Enrichment under stirring at room temperature or above this
level was found to result in efficient transfer of the antioxidants
to VOO, whereas simply placing the herbs into contact with the
oil was not. The antioxidant rosmarinic acid was detected in all
herb-treated samples; on the other hand, caffeic acid, which is
present in thyme, was detected in none. Oregano was the herb
leading to the greatest enrichment of VOO with rosmarinic acid;
in fact, it reached concentrations of up to 5 mg L1 under stirring
at room temperature and up to 10 mg L1 at higher temperatures
(35–40 C).