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Nutrients, polyphenols, and total antioxidant activities in Mamaki, Pipturus albidus
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|Title:||Nutrients, polyphenols, and total antioxidant activities in Mamaki, Pipturus albidus|
|Keywords:||Pipturus albidus -- Hawaii|
|Abstract:||Mamaki, Pipturus albidus, is currently one of the only native Hawaiian plants suitable for use in herbal tea preparation. This study includes determination of the nutritional values in dried Mamaki leaves and teas, mineral solubilities, and mineral comparison between those in Mamaki and other commercial tea products. Five varieties, "hybrid purple", "green", "purple sub-variety 1", ''purple sub-variety 2", and ''panaewa'', of Mamaki were harvested in winter and summer. The nutrient composition of dried Mamaki leaves and teas were analyzed using AOAC methods. Statistical analysis for dried Mamaki showed that macronutrient values, such as protein, fat, neutral and acid detergent fibers, lignin and cellulose, in summer were significantly different from those in winter. The mineral values, such as phosphorus, magnesium, boron, iron, manganese, molybdenum, and zinc, were also significantly different between the two seasons. No significant nutrient differences among the varieties of Mamaki leaves were found. Statistical analysis for Mamaki teas showed that potassium, magnesium, boron, iron, and manganese level in summer were significantly different from those in winter. There were no significant nutrient differences among the varieties of Mamaki teas. Sodium (22.1%) was the most soluble mineral while iron and manganese (0.1%) were both the least soluble minerals in infusion of Mamaki leaves to teas. Mamaki leaves contained high amounts of potassium, calcium, magnesium, zinc, iron, and copper in 5 comparison to those in other commercial tea leaves. Mamaki teas contained high amounts of calcium, magnesium and sodium in comparison to those available in other commercial teas.
Three phenolic acids in Mamaki leaves were identified and quantified using the LCMS method. (+)Catechins, chlorogenic acid, and rutin were identified at 1. 20.7 min, 23.0 min, and 55.6 min respectively. Concentrations of (+) catechins, chlorogenic acid, and rutin in a gram of Mamaki extract vary from 1.1 mg to 5.0 mg. The concentration of(+) catechins in Mamaki leaves was higher than those in Gyokuro green tea leaf, Chinese oolong tea leaf, and Kenya black tea leaf. The concentration of rutin in Mamaki leaves was about the same as those in Kenya black tea leaves but much higher than those in Gyokuro green tea leaves and Chinese oolong tea leaves This study also quantified total antioxidants using the photochemiluminescence (PCL) method and was measured in equivalents to ascorbic acid (AA). Mamaki teas brewed for thirty minutes contained total antioxidant activity (TAA) ranges from 238 mg AA/gram of tea to 259 mg AA/gram of tea. Mamaki teas brewed for one hour and stored at 4 hours, 1 day, 3 days, and 6 days at 4°C had available TAA 293,271,172,163, and 262 mg AA/g of tea, respectively. Mamaki teas contained relatively low amounts of TAA compared to green teas and Lipton teas.
|Description:||Thesis (M.S.)--University of Hawaii at Manoa, 2006.|
Includes bibliographical references (leaves 38-41).
vii, 45 leaves, bound ill. (some col.) 29 cm
|Rights:||All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.|
|Appears in Collections:||
M.S. - Food Science|
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