POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT
Location: Tropical Crop and Commodity Protection Research
Title: Major phenolic acids and total antioxidant activity in mamaki leaves, Pipturus albidus
| Kartika, H. - UNIV HAWAII |
| Li, Q.X. - UNIV HAWAII |
| Nakamoto, S.T. - UNIV HAWAII |
| Iwaoka, W.T. - UNIV HAWAII |
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 5, 2007
Publication Date: November 26, 2007
Citation: Kartika, H., Q.X. Li, M.M. Wall, S.T. Nakamoto, and W.T. Iwaoka. 2007. Major phenolic acids and total antioxidant activity in mamaki leaves, Pipturus albidus. Journal Food Science 72:S696-S701.
Interpretive Summary: Mamaki is a medicinal plant used by native Hawaiians for therapeutic purposes. Plant phenolics are potent antioxidants and may contribute to the medicinal value of mamaki. Three major polyphenols were identified in mamaki leaves, and the antioxidant activity of mamaki teas were measured. Mamaki teas had similar amounts of total antioxidant activity as green, oolong, or black teas.
Three phenolic acids, (+) catechins, chlorogenic acid, and rutin, were identified and quantified in mamaki leaves (Pipturus albidus) using a liquid chromatograph-mass spectrometer technique. Concentrations of (+) catechins, chlorogenic acid, and rutin varied from 1.1 mg to 5.0 mg per gram of mamaki leaves as determined in the extract using 0.5% acetic acid in 90% aqueous methanol. This study also quantified total antioxidant capacity using the photochemiluminescence method, which was expressed in equivalents to ascorbic acid (AA). Mamaki teas brewed for thirty min contained total antioxidant activity (TAA) between 238 and 259 mg AA/gram of tea. Mamaki teas brewed for one hour and stored at 4 hours, 1 day, and 3 days at 4ºC had available TAA of 293, 271, 172, and 163 mg AA/g of tea leaves, respectively. The concentration of (+) catechins and rutin in mamaki leaves are compared to other types of popular teas. Mamaki teas had similar amounts of TAA compared to green, oolong, or black teas.