18C-13 |
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J.-Y. LEE1, J.-H. Baik2, J.-C. Roh1, and S.-K. Park1. (1) Dept. of Food Science and Biotechnology, Kyung Hee Univ., Yongin-Si, 449-701, South Korea, (2) R & D Center, Amore Pacific Corporation, Yongin-Si, 449-729, South Korea Green tea consumption has been growing rapidly worldwide primarily due to the health benefits of the green tea drinking. Unlike other beverages, green tea aroma is characterized as weak and subtle. Therefore, analysis of green tea aroma requires special techniques that should extract the aroma compounds from the tea sufficient for the analysis without artifact formation. We have developed a rapid and reliable method for the analysis of free and glycosidically bound aroma compounds in green teas. This method employed the solid phase microextraction (SPME) for the free, and enzyme hydrolysis of the bound aroma followed by SPME adsorption for the bound analysis. Various conditions for the optimum results were investigated. For the free compounds, the highest volatility of the compounds was obtained when the sample solution pH was in acidic condition (pH 3), in which the enzyme also showed high in its activity. For the bound compounds, the glycosides were directly hydrolyzed by the enzyme with b-glycosidase activity and the released aroma compounds were subsequently adsorbed onto the SPME fiber for the GC analysis. The effect of temperature on activity of the b-glycosidase was measured by varying incubation temperature from 30oC to 80oC at intervals of 10oC. It was activated at 55oC to 70oC at least 80% maximum activity. The method showed high reproducibility (RSD, 3.53%), no-artifact formation, and have several other advantages over previous methods for green tea aroma analysis.
Session 18C, Food Chemistry: Food composition, analysis and volatiles
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |