A hydrodynamic cavitation method for degumming triglyceride oil is used to increase oil yield and reduce impurities. The residence time of the oil for degumming in the cavitation field is reduced to enhance removal of impurities such as phosphorus without prolonged exposure of the oil to cavitation conditions. The mass transfer of impurities from an oil phase to non-oil components or water is carried out in a non-cavitational, mass transfer reactor positioned downstream of a hydrodynamic cavitation device. A separation step can be used to remove the phosphatides and other impurities from the treated oil to form a purified oil product.