• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.7-16
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• 2017

BACKGROUND: Increased value added by rapeseed (Brassica napus) by-product and the development of a usable rapeseed functional tea. METHODS AND RESULTS: To develop a usable rapeseed functional tea, the total flavonoid content in the varieties Youngsan, Tammi, Tamra, Naehan, Hanra, Mokpo No. 68, and Mokpo No. 111 was investigated. Effect of three treatments, i.e., drying, leaching, and roasting, on flavonoid contents or flower was tested using multiple processing methods per treatment. Total flavonoid content decreased under the various drying methods, confirming that flavonoid content is heat-dependent. This finding was more pronounced for freezing and oven-drying (15.3 and 13.8 mg/g DW, respectively), with a 10% difference in the total flavonoid content between the two methods. Under leaching conditions, the flavonoid content decreased with increasing treatment time. Notably, roasting methods did not result in loss of flavonoid content. The total flavonoid content in the rapeseed varieties decreased in the following order: Youngsan, Tammi, Tamra, Naehan, Hanra, Mokpo No. 68, and Mokpo No. 111. CONCLUSION: The flavonoid content in rapeseed flower was higher in Youngsan than in the other varieties, under processing conditions such as freeze-drying, leaching at $90^{\circ}C$ for 5 min, and roasting.