Effects of thermal treatment on radical-scavenging activity of single and mixed polyphenolic compounds

Rutin, luteolin, luteolin-7-glucoside, and chlorogenic acid gradually decomposed during heating at 100 degreesC. Even though they rapidly decomposed at 180 degreesC, some decomposition products still had radical-scavenging activity. When rutin was heated in the presence of chlorogenic acid, decomposition of rutin was almost totally inhibited at 100 degreesC, but was reduced at 180 degreesC. These results suggest that the radical-scavenging activity is more stable than the content of original polyphenolic compounds in foods during cooking and processing.