Meat Protein Degradation by Tissue and Lactic Acid Bacteria Enzymes

During the fermentation and ripening of dry fermented sausage, a large number of biological reactions occur in the sausage mince. Proteolysis is considered to be one of the major processes involved in texture and flavor development. Moreover, small peptides and free amino acids, thus originated, are essential constituents of the nonvolatile compounds with flavor properties (1 ). Free amino acids are also the origin of other aroma volatile compounds that are involved in further enzymatic and chemical reactions (2 ,2 ). This is the result of the proteolytic activity of both endogenous and microbial enzymes. In recent years, the proteolytic system of lactobacilli involved in meat fermentation is becoming the focus of an increasing number of studies because of the technological roles of these organisms (5 –7 ). The study of the enzymology of dry fermented sausages is quite complex because of the coexistence of endogenous and microbial enzymes, which prevent the determination of the independent contribution of each enzymatic system in the whole proteolytic event. For this reason, it was necesary to establish aseptic conditions to evaluate the real function of endogenous enzymes and lactic acid bacteria (LAB).