녹차엽의 채취 시기와 재배지역에 따른 휘발성 향기 성분의 변화

Changes in Volatile Compounds of Green Tea during Growing Season at Different Culture Areas

  • 이주연 (경희대학교 식품생명공학과) ;
  • 왕려비 (태평양기술연구원) ;
  • 백주현 (태평양기술연구원) ;
  • 박승국 (경희대학교 식품생명공학과)
  • 발행 : 2007.06.30

초록

본 연구에서는 녹차엽의 채취 시기와 재배지역에 따른 휘발성 향기성분의 종류, 차이, 그리고 변화를 비교하기 위하여 제주와 전남지역에서 재배한 차의 생엽을 시기별로 채취하였다. 녹차엽의 휘발성 향기 성분은 SPME를 사용하여 포집, 흡착하여 GC, GC-MS, GC-O, 그리고 retention time을 이용하여 분리된 성분을 분석, 동정하였다. 녹차엽의 휘발성분의 양은 수분함량을 고려한 건조함량을 기준으로 정량하였다. 수분함량은 생엽이 78-80%, 건조엽이 3.20-4.98% 정도였다. 휘발성 향기성분의 흡착에 사용되는 SPME 방법은 이전의 여러 방법에 비해 분석시간이 짧고 본래의 향이 아닌 방해성분의 생성이 적은 장점이 있다. 본 연구에서 사용한 SPME fiber는 7.4%의 높은 재현성을 가졌으며 표준물질(ethyl n-heptanoate)의 내부표준법에 의한 재현성 결과에서는 불안정한 peak area값(RSD 30.5-98.7%)을 가져 3.47%의 재현성 결과를 가진 외부표준법을 사용하였다. 시기에 따른 휘발성 향기 성분을 비교한 결과, 5월에 채취한 생엽의 휘발량이 가장 많았으며, Group I과 Group II 향기특성의 함량비율이 균형적이었다. 휘발량이 가장 많았던 5월에 채취한 생엽을 제주와 전남의 재배지역으로 구분하여 비교한 결과, 주 성분은 Z-3-hexenal, linalool, E-2-hexenol, n-hexanal, Z-linalool oxide, myrcene, benzyl alcohol이었다. 이러한 결과는 채엽 시기가 녹차의 향기 특성에 영향을 주며, 채엽 시기가 같더라도 지역에 따라 향기가 다른 녹차가 제조될 수 있다는 것을 나타낸다. 본 연구는 녹차를 지역에 따라 구분하는 데에도 도움이 될 것으로 예상된다.

Fresh tea leaves grown in Jeju Island and Jeonnam Province of South Korea were plucked and processed. Volatile compounds (VCs) were analyzed and identified with SPME-GC/GC-MS/GC-O. The VCs of green teas were classified into two major categories based on their aroma characteristics: the Greenish (Group I), and Floral (Group II) odorants. It was found that the VCs were decreased significantly in fresh tea leaves as they were plucked at the later stages of cultivation. The ratio of VCs responsible for Group I and Group II compounds was well-balanced in tea leaves plucked in May, but the balances were changed when the fresh leaves were processed. The major VCs of fresh tea leaves in Jeju and Jeonnam were n-hexanal, E-2-hexenal, Z-3-hexenal, myrcene, benzyl alcohol, linalool, and phenyl alcohol. Also, Jeju and Jeonnam tea leaves had different aroma composition. n-Heptanol, ${\beta}-pinene$, benzaldehyde, and ethyl salicylate were found in Jeju fresh tea leaves, and Z-3-hexenol, E-2-hexenol, and methyl n-heptanoate were detected in Jeju dry tea leaves. On the other hand, Z-linalool oxide and myrcene were found in Jeonnam dry tea leaves. The SPME-GC method showed high reproducibility (RSD, 7.4%) with no-artifact formation. In this study, optimum plucking period of tea leaves could be determined for production of high quality green tea with a well-balanced aroma and characteristic VCs in green tea according to growing areas.

키워드

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