An enzyme that has been chemically or genetically altered to change its activity, stability, or specificity. Food technologists modify enzymes to survive harsh processing conditions, work at new pH or temperature ranges, or produce different reaction products. Techniques include chemical cross-linking, immobilisation on solid supports for reuse, and protein engineering that redesigns the enzyme’s structure. Modified enzymes improve cheese ripening, clarify juices, enhance baking, and produce lactose-free milk more efficiently. Because they are processing aids rather than ingredients, they often do not appear on labels, though their safety must be established. Enzyme modification exemplifies the precision now possible in food biotechnology.