Heat treatments of ginger root modify but not diminish its antioxidant activity as measured with multiple free radical scavenging (MULTIS) method.

Ginger (Zingiber officinale Rosc.) root (or rhizome) has been reported to have antioxidant properties such as reactive oxygen species scavenging activities. Using multiple free-radical scavenging method, we have newly determined the scavenging abilities of ginger roots against five reactive oxygen species, i.e., HO center dot, O-2(-center dot), RO center dot, tert-BuOO center dot, and O-1(2). After heating grated ginger roots at 80 degrees C for 2 h, nearly 50% decrease in scavenging ability was recorded against O-1(2) and tert-BuOO center dot. Conversely, the O-2(-center dot) scavenging ability increased by about 56% after heat treatment. Based on the antioxidant activity measurement of the ginger's components, i.e., 6-gingerol, 6-shogaol, and zingerone, active species acting as antioxidant capacity of ginger was shown. Additionally, ginger's antioxidant capacity was quantitatively compared with that of rosemary extract, indicating that rosemary is peroxyl specific scavenger while ginger has higher scavenging ability against HO center dot and O-1(2).