Mayonnaise was supplemented with vegetables (5 % w/w) and the effect of storage time at 4 °C on the oxidative stability of the dispersed phase was investigated. Results indicated that mayonnaise is prone to lipid oxidation during storage under refrigerator conditions. The type of vegetable used for mayonnaise reformulation was critical in inhibiting oxidation and followed the order beetroot > carrot ≈ onion with respect to antioxidant capacity. Broccoli induced a pro-oxidant effect and the rate of oxidation by the end of the storage period was 42 times higher compared with the control. The addition of beetroot, either fresh or freeze-dried, improved the oxidative stability of mayonnaise significantly. The process of freeze-drying affected adversely the ability of vegetables to decrease oil oxidation of the emulsions. This may reflect loss of important natural antioxidants during the drying procedure.
Bibliographical noteAcknowledgments This work is part of the Strategic Research 2011–2016 and is funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS).