• FLOWER RESEARCH JOURNAL
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• v.26 no.4
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• pp.202-208
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• 2018

This experiment was conducted to determine optimal hot-air drying time for producing antioxidative calendula tea. The edible calendula was dried in hot air at $60^{\circ}C$ for 5, 10, 15 hours and Hunter's color value was measured and extracted with 95% ethanol as a solvent. The contents of total polyphenol, total flavonoid, total carotenoid and DPPH (2,2 Dipheny-1-picrylhydrazyl) radical scavenging activity were investigated. The correlation between the amount of antioxidant and antioxidant activity was analyzed. As the treatment time increased, the Hunter values of L, a, and b tended to decrease, and the L value and b value decreased significantly at 15 hours. The color change was occurred in all treatments compared with the control, and the total color difference (${\Delta}E$) was the largest at 15 hours treatment. The contents of total flavonoids, total carotenoids and DPPH scavenging activity increased in the 5 hours, but decreased in the 15 hours compared to the 10 hours. The content of total polyphenol was not changed with different treatment time. A positive correlation ($p{\leq}0.01$, r = 0.610) between carotenoids and DPPH radical scavenging activity was demonstrated. The DPPH radical scavenging activity was increased at 5 and 10 hours compared to the control and decreased at 15 hours. Therefore, 5 hours or 10 hours of treatment is appropriate and further studies are needed to determine the specific treatment time.