Skeletal muscle fiber type and myofibrillar proteins in relation to meat quality.

Although numerous studies have reported the relationships among muscle fiber characteristics, lean meat content and meat quality, controversial perspectives still remain. Conventional histochemical classifications may be involved in a high level of error, subjectivity and it could not clearly explain variety of myofibrillar protein isoforms. Therefore, more information is needed on how different factors, such as species, breeds, gender, nutrient conditions, physiological state of animals, and environment factors, affect ultimate meat quality in order to evaluate these uncertainness. Unfortunately, there is little information that completely covers with relationship among the muscle fiber types, myofibrillar proteins and enzymatic proteolysis. In addition to the perspective of postmortem metabolism, protein quality control in skeletal muscle and proteolytic degradation of muscle proteins during postmortem period could help to clarify this relationship. Therefore, the present review will focus on muscle fiber types, typing methods, muscle proteins and meat quality, and will summarize aspects of enzymatic view of proteasome.