Identification of proteolytic products as indicators of quality in ground and whole meat

This study was devoted to the identification of specific peptides and proteins which can serve as indicators of spoilage in meat. Samples of ground and whole meat were subjected to storage at 4C; at intervals of 0, 2, 4, 8, 12 and 16 days, samples were analyzed for pH and microbial populations and subjected to extraction and separation of individual sarcoplasmic and myofibrillar peptides and proteins by SDS (sodium dodecyl sulfate) and native electrophoresis and by RP-HPLC. Sarcoplasmic protein and peptide fractions from RP-HPLC were collected and identified by (electrospray ionization mass spectrometry) ESI-MS. The results demonstrated substantial differences in microbial population and pH between ground and whole meat during storage. Separation by SDS-electrophoresis showed substantial changes in myofibrillar protein of ground meat after 12 days and of whole meat after 16 days of storage. Separation and identification of sarcoplasmic proteins by SDS-electrophoresis and by RP-HPLC followed by ESI-MS revealed the disappearance of a protein fraction band of MW 36 kDa after 8 days of storage in ground and whole meat.