Food Info UK lists altering pH, dehydration, irradiation, freezing, blanching, refrigeration and high pressure treatment as some of the methods typically used to prevent enzymatic browning. Other reported methods include treatment with supercritical carbon dioxide, ultrafiltration and ultrasonication.
Supercritical carbon dioxide describes liquid carbon dioxide at high pressure. According to Wikipedia, the fluid is typically used to kill microorganisms that cause enzymatic browning. However, the liquid can also be used to inactivate certain types of enzymes, such as those found in potatoes, shrimps and lobsters. Ultrasonication is also used to prevent to prevent enzymatic browning, but it functions on a smaller scale. The method uses high-frequency sound waves to liberate highly reactive radicals from water that then destroy molecules that cause browning. Ultrafiltration relies on membranes to separate liquid components according to size and structure. Enzymatic browning can also be prevented by using enzyme inhibitors. There are several types of inhibitors. Reducing agents such as ascorbic acid and cysteine remove oxygen. Chelating agents such as phosphates and organic acids leach out metal compounds. Acidulants such as phosphoric acid and citric acid work by lowering the pH. Wikipedia explains that enzyme inhibitors such as peptides deactivate browning enzymes by reacting with them. The University of Florida's Office of Technology Licensing has also reported success with compounds derived from mussel extracts.