An analytical technique that separates charged molecules by their migration through an electrolyte under an electric current, with cations moving toward the cathode and anions toward the anode. It is run on paper, in gels, or in capillary columns with online detection. In food science it separates proteins, enzymes and DNA fragments for identification and quality testing. SDS-PAGE resolves proteins by molecular weight, making it the standard tool for checking milk protein composition, detecting species adulteration in meat and verifying enzyme purity. Capillary electrophoresis automates the same separations with nanolitre samples and UV detection, speeding routine quality control.