Effects of Light Quality and Environmental Temperature on the Anthocyanin and Rutin Contents, and DPPH Radical-scavenging Activity of Buckwheat Sprouts

Abstract

  The effects of light quality and environmental temperature on both the anthocyanin and rutin contents, and on the DPPH radical-scavenging activity of buckwheat (Fagopyrum esculentum Moench) sprouts were examined. Buckwheat sprouts were grown a length of 12 cm in darkness at 15, 25, and 35 ℃ . The sprouts were then irradiated with white (three-band fluorescent), blue, UV-A, and UV-B light for 24 hours at 15, 25, and 35℃, and compared with the sprouts grown in darkness. The results show that the highest levels of anthocyanin and rutin, and the highest radicalscavenging activity were found in the seedlings grown at 25℃ in UV-B light. The seedlings grown at 15℃ in UV-B light also exhibited increased contents of anthocyanin and rutin, and greater radical-scavenging activity than the sprouts grown in darkness, although the increases were smaller than in the sprouts grown at 25℃ . The UV-B light treatment at 35℃ increased the anthocyanin content but had no effect on the rutin content nor on the radical-scavenging ability. The optimal temperature of 25℃ with UV-B irradiation proved best for increasing the flavonoid production and radical-scavenging activity of this species.