Processes and systems are provided for effectively degumming vegetable oils with the use of an acid and base pretreated mixture of vegetable oil. The pretreated mixture is subjected to compression and one or more intervals of explosive decompression of the compressed mixture to form a degummed vegetable oil. Also provided are compression and decompression rates and conditions that can be used to effectively degum vegetable oil to achieve reduced levels of phosphorus and metals such as iron, calcium and magnesium.