# Antimicrobial and Antioxidant Properties of Bovine Livers and Hearts Hydrolysates
###### Abstract  
Our previous research has indicated that bioactive protein hydrolyses derived from porcine by-products possess the potential to be utilized in the production of functional additives and food supplements. The objective of this investigation was to assess the antioxidant and antimicrobial characteristics and amino acid changes in hydrolyses of lyophilized meat of bovine livers and hearts. The relevant enzymes, papain and pepsin, were used to hydrolyze the meat by-products over periods of 3, 6, and 24 h. The antimicrobial properties of all enzymatically digested samples were assessed against _Listeria monocytogenes_, _Bacillus cereus_, _Salmondella enterica_ subsp. _enterica_ Serovar Typhimuriumium. _Bacillus cereus_, and _Escherichia coli_, _S. aureus_ subsp. _aureus_. The assessment of antiradical activity involved the quantification of DPPH\(\bullet\) and ABTS\(\bullet\)+ absorbance in bovine by-product hydrolyses. The hydrolyses were subjected to amino acid analysis using AccQ Tag technology, which was performed by Waters Corporation in Milford, MA, USA. The bacteria _L. monocytogenes_ had the highest antibacterial activity (inhibition zone) (20.00 \(\pm\) 0.20 mm) and less against _E. coli_ (10.00 \(\pm\) 0.10 mm) of bovine heart hydrolyses and were prepared for 24 h with papain. The highest values of ABTS\(\bullet\)+ (98.1 \(\pm\) 0.30%) and DPPH\(\bullet\) scavenging activity (92.56 \(\pm\) 0.56%) of cationic radicals were evaluated in the bovine liver hydrolyses after the effect of papain for 24 h. Longer hydrolysis time influenced the decrease in free hydrophobic amino acids (Ala, Val, Ile, Leu, Tyr, Phe, Pro, Met). The results confirmed the potential use of bovine liver and heart hydrolyses as functional or biologically active materials. by-products; hydrolyses; antioxidant activity; antimicrobial activity +
Footnote †: Academic Editor, [PERSON]. value [10]. Enzymatic hydrolysis using papain and pepsin has been observed to produce the best results for the extraction of antioxidant and anti-inflammatory biopeptides from animal tissues [11]. Animal proteins are rich sources of important amino acids that are typically absent in plant proteins. These include methylhistidine and hydroxymethyllysine, which can be utilized to produce peptides with antioxidant characteristics [12]. The amino acid profile of animal liver is composed of aromatic (tyrosine and phenylalanine) and hydrophobic (leucine, valine, and isoleucine) amino acids, which exhibit high antioxidant activity [13]. Hearts are a protein source of biologically active components with hypolipidemic properties [14]. Thus, the animal liver or heart tissue is a raw material of high biological value, useful as a bioactive source for peptide hydrolysates with increased nutritional and functional value. Isolation of new peptides from animal by-products with antioxidant properties can positively affect meat preservation, preventing lipid oxidation in food products and maintaining unchanged taste and smell [15; 16]. Peptides possessing antioxidant characteristics have the potential to enhance nutritional value when employed as functional components or nutraceuticals [9]. The antioxidant activity and functional qualities of protein hydrolysates are influenced by several factors, such as the conditions under which hydrolysis occurs, the source of the protein, and the specific substrate proteins that are chosen. Protein hydrolysates may have advantages over purified peptides because of the production of oligopeptides due to absorption. Hydrolysates were also observed to have antioxidant activity comparable to purified peptides [17]. The antioxidant properties of peptides derived from meat products are attributed to their ability to inhibit the activity of reactive oxygen species (ROS) and lipid peroxidation and chelation of transition metal ions [18; 19]. Peptides with antimicrobial properties isolated from animal by-products cover a smaller area of research compared to peptides with antioxidant properties [19].