Study On The Preparation Of Clove Essential Oil Microemulsion And The Preservation Effect Of Compound Chitosan On Mango

Clove essential oil is a natural plant extract,and its main component is eugenol,which has anti-oxidant,anti-inflammatory and antibacterial effects.Due to its good antibacterial activity,high safety and low toxicity,it can be used as a natural preservative.But because of their evaporation,photolysis and oxidation,the rapid decomposition in the environment prevents them from exerting their biological activities,which will further reduce their practical application value.In this case,nanotechnology,as a new technology,is committed to creating and improving the nano-scale structure of essential oils through interdisciplinary research fields to improve product stability and extend its efficacy.Therefore,nanomicroemulsion is a good carrier for poorly soluble volatile essential oils.By choosing suitable surfactants with hydrophilic-hydrophobic balance（HLB）values and co-surfactants that are friendly to the environment and humans and animals,essential oils can be well dissolved in the microemulsion system and improve its stability.Chitosan is an important derivative of chitin,which is widely used in food preservation due to its broad-spectrum antibacterial,good film-forming properties,antioxidant properties and food safety.Mango is rich in sugar,crude fiber,minerals,vitamins,polyphenols,etc.and is deeply loved by people.This article first studied the preparation conditions of clove essential oil microemulsion system.The experiment took clove essential oil as the research object,and prepared clove essential oil microemulsion system constructed by different surfactants,co-surfactants and Km values.The microemulsion was optimized by pseudo-ternary phase diagram,and the results showed that: polyoxyethylene castor oil（Cremophor EL）is the best surfactant;absolute ethanol is the best co-surfactant;Km=4,mixed surface The best ratio of active agent to oil is 8:2.The configuration of the microemulsion was identified by the conductivity method.The particle size of the O/W optimized clove essential oil microemulsion was15.55±0.32 nm,PDI was 0.19±0.03,and the potential was-1.75±0.07 mV.Secondly,the stability,viscosity,anti-oxidation and antibacterial properties of clove essential oil microemulsion were further investigated.Stability tests are carried out by centrifugation,heating and storage.The results showed that the microemulsion system remained clear and transparent when the centrifugal speed was 4000,7000,10000 r/min and the heating temperature was 40,50 to 90 ℃,and there was no turbidity.There is no significant difference in particle size between storage at room temperature and 25°C for 90 days and that on day 0,and it has good stability.The rheometer proves that the microemulsion behaves as a low-viscosity Newtonian fluid,and further proves that the electrical conductivity method can identify the configuration of the microemulsion.The DPPH experiment proved that the clove microemulsion system can enhance the antioxidant capacity of clove essential oil.The antibacterial experiment proved that the clove essential oil microemulsion system can enhance the antibacterial ability of clove essential oil.Finally,the clove essential oil microemulsion was applied to the fresh-keeping experiment of mangoes.The clove essential oil microemulsion of 0.1,0.5,1 mg/mL and its chitosan and single chitosan solution were used to soak the fresh mangoes for 45 s,and wait for the mangoes to become natural.After air-drying,the fresh-keeping effect on mangoes was investigated at 25°C and 15°C.When stored at 15°C for 30 days,the weight loss rate of the0.5 mg/mL microemulsion composite chitosan group was 1.21%,the decay rate was 10.7%,and the VC content only decreased by 19.8%.The weight loss rate of the blank group was5.87%,the decay rate was 46.4%,and the VC content decreased by 38.3%.The weight loss rate of the 0.5mg/mL microemulsion group was 1.57%,the decay rate was 16.8%,and the VC content only decreased by 23.53%.The weight loss rate of the single chitosan group was4.76%,the decay rate was 37.2%,and the VC content only decreased by 35.29%.When stored at 25°C for 20 days,the change trend of each group was similar to that at 15°C.And under the two storage conditions,the 0.5mg/mL microemulsion composite chitosan group can maintain the higher activity of PPO and POD in the late stage of fruit ripening,and can also maintain the color of mango and the water in the system.The results show that the mangoes treated with 0.5mg/mL microemulsion and chitosan at the two storage temperatures have better fresh-keeping effect than the 0.5mg/mL microemulsion group and chitosan group;15℃ is more suitable for mango storage than 25℃,Extend the shelf life.