Abstract:

The essential oils of emblica fruit were extracted by means of supercritical CO₂ extraction (SFE) , and the antimicrobial activity of the product was investigated by using the agar dilution technique , with potassium sorbate as the control. Then , GC-MS was adopted to identify the composition of the product. The results show that ( 1) the extracted oils have a high antimicrobial activity against the original contaminating bacteria such as Bαcillus
subtilis , Stαphylococcus aureus， Escherichia coli , Salmonella , Saccgaromyces cerevisiae and Aspergillus oryzae; (2) Bacillus subtilis , Staphylococcus aureus ， Salmonella， Saccgaromyces cerevisiae , Aspergillus oryzae and Aspergillus niger are more sensitive to the oils extracted at 20 MPa than to potassium sorbate; (3) there are thirty compounds in the oils extracted at 20 MPa , mainly including β-bourbonene (38. 23%)， hexacosane (17. 2% ), thymol (10.94% ) , pentacosane (8.51 % ) ，β-carγophyllene (5.39%)， 2 , 3-dihydroxypropanol (4.36%) , palmitic acid (2.65%) and methyl eugenol (1.25%) ; and (4) the antimicrobial activity of the oils mainly results from the existence of methyl eugenol ，β-caryophyllene ，β-bourbonene and thymol.

Key words: Phyllanthus emblica, essential oil, supercritical CO₂ extraction, composition, antimicrobial activity