oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen violaxanthin oxygenase activity molecular_function Catalysis of the reaction: violaxanthin + 2 O2 = 2 5,6-epoxy-3-hydroxy-9-apo-beta-caroten-9-one + 4,9-dimethyldodeca-2,4,6,8,10-pentaenedial. MetaCyc:RXN-7886 GO:0102785