## 4 Discussion
Moreover, the use of sodium ascorbate in combination with whey resulted in the lowest peptide content. However, the antioxidant activity of peptides was independent of their content because the sample with the lowest peptide content (with acid whey and sodium ascorbate) showed the highest antioxidant activity, significantly higher compared to the cured sausage sample. Moreover, the antioxidant activity of peptides isolated from dry fermented sausage with acid whey addition (SAW) did not differ significantly from the sausage sample produced with acid whey and sodium ascorbate. As shown by available scientific research, molecular weights and the amino acid sequence play a vital role in determining the antioxidant activity of the peptides [37]. According to previous reports on peptides derived from other sources [38; 39; 40], smaller molecular weights of crude peptides tend to have higher antioxidant activity. Specific amino acid sequences of peptides are also important for their properties [41]. The amino sequence of Pro-His-His exhibited higher antioxidant capacity in the linoleic acid system than that of other synthetic peptides. Similarly, tripeptides with Trp and Tyr residue at the C-terminus could exert strong radical scavenging activities. Moreover, it was indicated that more than half of the peptide sequences derived from animal proteins with strong scavenging radical capacity contain hydrophobic amino acids. The antioxidant properties of peptides are crucial for meat products' quality, as oxidative changes related to protein and lipids take place during the production of dry fermented sausages. These properties help to improve the shelf life of the products [42; 43]. In the present study, TBARS was used to evaluate the degree of lipid oxidation of fermented sausages. As expected, acid whey and sodium ascorbate's combined addition resulted in significantly decreasing the level of secondary products of lipid oxidation. It has been shown that the application of ascorbate salt in meat products inhibits lipid oxidation [21; 43] as this compound is involved in redox reactions. Ascorbate acts as an electron donor, and its oxidized form (dehydroascorbic acid) is relatively uncreative and therefore terminates the propagation of free radical reaction. Its ability to react with iron ions and thus elimination of the negative catalytic effect of iron ions is also known [21]. The protective properties of the additives used (acid whey in combination with sodium ascorbate) were also observed in the content of heme pigments and heme iron on the 14 th day of production. During the storage and processing of meat, hemin could dissociate from the globin, and heme oxygenase and reactive oxygen species could cause heme destruction, which subsequently releases iron from the heme ring [44]. The consequence of this phenomenon is the reduction of heme iron and the formation of a form of \"free\" iron. This situation has been observed in current research during the production of raw fermented sausages. The sodium ascorbate used inhibited the destructive processes of myoglobin only until the 14 th day of production. On the 21 st day of production, all samples were characterized by a similar content of heme iron. Fermented meat products are one of the most common dietary sources of biogenic amines (BAs). Although BAs can be found in a wide range of meat products; during fermented meat products production, especially suitable environmental conditions take place that favor the accumulation of these compounds due to the activity of microorganisms showing decarboxylase enzymes activity [21; 45]. In this context, they are important as an index for product quality, but also for their impact on public health [44]. The most common BAs occurring in fermented foods are tyramine, putrescine and cadaverine [46; 47]. In the current study, in addition to the indicated amines, small amounts of spermine were also detected.