| Xiangyuan {Citrus Wilsonii Tanaka)with its attractive and pleasant flavor characteristics was anylisised by extraction techniques,GC-MS analysis technology,microencapsulation technology to do the high-tech research and its application products to achieve efficient use of resources for xiangyuan.1.The extraction conditions(material fliuid ratio,Extraction time and concentration of NaCl)of hydrothermal method were discussed based on the single factor experiment combined with orthogonal desicgn.The results indicated the optimum extracting condition of hydrothermal method:solid/liquid ratio,1:2;Extraction time,3 hours;concentration of NaCIL 3%;at this condition the extraction ratio reached 1.59%.2.The composition of the essential oil of Citrus wilsonii Tanaka(Xiangyuan)isolated by the hydrothermal method,was investigated by GC-MS-O.A total of 44 volatile constituents were confirmed in the Xiangyuan essential oils.Forty-four compounds were identified in the oil.Along them,monoterpenes hydrocarbon reaches the highest content of 90.59%.Limonene(50.53%)was the major component,followed by p-ocymene(16.40%),?-Terpinene(8.75%),?-ocimene(5.03%),?-Pinene(3.35%),?-Pinene(2.66%),and ?-Myrcene(2.30%).Eleven aroma-active constituents were investigated by capillary GC-MS-O.Nine compounds,?-Pinene,?-pinene,p-ocymene,limonene-oxide,linalool,4-terpinenol,trans-p-Mentha-2,8-dien-l-ol,neryl acetate,and valencene were indentified.From the sniffing results,p-ocymene and terpinyl propionate were suggested as key contributors to the characteristic aroma of xiangyuan oil.3.The antioxidant activities of xiangyuan essential oil were evaluated based on the method of vitro antioxidant and agar diffusion.The results for the antioxidant capacity of xiangyuan essential oil increases with the increasing concentration,there is scavenging activity on DPPH free radicals,·OH free radicals(IC50=0.32 mg/mL and H2O2(IC50?148 ?g/mL).The antimicrobial activity and its stability of the essential oils against five species of microorganisms(Escherichia coli,Staphylococcus aureus,Bacillus subtilis,Saccharomyces cerevisiae,Aspergillus niger)were discussed by the disc diffusion method.The essential oils showed inhibition zones against all microorganisms tested.The data indicated that Aspergillus niger was the most sensitive microorganism tested,with the largest inhibition zone(25.39± 1.12 mm),and Staphylococcus aureus exhibited the smallest inhibition zone(14.04±1.35 mm).Minimum inhibitory concentrations(MICs)ranges from 0.31mg/mL-1.25mg/mL.At the certain range of pH(3-8),temperature(80?,115?,121 ?)and UV(20min,40min,60min)impact compared with the control,xiangyuan essential oil remained relatively stable antimicrobial properties.Xiangyuan essential oil displayed a broad antimicrobial spectrum and exerted a strong antimicrobial effect against five strains tested.4.The preparation conditions(concentration of ?-cyclodextrin,entrapped temperature,entrapped time)of microencapsulation method were discussed based on the single factor experiment combined with orthogonal design.The results indicated the optimum extracting condition of hydrothermal method concentration of?-cyclodextrin,2 mmol/L,entrapped temperature.65 ?;entrapped time.4h;at this condition the encapsulation ration reached 70.5%.Compared the microcapsules of essential oils added into xiangyuan fruit juice with xiangyuan simulation juice,there is significant difference between the aroma characteristics of the two samples by sensory evaluation.SPME-GC-MS analysis results showed that both the volatile component composition similar to the analog high juice acceptance.In summary,xiangyuan essential oil is rich in a variety of flavor compisition,and has a strong antimicrobial and antioxidant capacity,the prepared microcapsules also have better performance.There are quite good prospects on the applications of xiangyuan essential oil. |
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