Preparation Of Microcapsules Of Saffron Petal Essential Oil By Recondensation Method And Preparation Of Antibacterial Cotton

In recent years,more and more attention has been paid to textiles with antibacterial properties.Natural plant essential oil has excellent natural antibacterial properties and can be used in the preparation of natural antibacterial textiles.However,essential oil cannot be directly applied to textiles due to its strong volatility and poor thermal stability.Therefore,it is particularly important to develop a natural green and stable antibacterial agent for essential oil to be applied to textiles.Saffron petals belong to agricultural waste,which is mainly used in animal husbandry feed.The aim of this paper is to use the recovered saffron petals and extract essential oil,improve the utilization rate of resources,and improve the overall economic benefit of saffron.In this paper,the antibacterial performance of saffron flower petal essential oil was investigated,and the antibacterial performance of saffron flower petal essential oil microcapsules（SPEO-Ms）in antibacterial cotton was investigated by microencapsulation technology.The main research results are as follows:（1）The extraction rates of 0.17%,2.05%,2.57%and 20.80%by steam distillation and organic solvent extraction（n-hexane,petroleum ether,ethanol）at 8 h and 48 h,respectively.The optimum extraction conditions of organic solvent（ethanol）extraction were as follows:extraction time 48h,solid-liquid ratio 1:10,and diameter of saffron petals 40 mesh.（2）Escherichia,coli Staphylococcus aureus and Candida albicans were selected as the test strains,and AGAR inhibition circle method was used to investigate the antibacterial performance of saffron petal essential oil extracted by different extraction methods.The results showed that the antibacterial properties of SPEO prepared by different extraction methods were different.The SPEO extracted by n-hexane had no significant inhibitory effect on the three tested bacteria,while the SPEO extracted by steam distillation and petroleum ether had significant inhibitory effect only on Staphylococcus aureus.The diameter of inhibitory zone was 12.1±0.7mm and11.2±0.6mm,respectively.However,SPEO extracted with organic solvent（ethanol）had obvious inhibitory effect on all three tested strains,especially on Candida albicans.The diameter of inhibitory zone reached 16.1±1.1mm.（3）The SPEO extracted by steam distillation and organic solvents（n-hexane,petroleum ether,ethanol）were analyzed by gas chromatography-mass spectrometry.A total of 22components were identified by steam distillation,among which n-hexadecanoic acid（25.33%）accounted for the highest proportion.A total of 25 components were identified in the extract obtained by organic solvent extraction（n-hexane）,among which the highest content was hexadecane（26.51%）.A total of 18 components were identified in the extract obtained by organic solvent extraction（petroleum ether）,among which the proportion of tetradecane（14.71%）was the highest.A total of 18 components were identified in the extracts prepared by organic solvent extraction（ethanol）,among which 4h-pyrano-4-1,2,3-dihydro-3,5-dihydroxy-6-methyl-（24.81%）was the highest.The extracts of the four extraction methods all contain n-hexadecanoic acid and linoleic acid,and 4h-pyrano-4-1,2,3-dihydro-3,5-dihydroxy-6-methyl（DDMP）,octadecanol and other components in the ethanol extract have been shown to have strong biological activities.The comparative analysis is that the synergistic action of the above active substances in SPEO prepared by organic solvent extraction（ethanol）makes it have certain antibacterial activity.（4）The maximum absorption wavelength of SPEO was 441 nm by ultraviolet spectrophotometer.The single factor experiment showed that the ratio of wall to material,core to wall and p H had great influence on the embedding rate of saffron petal essential oil microcapsules（SPEO-Ms）.The optimal preparation technology for the top was as follows:the ratio of wall to material of gelatin to chitosan was 10:1,the ratio of core to wall was 1:1,and the p H was 5.4.Under these conditions,the embedding rate of SPEO-Ms could reach 65.52%.（5）Electron microscopy and environmental scanning electron microscopy showed that SPEO-Ms was a uniform sphere with smooth surface without depression and a putamen structure.The moisture content of SPEO-Ms measured by drying method was 7.3%.The infrared spectrogram（FTIR）showed that SPEO’s characteristic peak was contained in SPEO’s characteristic peak with a certain weakening,which proved that SPEO was successfully embedded in microcapsules.Thermogravimetric analysis（TG）curve shows that the microcapsule technology can improve the thermal stability of SPEO-Ms.Slow-release curve analysis showed that SPEO-Ms had a good slow-release ability.After 10 days of microcapsule placement,the retained core material still accounted for 54%of the initial core material.Microcapsule bacteriostatic test showed that microcapsule technology had little effect on the bacteriostatic ability of core materials.（6）Using waterborne polyurethane as adhesive,SPEO-Ms was adhered to cotton fiber by dipping method to prepare antibacterial cotton with essential oil microcapsules.Five groups with microcapsule concentration of 0,5,10,15 and 20 g/L were taken as test cotton fabrics.Observation by ring scanning electron microscope showed that when the microcapsule concentration reached15 g/L,microcapsules were evenly distributed on the fiber surface and still maintained uniform and smooth spheres.However,when the microcapsule concentration reached 20 g/L,the microcapsules agglomerated on the fiber surface.The gram weight,whiteness,air permeability（WAP）,moisture permeability（WVP）and antibacterial properties including different microcapsule concentrations were determined.The results were correlated with the results of loop scanning.When the microcapsule concentration reached 15 g/L,the microcapsule antibacterial cotton fabric reached the best state.The gram weight,whiteness,MAP and WVP were 1.98±0.08 g,45.33±3.33%,1262±15.6 mm s^-1and 3998.30±15.21 g m^-2day^-1,respectively.The inhibition rates of Escherichia coli,Staphylococcus aureus and Candida albicans were88.89%,90.20%and 96.13%,respectively.