Changes in Tasting Constituents (Tannin, Free Sugar, Total Nitrogen ) of Green Tea by Leaching Condition

침출조건에 따른 녹차의 성분(Tannin, Free Sugar, Total Nitrogen) 함량변화

Optimum leaching conditions of Korean green tea were determined by examining the relationship between sensory evaluation and tasting constituents of green tea infusion at various leaching conditions. Total nitrogen, total reducing sugar and tannin contents of green tea were $4.70{\sim}5.02%$, $16.5{\sim}18.0%$ and $10.3{\sim}12.7%$, respectively. They increased with the increased of leaching temperature and time. The sensory score was significantly correlated with the tannin contents of green tea in fusion in the range of $15{\sim}30\;mg/g$.(r=-0.9061). Optimum leaching conditions of green tea were $0.5{\sim}1.0$ min at $55^{\circ}C$, 0.5 min at $70{\sim}85^{\circ}C$ in high grade parched green tea, $1.0{\sim}2.0$ min at $55^{\circ}C$ and $0.5{\sim}1.0$ min at $70^{\circ}C$ in medium one.

적채시기별 녹차의 침출조건에 따른 유리당, 총질소 및 탄닌함량은 침출온도$(55{\sim}95^{\circ}C)$가 높을수록 침출시간(30초${\sim}$10분)이 길수록 증가하였다. 침출조건에 따른 녹차의 관능검사 결과 유리당 및 총 질소는 유의성 있는 상관관계가 나타나지 않았으나 탄닌함량과는 $15{\sim}30mg/g$의 농도에서 변곡점을 형성하는 유의성 있는 상관관계(r=-0.9061)을 나타내었다. 탄닌함량과 관능검사에 의한 녹차의 최적 침출조건은 상급차의 경우 낮은 온도$(55{\sim}75^{\circ}C)$에서 단시간 ($0.5{\sim}1$분)이었고 중급차는 $85^{\circ}C$ 이하에서 2분 이내가 최적 조건이었다.