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Impact of Growing Location and Harvest Time on Health Promoting Compounds from Dandelion Leafy Green
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Dandelion is considered a weed and undervalued by most people. Dandelion’s bitter sensory appeal and lack of knowledge for its health benefits offsets its potential to be consumed as a leafy green. The focus of this study investigated the impact of growing location, harvest time and determined which leafy green part acquired high levels of health promoting compounds from various dandelion varieties. Dandelion var. Catalonga leaf blade had higher amounts of vitamin C, carotenoids, chlorophyll A and chlorophyll B, antioxidant activity and dietary fiber versus the whole leaf and petiole during the late harvest. Catalonga from New Jersey had highest amounts of vitamin C, Catalonga from Texas and New Jersey contained violaxanthin, lutein, β-carotene, chlorophyll A and B. DPPH scavenging activity and total phenolic content was highest in the leaf blade of Catalonga Texas. Catalonga Texas had a higher percentage of bound bile acid salts, CDCA (sodium chenodeoxycholate) and DCA (sodium deoxycholate), and total dietary fiber. In continuation, various dandelion varieties were treated with different thermal processing techniques to acquire hot aqueous extracts and tested for antioxidant potential. Dandelion var. Garnet Stem from Texas, resulted in high DPPH scavenging activities when boiled for 15 min and microwaved for 4 min. Both boiling and microwaving contained highest antioxidant activity versus hot sonication. Lastly, successive extraction of phenolics decreased drastically as the time of boiling increased but dandelion varieties were able to recover almost at the same level of phenolics when boiled for 15 min. Results from thermal extraction presented significant amounts of antioxidant activity from Garnet Stem and was furthered investigated. Garnet Stem’s red midvein/petiole tissue was used in an optimized extraction protocol and four anthocyanins were quantified for the first time, cyanidin-3-(6-malonyl)-glucoside (A-2) with the greatest amount present. Vitamin C and β-carotene were highest in the leaf blade of Garnet Stem from New Jersey. Lutein, violaxanthin, chlorophyll a, and chlorophyll b was the highest in leaf blade of Garnet Stem from Texas. Highest bound bile acid salt was CDCA and Garnet Stem from New Jersey contained the highest amount of total dietary fiber (40.5 %). Both Catalonga and Garnet Stem varieties have different amounts of phytochemicals dependent on location and time of harvest in the leafy blade, but the presence of such health benefitting compounds proposes its use as another leafy green vegetable in the market. Dandelion leafy greens can be eaten fresh, raw or in an herbal tea form.
Gomez, Maricella Katherine (2017). Impact of Growing Location and Harvest Time on Health Promoting Compounds from Dandelion Leafy Green. Master's thesis, Texas A & M University. Available electronically from