Antioxidant and Whitening Effects of Dahlia based on Variety, Flowering Form, Harvest Time, and Plant Part

Abstract

Purpose: This study evaluated the antioxidant activity of dahlias based on variety, flowering form, harvest time, and plant parts, analyzed the content of bioactive compounds, and assessed the whitening effect of different plant parts to explore potential applications in the food, pharmaceutical, and cosmetic industries.Methods: Antioxidant activity was assessed using DPPH radical scavenging assays, whereas bioactive compounds were quantified through total polyphenol content (TPC) and total flavonoid content (TFC) measurements. The whitening effect was evaluated based on tyrosinase inhibition rates.Results: Among the six dahlia varieties examined, <i>D. diva</i> demonstrated the highest antioxidant activity, with purple and deep red varieties, showing particularly high levels of activity and polyphenol content. Analysis of flowering forms indicated that flowers in the early half-blooming stage exhibited the highest antioxidant activity. Regarding harvest time, dahlias harvested during the third period in the fall, showed the greatest antioxidant activity. Examination of different plant parts revealed that petals had the highest antioxidant activity, whereas leaves and tubers had comparatively lower activity. Additionally, petals exhibited the highest tyrosinase inhibition rate among the plant parts, although the overall whitening effect was minimal.Conclusion: The study identified the optimal dahlia variety, flowering form, harvest time, and plant parts for maximizing antioxidant effects. These findings provide valuable insights for potential applications of dahlias in various industries.