The present invention relates to water-dispersable microcapsules comprising an oil phase, e.g. a perfume, containing a photolabile α-ketoacid or α-ketoester capable of generating a gas upon exposure to light. The gas is able to cause an extension or the breaking of the microcapsule allowing the release of the oil phase and thus increasing the long-lastingness of the odor perception. The present invention concerns also the use of said microcapsules in perfumery as well as the perfuming compositions or perfumed articles comprising the invention"s microcapsules to provide a prolonged release of fragrant molecules.