## 4 Discussion
[17] and [PERSON] et al. [11]. In their work, [PERSON] et al. [11] refer to thefact that muscle aminopeptides do not have the same degree of preference, depending on which AA is found in the _aminus_ terminal. While alanylaminopeptides show a broad range of specificity, acting over phenylalanine, lysine, methionine, alanine and leucine, arginylaminopeptidase activity is more restricted to AA with a basic nature, like arginine and lysine [11]. The significant leucine and lysine accumulations suggest that arginylaminopeptidase seems to be the most active. Regarding ornithine, its low levels in \"RM\" samples and higher amounts at the storage end are consistent with the fact that this AA is not natural in meat proteins, its formation being attributed to microbial activity [18]. The BA formation and accumulation depend on a complex interaction of factors like the processing conditions, raw material microbiological quality and handling procedures [19; 20]. In this regard, results concerning BA are significantly impacted by the production batch. Amongst \"RM\" samples, three of them exhibited amines of bacterial origin: \(\beta\)-Phenylethylamine and cadaverine. Even in low amounts, the presence of these amines in dry-fermented sausages is indicative of the presence of bacteria with a decarboxylative capacity, which may trigger the accumulation of significant amounts of exogenous amines in later stages, as was confirmed (especially in Batch B products). As TVBN is often related to microbial development, higher levels observed also contributed to consolidate this conclusion. Despite the generalized increase in exogenous amines seen during processing, tyramine was the one that stood out in samples from Batch A. In Batch B products, tyramine levels ended up being equaled, or even surpassed, by putrescine levels. Actually, Batch B stood out with the highest total levels of BA. Such a fact is indicative of differences in terms of the existing microbiota present in each batch, particularly for those microorganisms capable of producing the enzymes involved in the production of putrescine (and cadaverine). This is the case of enterobacteria that can be found in raw material and during initial processing stages [21], whose enzymes contribute to the accumulation of putrescine and cadaverine and remain active even in the absence of viable cells during storage. The presence of tyramine in fermented products is chiefly related to LAB activity. As they are the most active bacteria participating in the fermentation process, it can be expected that this is generally the predominant amine. Similarly to other studies [22; 23; 24; 25], tyramine was the prevalent amine in samples from Batch A, associated with lower concentrations of putrescine and cadaverine. In both batches, the initial content of tyramine precursor AA was below 4 mg/100 g DM. However, while in Batch A this value increased during processing, the same was not the case in Batch B, as the tyrosine released would be immediately decarboxylated and converted to tyramine (tyramine increased more rapidly in Batch B than in Batch A). When the two processing technologies are compared, in Batch B the higher temperatures experienced by \"Control\" dry-fermented sausages seem to have favored tyrosine decarboxylase enzyme activity. In contrast, in Batch A, no differences were found due to processing technology. This discrepancy can be attributed to the strains present in the raw materials, insofar as the production of BA is dependent on the strain and not on the genus of the microorganism, as mentioned by [PERSON] et al. [26]. Finally, it is important to highlight that the ability to decarboxylate tyrosine is not exclusive to LAB. In fact, this activity has also been identified in microorganisms from the genera _Enterococcus_ and _Staphylococcus_[27]. In this sense, the accumulation of such different amounts of tyramine is admissible, even in the presence of identical LAB counts. Once BA are produced, they are very difficult to destroy by subsequent processing (pasteurization, cooking, etc.).