Mode of Antioxidant Action of Essential Oils

There is a growing need for innovative food preservation systems. Reduction of food waste is recognised as a priority target by both FAO (2016) and the European Commission (2016). Antioxidants represent an important class of food preservatives because they are able to slow down the oxidation of unsaturated lipids (LH) contained in food, preventing therefore the development of rancidity (Schaich, 2005). Atmospheric oxygen (together with microorganisms) is the main oxidant species responsible for the decay of the organoleptic qualities of food. The reaction involved (called lipid autoxidation or peroxidation) is mediated by free radicals, which catalyse the formation of lipid hydroperoxides (LOOH) with a radical‐chain mechanism (Schaich, 2005). Butylated hydroxyanisole (BHA, E320), butylated hydroxytoluene (BHT, E321), propyl gallate (PG, E310) and tert‐butylhydroquinone (TBHQ, E319) are synthetic antioxidants commonly added to food to inhibit lipid peroxidation and the consequent rancidification. The impact of these petroleum‐derived antioxidants on human health is still under debate and generally natural alternatives are increasingly preferred (Williams et al ., 1999; Carocho et al ., 2014).