Study On Antibacterial Mechanism Of Essential Oil Of Pinus Pumila Pine Cone And Its Preparation Of Microcapsule

The pine cone of pinus pumila is a by-product of the pine plant of pinus pumila.It is rich in a variety of active substances.The pine cone essential oil contains volatile components such as terpene,ketone and aldehyde,and has antibacterial,anti-oxidant and anti-cancer effects.However,due to the characteristics of volatility and unstable nature,the essential oil will cause damage during transportation and use,so the micro-encapsulation of the essential oil is carried out,and the comprehensive utilization rate is improved under the protection of the wall material.In this paper,the pine cone of pinus pumila was used as the experimental raw material,and the essential oil of the pine cone was prepared by hydrodistillation,salt out-assisted hydrodistillation and ultrasonic-assisted hydrodistillation.The antibacterial effect,stability and antibacterial mechanism of the essential oil were investigated.The microcapsules of the essential oil of the pine cone of pinus pumila were prepared by the method of piercing-solidifying and complex coacervation.The properties and sustained release of microcapsules were studied.The results are as follows:1.The extraction of essential oil of the pine cone of pinus pumila by hydrodistillation method was carried out.The optimum extraction conditions were obtained by orthogonal test.The pulverization degree was>60 mesh,the ratio of material to liquid was 1:8,and the distillation time was 8 h.Essential oil yield of the pine cone of pinus pumila is 0.13±0.02 mL/100g.The salt out-assisted hydrodistillation method was used to extract the essential oil of the pine cone of pinus pumila,the optimum conditions were as follows:salt concentration was 4%,soaking time was 5 h,distillation time was 8 h,essential oil yield was 0.22±0.01 mL/100g.Ultrasonic-assisted hydrodistillation was used to extract essential oil of pine cone.The optimum conditions were ultrasonic power 270 W,ultrasonic time was 50 min,distillation time was 8 h,and the yield of essential oil was 0.19±0.02 mL/100g.The essential oil components of the pine cone of pinus pumila were identified by GC-MS.The essential oils extracted by hydrodistillation method had 51 kinds of substances,accounting for 83.6%of the peak area.There were 56 kinds of substances in essential oils extracted by salt out-assisted hydrodistillation,accounting for 93.8%of the peak area.There are 53 kinds of substances in essential oils extracted by ultrasonic-assisted hydrodistillation,accounting for 85.34%of the peak area.The main components of essential oils were β-pinene,limonene,a-terpineol and dragosantol.2.The three kinds of different extraction methods of the essential oil of the pine cone of pinus pumila have inhibition effects on six kinds of pathogenic bacteria.The anti-bacterial effect of the essential oil of the pine cone of pinus pumila extracted by salt out-assisted hydrodistillation method was the best.The inhibition zone diameter was 14.93±0.14 mm,MIC value was 8 μL/mL,MBC value was 16μL/mL.The antibacterial stability of essential oils showed that under acidic conditions,the antibacterial ability of essential oils was strong,while the antibacterial effect reduced under alkaline conditions,UV treatment had no significant effect on the essential oil,in temperature treatment,after 60℃ treatment,the stability of the essential oil of the the pine cone of pinus pumila was the best.At the same temperature,the longer the action time,the worse the antibacterial effect of the essential oil.3.After the bacteria were treated with essential oil,the bacteria were destroyed,and there was a time lag in the logarithmic phase,and even the phenomenon of stopping growth appeared,which caused Na+.K+ extravasation,increased electrical conductivity,increased soluble sugar and protein in bacterial liquid,and the inhibition of bacterial phosphorus metabolism,ATPase activity and protein synthesis;the cells showed wrinkles,with rough surface and fracture.The essential oil of the pine cone of pinus pumila significantly affected the normal growth and metabolism of the bacteria.4.The microcapsules were prepared by the method of piercing-solidifying.The optimum process was sodium alginate concentration of 2.69%,core wall ratio of 3.13,emulsifier concentration of 1.83%,calcium chloride concentration of 2%,and immobilization time of 120 min,the embedding rate was 81.33%.The microcapsules were prepared by complex coacervation method,gelatin/arabum as wall material.The optimum process was emulsifier concentration is 2%,emulsification speed is 10000 r/min,emulsification time is 3 min,wall material ratio of 0.62:1,wall material concentration of 1.65%,core wall ratio of 1.09:1,complex coagulation time of 30 min,recondensation temperature of 40℃,immobilization time of 120 min,and water addition volume was 0.5 times and the embedding rate was 71.40%.5.The results of microcapsule physical properties showed that the microcapsules prepared by the method of piercing-solidifying have relatively high water content,general solubility and large particles.The microcapsules prepared by the complex coacervation method had low water content,high solubility and small particle size.By Fourier infrared spectrum analysis,the results showed that there was no other chemical interaction between the wall material and the core material except for the physical interaction between the chemical bonds existing between the wall materials.The morphology of the microcapsules was observed by scanning electron microscopy,which was spherical and had no cracks on the surface.Thermo gravimetric analysis showed that microencapsulation could effectively delay the volatility of essential oils and was stable at room temperature.