14E-15 |
Effect of antimicrobial activity of Omiza (Schizandra chiensis) extract on the composition and leakage of cellular material in E. coli and S. aureus |
K. H. CHUNG, Dept. of Food Science & Technology, Seoul National University of Technology, 172, Kongnung-dong, Nowon-gu, Seoul, 139-743, South Korea, S. H. Lee, and Y. C. Lee, Dept. Food Science & Technology, Chung Ang University, 72-1, Nae-ri, daedeok-myon, An seo-si, Kyeoung-gi- do, 456-756, South Korea. Conventional food preservation is being carried out by thermal processes or addition of chemical presevatives which either alter sensory and nutritional properties or causes consumer resistance. As an alternative to chemical presevatives, many researchers have looked into the antimicrobial agents from the natural sources. The antimicrobial effect of Omiza(Schizandra chinensis) extract, oriental herb, on both E. coli and S. aureus was evaluated and their anitimicrobial mechanism was also determined. The antimicrobial activity of Omiza extract on both E. coli and S. aureus was determined by quantifying the amount of cellular leakage materials, changes of lipid and amino acid as well as the cell morphology under the transmission electron microscope, which were affected by the reaction time and the amount of Omiza extract added. The amount of cellular leakage material and protein was increased with increases in reaction time and the concetration of Omiza extract in both E. coli and S. aureus suspensions. The amount of palmitic acid as a primary saturated fatty acid decreased from 28.17% to 10.85%, while that of linoleic acid as a primary unsaturated fatty acid increased from 3.93% to 56.54% in S. aureus , with similar trend shown in E. coli. However, there were no significant changes in amino acid composition in both E. coli and S. aureus . The irreglar damages of cellular surface of both strains were observed under the transmission electron microscope The mechanism of antimicrobial activity of Omiza extract can be explained by the inhibition of microbial growth which results from leaking cellular material due to the increased cell membrane permeability caused by the change of fatty acid composition.
Session 14E, Nutraceuticals & Functional Foods: General I
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