## 2 Results  
The biodegradation degree dynamics of protein molecules in samples of collagen-containing raw materials (pork skin) depending on the concentration of collagenase and Neutrase 1.5 MG enzyme preparations, pH value, and temperature of the medium is shown in Figures 1-3. The hydrolysis degree values of the samples are comparable to each other; however, a higher rate of the process was observed in the samples with catalase. Table 1 shows generalized results on selecting parameters and substantiating technological modes of biodegradation of collagen-containing waste by collagenase and Neutrase 1.5 MG.  
Figure 1: Study of the biodegradation of protein molecules in samples of collagen-containing raw materials by (**a**) collagenase or (**b**) Neutrase 1.5 MG at various concentrations of the enzyme, U/g: 1–150, 2–200, 3–250, 4–300. Values followed by the same letter do not differ significantly (\(p>0.05\)) as assessed by post hoc test (Tukey test). Figure 2: Results of studying the biodegradation of protein molecules in samples of collagen-containing raw materials by (**a**) collagenase or (**b**) Neutrase 1.5 MG at different pH values: 1–5.0; 2–6.0; 3–7.0; 4–8.0. Values followed by the same letter do not differ significantly (\(p>0.05\)) as assessed by post hoc test (Tukey test). \begin{table}
\begin{tabular}{l c c} \hline \hline \multirow{2}{*}{**Conditions**} & \multicolumn{2}{c}{**Enzyme Preparations**} \\ \cline{2-3}  & **Collagenase** & **Neutrase 1.5 MG** \\ \hline Enzyme concentration, U/g & 250 & 250 \\ Duration, h & 6 & 7 \\ pH & 7.0 & 6.0 \\ Temperature, \({}^{\circ}\)C & 40 & 50 \\ Hydrolysis degree, \% & 77–78 & 72–74 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Generalized results on selecting parameters and substantiation of technological modes of biodegradation of collagen-containing waste by enzyme preparations. Next, we analyzed the amino acid, peptide, and protein profiles of samples of collagen-containing waste hydrolysis products obtained using collagenase and Neutralase 1.5 MG.  
At the first stage of this task, we analyzed the peptide and protein profile of samples of collagen-containing waste hydrolysis products obtained using the collagenase and Neutralase 1.5 MG enzyme preparations. The results of studying the peptide and protein profile of samples of collagen-containing waste hydrolysis products obtained using collagenase and Neutralase 1.5 MG are presented in Table 2.  
Figure 3: Results of studying the biodegradation of protein molecules of samples of collagen-containing raw materials by (**a**) collagenase or (**b**) Neutralase 1.5 MG at different temperatures, \({}^{\circ}\)C: 1–30; 2–35; 3–40; 4–45; 5–50; 6–55. Values followed by the same letter do not differ significantly (\(p>0.05\)) as assessed by post hoc test (Tukey test). Next, we studied the amino acid profile of samples of collagen-containing waste hydrolysis products obtained using collagenase and Neutrase 1.5 MG. The results are presented in Figure 4. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**The Molecular Weight of the Protein Profile, kDa**} & \multicolumn{2}{c}{**The Proportion of Protein and Peptide Fraction in the Hydrolyzate, \%**} \\ \cline{2-3}  & **I** & **II** \\ \hline
66.0–89.0 & 0.1 \(\pm\) 0.003 & 0.3 \(\pm\) 0.001 \\
57.0–65.0 & 0.8 \(\pm\) 0.02 & 0.6 \(\pm\) 0.02 \\
45.0–57.0 & 3.6 \(\pm\) 0.11 & 3.8 \(\pm\) 0.11 \\
36.0–45.0 & 2.1 \(\pm\) 0.06 & 1.9 \(\pm\) 0.05 \\
29.0–36.0 & 23.8 \(\pm\) 0.71 & 22.4 \(\pm\) 0.72 \\
14.0–29.0 & 15.7 \(\pm\) 0.47 & 14.5 \(\pm\) 0.46 \\
6.5–14.0 & 13.4 \(\pm\) 0.40 & 12.8 \(\pm\) 0.38 \\
3.5–6.5 & 37.6 \(\pm\) 0.45 & 39.2 \(\pm\) 1.17 \\
3.0–3.5 & 48.3 \(\pm\) 1.44 & 46.7 \(\pm\) 1.40 \\ \hline \hline \end{tabular}  
*—collagen waste hydrolyzate obtained by collagenase; II—collagen-containing waste hydrolyzate obtained by Neutrase 1.5 MG.  
\end{table}