Quantification of fresh meat peptides by SDS-PAGE in relation to ageing time and taste intensity

The extraction and quantification of fresh meat peptides in the molecular weight (MW) range between 3 and 17 kDalton (kDa) was examined, as well as their evolution during post-mortem ageing and their relation to taste intensity. Using a Tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) method, quantification of fresh meat peptides in this MW range was possible. Correlation coefficients higher than 0.98 were found between the absolute amounts of peptides loaded on the gel and the measured amounts expressed as cytochrome c equivalents. In contrast to the extraction in the presence of SDS, extraction with 0.1 N HCl, 3% HClO(4) and 0.9% NaCl only partially recovered peptides present in fresh meat samples in both the 3-10 and 10-17 kDa MW range. A substantial increase in peptide concentration in the 3-17 kDa MW range with time post-mortem in both pork and beef fresh muscle samples was found. For grilled beef longissimus lumborum and semimembranosus samples of different origin and ripening times, both the concentration of the peptides in the 3-10 kDa MW range and the intramuscular fat content were significantly related with taste panel intensity scores, while the correlation with the amount of peptides in the 10-17 kDa MW range was not significant.