ABSTRACT
Any processing method that maintains the level
of compounds known for their health benefits will be of interest to the food
industries. Therefore, the effects of vacuum drying, storage and freezing on
the anthocyanin content and their antioxidant properties of Iresine herbstii L. flowers were investigated. The results showed that fresh samples (AEFF) had
the highest amount of total anthosyanin content (8.31 ± 0.23 mg/g dry matter,
expressed as cyaniding 3-glucoside equivalents), followed by 7.17 ± 0.12 mg/g
solid content, 13.72% loss of vacuum dried samples (AEDF). In comparison with
fresh samples, total anthocyanins in stored samples for two weeks at 5°C (AESF)
and frozen samples during 1 (AEZF1) and 3 months (AEZF3)
of storage were significantly (P < 0.01) reduced to 6.43 ± 0.24 mg/g solid
content, 22.63% loss, 5.65 ± 0.33 mg/g solid content, 32.01% loss and 4.71 ±
0.51 mg/g solid content, 43.33% loss, respectively. Anthocyanins from I.
herbstii L. flowers exhibited a dose-dependent (AEFF > AEDF > AESF
> AEZF1 > AEZF3, respectively) antioxidant activity
against lipid peroxidation in a linoleic acid model system as well as strong reducing power and ferrous ion
chelating abilities. Moreover, the anthocyanins extracted were found to show
remarkable scavenging activity on superoxide anion radicals, hydroxyl radicals,
hydrogen peroxide, nitric oxide radicals and deoxyribose degradation. Based on
the results obtained, we can concluded that the Iresine herbstii L.
flowers may be valuable natural antioxidant sources and are potentially
applicable in both pharmacy and food industry