44E-20 |
Catechin content of some commercial tea products |
Z. NAKAT1, J. E. Zimeri1, P. A. Lachance2, and E. He. (1) Dept. of Food Science/The Nutraceutical Institute, Rutgers, The State Univ. of New Jersey, 65 Dudley Rd., New Brunswick, NJ 08901, (2) Dept. of Food Science/The Nutraceuticals Institute, Rutgers, The State Univ. of New Jersey Tea (Camellia sinensis) is the most widely consumed beverage aside from water because of its attractive aroma, taste, and health-related attributes. The constituents of green and black teas have been the subject of intensive investigations due to their health attributed effects. Fresh tea leaf is unusually rich in the biologically active polyphenols known as catechins. Epigallocatechingallate (EGCG) is the largest component in the group representing 50-60% of the total catechins. Epigallocatechin (EGC), Epicatechingallate (ECG), and Epicatechin (EC) occur in decreasing amount with EGCG and ECG reported to amount to 90% of the total. Green tea beverage contains 30% catechins (wt/wt) while about 9% remain in fermented black tea. Our objective was to assess the relative concentration of two catechin biomarkers in a cross-section of commercial ready-to-drink products relative to brewed green tea (bag). Twenty-two different commercial tea beverages were tested (black and green varieties) for their EGCG and EGC content using reverse-phase high performance liquid chromatography. Our analytical findings indicate that the combined content of EGCG and ECG varies considerably. For example, green tea beverage products made in China or Japan have a higher content than American products. Therefore daily intakes would vary accordingly. The content of catechins in most commercially available brewed tea beverages was greater than that found in the ready-to-drink beverages. For a purported health benefit, the ingestion of several cups daily has been recommended. Since the NLEA label does not provide any indication of catechin content, the consumer has no way to ascertain their relative values. Therefore, labeling of bioactive or biomarker nutraceutical values would be recommended.
Session 44E, Nutraceuticals & Functional Foods
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