in the transportation and storage process after harvest due to collision between two tomato fruits,which will provide conditions for the invasion of bacterial fungi.For tomato,the most important disease is gray mold,and its pathogen is Botrytis cinerea.The current method to control gray mold in agriculture is chemical control,but its harm also prompts people to explore new prevention and control measures continuously.In this paper,two antibacterial agents,thymol and carvacrol,will be used to study the antibacterial mechanism of tomato gray mold and the preservation of postharvest tomatoes.Investigating the effect of fresh-cut tomatoes with low temperature and antibacterial plastic wrap on quality parameters,physiological and biochemical changes in the tomato body.In vitro bacteriostatic test,the antibacterial effect of thymol and carvacrol was investigated by preliminary bacteriostatic test.The minimum inhibitory concentration and minimum bactericidal concentration of the two bacteriostatic agents were determined by agar dilution method.The MIC of thymol was 80.00 mg/L,the MBC was 100.00 mg/L.However,the MIC of carvacrol was 116.67 ?L/L,and the MBC was 166.67 ?L/L.Then,the morphological changes of the mycelium and spores of the bacteriocin treated by the bacteriostatic agent were observed by scanning electron microscopy and fluorescence microscopy.It was found that the cell structure was destroyed.Then the content of the intravital solution of the lysin,external conductivity,potassium ion,pH,lipid and fatty acid content were determined after the bacteriostatic treatment,which further confirmed that the use of bacteriostatic agents destroyed cell membrane structure of gray mold,changed its permeability,deformed the cell structure and caused leakage of the substance,so the normal growth of the gray mold were inhibited seriously.In the entity preservation experiment,the post-harvest tomato fruit was treated by using thymol and carvacrol,and it was found that both bacteriostatic agents caneffectively reduce the decay rate of post-harvest tomato.After storage for 8 days at25?,the rotting rates of the treatment groups of 8×MBC thymol and the 8×MBC carvacrol reduce 62.11% and 54.63% respectively,which were inferior to control group.At the same time,the water content,hardness,Vc content and other quality parameters were maintained to some extent,and peroxidase(POD),superoxide dismutase(SOD),catalase(CAT)and phenylalanine ammonia lyase(PAL)activities are induced.The experimental data were shown that both bacteriostatic agents can inhibit tomato quality decreasing after harvest,delaying senescence and fruit decay.In fresh-cut tomato,Vc and TA content in tomato fruits after fresh-cut treatment was lower than those in intact tomato,and the enzyme activities of phenylalanine ammonia-lyase(PAL),hydrogenase(CAT),superoxide dismutase(SOD)and total phenol content(TP)all were increased,which induced the accumulation of content of malondialdehyde(MDA).However,the experimental data were shown that low temperature and antibacterial preservative film can alleviate the loss of nutrients and the accumulation of MDA caused by fresh cutting.To a certain extent,it can delay fruit lesions and aging caused by fresh cut,reduce fruit metabolism rate,and inhibit enzyme activities,which are related to fruit browning. |
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