Proteases in fish and shellfish: Role on muscle softening and prevention

Textural quality of fish and shellfish is the most important factor because it limits consumer acceptance as well as market price. The muscle softening or mushiness of fish and shellfish during storage or distribution in ice is generally occurred. This phenomenon is considered as the muscle protein degradation due to the proteolytic activity. The presence of active proteases in muscle and digestive organ makes the flesh fish and shellfish prone to degrade especially during iced storage, since the digestive organ is not practically removed prior to storage. The digestive tracts have been known to have high proteolytic or collagenolytic enzymes. During storage of fish and shellfish, the intensive hydrolysis of myofibrillar and collagenous proteins by proteases can be observed. To lower the muscle degradation, different pre-treatment methods as well as protease inhibitors have been applied in the stored fish and shellfish. Thus, the knowledge gained can be then transferred to the seafood processors for the quality improvement of fish and shellfish, especially those with iced storage, leading to a full market value of fish species.