Oxygen consumption is characteristic of the propagation
phase and the effect of the antioxidants on the
progress of lipid oxidation, during which peroxyl radicals
are chain-carrying, is directly measured in the assay
of the rate of depletion of oxygen in a peroxidating lipid
emulsion. The plant extracts explored in the present
study showed different effects on the oxygen depletion
in the assay, based on metmyoglobin-initiated oxidation
of methyl linoleate. As may be seen from Table 2, the
antioxidative indices of LRK, LR and other selected
antioxidants showed different concentration dependencies.
Notably, LRK is most effective in halting the oxygen
consumption by the peroxidating lipid emulsion and
comparable to the effective chain-braking antioxidant
Trolox. LR is the second least effective and only more
effective than ascorbic acid, which is not normally considered
effective in such O/W-emulsions, although the
concentration effects of the antioxidants are different.
The green tea polyphenols (GTP) are comparable,
although not quite as efficient as LRK. The overall
ranking for the five plant extracts and the two watersoluble
antioxidants is accordingly, when correction for