These two authors contributed equally.
Unique bioactive polyphenolic profile of guava (Psidium guajava) budding leaf tea is related to plant biochemistry of budding leaves in early dawn
Version of Record online: 28 AUG 2012
© 2012 Society of Chemical Industry
Journal of the Science of Food and Agriculture
Volume 93, Issue 4, pages 944–954, 15 March 2013
How to Cite
Chang, C.-H., Hsieh, C.-L., Wang, H.-E., Peng, C.-C., Chyau, C.-C. and Peng, R. Y. (2013), Unique bioactive polyphenolic profile of guava (Psidium guajava) budding leaf tea is related to plant biochemistry of budding leaves in early dawn. J. Sci. Food Agric., 93: 944–954. doi: 10.1002/jsfa.5832
- Issue online: 18 FEB 2013
- Version of Record online: 28 AUG 2012
- Manuscript Accepted: 3 JUL 2012
- Manuscript Revised: 24 JUN 2012
- Manuscript Received: 1 MAY 2012
- National Science Council. Grant Numbers: NSC-99-2313-B-018-002-MY3, NSC-99-2320-B-038-011-MY3, NSC-100-2313-B-241-004-MY3, NSC-101-2320-B-039-040-MY3
- guava tea;
- polyphenolics and flavonoids;
- gallic acid;
- ellagic acid
BACKGROUND: Guava leaf tea (GLT), exhibiting a diversity of medicinal bioactivities, has become a popularly consumed daily beverage. To improve the product quality, a new process was recommended to the Ser-Tou Farmers' Association (SFA), who began field production in 2005. The new process comprised simplified steps: one bud–two leaves were plucked at 3:00–6:00 am, in the early dawn period, followed by withering at ambient temperature (25–28 °C), rolling at 50 °C for 50–70 min, with or without fermentation, then drying at 45–50 °C for 70–90 min, and finally sorted.
RESULTS: The product manufactured by this new process (named herein GLTSF) exhibited higher contents (in mg g−1, based on dry ethyl acetate fraction/methanolic extract) of polyphenolics (417.9 ± 12.3) and flavonoids (452.5 ± 32.3) containing a compositional profile much simpler than previously found: total quercetins (190.3 ± 9.1), total myricetin (3.3 ± 0.9), total catechins (36.4 ± 5.3), gallic acid (8.8 ± 0.6), ellagic acid (39.1 ± 6.4) and tannins (2.5 ± 9.1).
CONCLUSION: We have successfully developed a new process for manufacturing GLTSF with a unique polyphenolic profile. Such characteristic compositional distribution can be ascribed to the right harvesting hour in the early dawn and appropriate treatment process at low temperature, avoiding direct sunlight. © 2012 Society of Chemical Industry