Marine shellfish proteins represent valuable marine bioresources whose functional and nutritional properties can be significantly enhanced through physical and biological processing. Physical methods primarily modify protein structure and particle size to enhance functionality, whereas biological approaches employ enzymatic hydrolysis to improve bioactivity and bioavailability. These processing methods provide a broader scope for the application of shellfish proteins in the food industry. Such modifications result from changes in protein particle size, solubility, emulsion stability, secondary structure, and bioactivity. Physical treatments induce phenomena including friction, collision, shear forces, turbulence, and cavitation, which alter protein particle size. Studies demonstrate that processing methods such as ultrasound, high-pressure homogenization, ball milling, and enzymatic hydrolysis modify the structural, physical, and chemical properties of food-derived proteins.