Actin proteolysis during ripening of dry fermented sausages at different pH values

In dry fermented sausages, myofibrillar proteins undergo intense proteolysis generating small peptides
and free amino acids that play a role in flavour generation. This study aimed to identify small peptides
arising from actin proteolysis, as influenced by the type of processing. Two acidification profiles were
imposed, in order to mimic the pH normally obtained in southern-type and northern-type dry fermented
sausages. The identification of peptides was done by liquid chromatography coupled to mass spectrometry
in a data-independent positive mode of acquisition (LC-MSE). During manufacturing of the dry fermented
sausages, actin was highly proteolysed, especially in nine regions of the sequence. After
fermentation, 52 and 42 actin-derived peptides were identified at high and low pH, respectively, which
further increased to 66 and 144 peptides, respectively, at the end of ripening. Most peptides were
released at the cleavage sites of cathepsins B and D, which thus play an important role.