Use of oregano extract and oregano essential oil as antioxidants in functional dairy beverage formulations

To increase health benefits, dairy beverages can be enriched with omega-3 fatty acids, although these fatty acids are susceptible to oxidation. The use of oregano extract (OE) and oregano essential oil (OEO) as antioxidants in dairy beverages enriched with 2 g/100 g linseed oil was studied. The OE contained 269 mg gallic acid equivalents per gram and was shown by the DPPH radical assay to have powerful antioxidant activity. During 10 days of storage under light or heat conditions, color, conjugated diene hydroperoxides, hexanal, propanal, and dissolved oxygen concentrations were evaluated in dairy beverages containing various concentrations of OE or OEO. It was found that OE was more efficient than OEO in preventing the formation of conjugated dienes, hexanal, and propanal as well as the depletion of oxygen induced by heat or light oxidation. The addition of OE or OEO did not affect dairy beverage physical stability during storage.

► Functional foods containing omega-3 fatty acids are prone to oxidation. ► Oregano fractions were added to dairy beverages fortified with omega-3 fatty acids. ► Heat- and light-induced oxidation was significantly reduced during storage. ► Oregano water soluble extract was better anti-oxidant than oregano essential oil. ► Physical stability of dairy beverages was not affected by oregano fractions.