Study On The Control Effect Of Sodium Dehydroacetate And Butyl Hydroxyanisole On Kiwifruit Soft Rot

The serious occurrence of soft rot during the storage and transportation of kiwifruit restricts the development of kiwifruit industry to a certain extent.Existing prevention control methods are mainly based on chemical agents,but the use of chemical agents is easy to cause food safety problems.Hence,it is urgent to find safe and efficient prevention methods.Food additives are a class of substances that guarantee food safety and hygiene in the food industry.Based on the antibacterial and anti-corrosive effects of food additives,sodium dehydroacetate（SD）and butyl hydroxyanisole（BHA）were selected in this study based on the pre-screening of a large number of food additives in our laboratory.Two food additives were applied to conduct bacteriostasis experiment in vitro,and in vivo and field control on kiwifruit soft rot,caused by Botryosphaeria.dothidea.The main conclusions are as follows:1.Both SD and BHA could significantly inhibit the growth of B.dothidea in vitro.The EC₅₀values of SD and BHA against B.dothidea were 0.0233 g/L and 0.0275 g/L,and EC₉₅values were 0.0884 g/L and 0.1418 g/L,respectively.In the spore germination test,the conidial germination rate of SD treatment was about 50%and 7%,and BHA treatment was about 34%and 5%under the concentration of EC₅₀and EC₉₅,respectively.Relative conductivity,nucleic acid protein leakage and Alkaline phosphatase activity revealed that the cell membrane and cell wall of B.dothidea mycelia were damaged after treatment by SD and BHA.Furthermore,Transmission electron microscopy（TEM）observations results demonstrated that the intracellular mitochondrial structure was damaged and the number of mitochondria increased after SD treatment.Meanwhile,an irregular septum appears and cell wall was significantly thickened after BHA treatment.The inhibition rate of SD and BHA against D.actinidiae,C.gloeosporioides,P.microspora and other pathogenic fungi reached 100%under the EC₉₅concentration treatment.2.In vivo conditions,the incidence of soft rot and the diameter of diseased spot of kiwifruit were significantly reduced after inoculation with SD or BHA.On the 5th day after inoculation,the incidence of soft rot was reduced to 52%and the inhibition rate was46%after SD treatment at a concentration of 200×EC₅₀.Meanwhile,BHA has a low incidence of soft rot and the higher inhibition rate up to 38%and 60%,respectively.Both treatments can significantly reduce the diameter of diseased fruit spots.3.The results of field tests on SD and BHA indicated that the effect of spraying SD on the prevention and control of soft rot during postharvest storage was not significant.Compared with that of the solvent control group,the incidence of soft rot during postharvest storage was reduced by 38%by BHA spraying.However,the pre-harvest spray treatment had no significant adverse effect on the quality of kiwifruit.The results of post-harvest soaking experiment illustrated that soft rot rate decreased after SD and BHA soaking,but there was no significant difference compared with the blank control group,and there was no adverse effect on kiwifruit quality.In conclusion,SD and BHA treatments can significantly inhibit the growth of B.dothidea,and have the potential to be developed as safe and effective kiwifruit control agents,According to above experiment results and it provide a certain reference for the study of food additives for the prevention and control of postharvest diseases of fruits and vegetables.