The Antioxidant Activities of the Some Commercial Teas

The antioxidant activities and their antioxidant compounds of a group of teas obtained in local markets were investigated. A total of 18 teas were tested for their antioxidant activities based on their ability to scavenge ABTS (2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) cation radical and DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. The former was expressed as mg of ascorbic acid equivalents per 1 tea bag (L-ascorbic acid equivalent antioxidant capacity, AEAC) and the latter was expressed as percentage of electron donating activity (EDA%). A good correlation of AEAC and EDA was observed between the two methods. The concentrations of total polyphenolics and flavonoids in tea extracts were measured by spectrophotometric methods. Total ascorbic acid was determined via the 2,6-dicholoroindophenol titrimetric method. According to the AEAC value and EDA, black tea, brown rice green tea, green tea, herb tea and malva tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of polyphenolic compounds were observed in black tea, green tea and herb tea. Overall, six teas out of 18 teas tested in the study showed better antioxidant activities and higher amounts of total polyphenolic compounds.

국내 시판되는 일부 다류 제품의 항산화 효과

본 연구에서는 일상생활에서 손쉽게 음용할 수 있는 차 추출물에 대해 항산화력과 항산화 성분의 함량을 측정함으로써 그 상관관계를 알아보고자 하였다. 차 추출물의 항산화력은 ABTS 와 DPPH radical을 사용하여 측정하였으며, 항산화력 성분은 총 폴리페놀, 총 플라보노이드, 총 비타민 C 함량을 각각 측정하였다. 총 폴리페놀 함량은 홍차, 허브티 I, 녹차 I, 허브티 II, 녹차 II, 한차 I에서 101.51~62.60 mg범위로 다른 차에 비하여 높게 나타났으며, 총 플라보노이드 함량은 허브티 II, 한차 I, 홍차에서 높은 함량을 나타내었다. 반면 총 비타민 C의 경우 한차 I이 15.78 mg을 나타낸 제품을 제외 하고 다른 것들은 모두 낮은 함량을 나타내었다. 항산화력이 높게 나타난 차는 주로 녹차류와 홍차였으며 이들의 항산화력에 기여하는 물질이 주로 비타민 C나 플라보노이드가 아닌 폴리페놀성 화합물임을 알 수 있었다.