## 3 Results
### Thermal Decomposition Profiles of the Swim Bladder
\begin{table}
\begin{tabular}{c c c c c} \hline  & **FSB** & **1-YSB** & **5-YSB** & **25-YSB** \\ \hline Collagen (\%) & 35.41 \(\pm\) 0.70 \({}^{\text{b}}\) & 75.36 \(\pm\) 0.47 \({}^{\text{a}}\) & 77.03 \(\pm\) 13.38 \({}^{\text{a}}\) & 90.38 \(\pm\) 3.02 \({}^{\text{a}}\) \\ Moisture (\%) & 56.98 \(\pm\) 1.04 \({}^{\text{a}}\) & 16.00 \(\pm\) 0.46 \({}^{\text{b}}\) & 14.63 \(\pm\) 0.57 \({}^{\text{b}}\) & 10.31 \(\pm\) 0.20 \({}^{\text{c}}\) \\ Moisture and collagen in total (\%) & 92.21 \(\pm\) 0.43 \({}^{\text{a}}\) & 91.12 \(\pm\) 0.16 \({}^{\text{a}}\) & 91.34 \(\pm\) 13.19 \({}^{\text{a}}\) & 100.58 \(\pm\) 2.95 \({}^{\text{a}}\) \\ \multicolumn{5}{c}{Amino acid composition (mol \%)} \\ Glycine & 33.50 \(\pm\) 0.23 \({}^{\text{a}}\) & 35.34 \(\pm\) 2.34 \({}^{\text{a}}\) & 33.48 \(\pm\) 0.62 \({}^{\text{a}}\) & 33.54 \(\pm\) 0.44 \({}^{\text{a}}\) \\ Hydroxyproline & 9.57 \(\pm\) 1.54 \({}^{\text{a}}\) & 8.85 \(\pm\) 2.46 \({}^{\text{a}}\) & 8.80 \(\pm\) 0.21 \({}^{\text{a}}\) & 9.42 \(\pm\) 0.25 \({}^{\text{a}}\) \\ Proline & 18.81 \(\pm\) 0.53 \({}^{\text{a}}\) & 12.31 \(\pm\) 0.57 \({}^{\text{b}}\) & 13.15 \(\pm\) 0.28 \({}^{\text{b}}\) & 12.43 \(\pm\) 0.02 \({}^{\text{b}}\) \\ Arginine & 1.26 \(\pm\) 0.02 \({}^{\text{c}}\) & 2.11 \(\pm\) 0.13 \({}^{\text{a}}\) & 1.81 \(\pm\) 0.03 \({}^{\text{a}}\) \({}^{\text{b}}\) & 1.72 \(\pm\) 0.08 \({}^{\text{b}}\) \\ Valine & 2.13 \(\pm\) 0.03 \({}^{\text{b}}\) & 2.65 \(\pm\) 0.08 \({}^{\text{a}}\) & 1.25 \(\pm\) 0.02 \({}^{\text{c}}\) & 1.38 \(\pm\) 0.002 \({}^{\text{c}}\) \\ Methionine & 1.74 \(\pm\) 0.04 \({}^{\text{b}}\) & 2.09 \(\pm\) 0.07 \({}^{\text{a}}\) & 1.45 \(\pm\) 0.02 \({}^{\text{c}}\) & 0.54 \(\pm\) 0.003 \({}^{\text{d}}\) \\ Isoleucine & 0.67 \(\pm\) 0.03 \({}^{\text{b}}\) & 3.10 \(\pm\) 0.08 \({}^{\text{a}}\) & 0.46 \(\pm\) 0.01 \({}^{\text{c}}\) & 0.44 \(\pm\) 0.01 \({}^{\text{c}}\) \\ Leucine & 2.55 \(\pm\) 0.02 \({}^{\text{a}}\) & 0.94 \(\pm\) 0.04 \({}^{\text{c}}\) & 2.46 \(\pm\) 0.05 \({}^{\text{a}}\) & 2.26 \(\pm\) 0.02 \({}^{\text{b}}\) \\ Phenylalanine & 1.59 \(\pm\) 0.05 \({}^{\text{b}}\) & 1.79 \(\pm\) 0.05 \({}^{\text{a}}\) & 1.31 \(\pm\) 0.02 \({}^{\text{c}}\) & 1.27 \(\pm\) 0.001 \({}^{\text{c}}\) \\ Lysine & 3.36 \(\pm\) 0.08 \({}^{\text{a}}\) & 3.35 \(\pm\) 0.09 \({}^{\text{a}}\) & 2.77 \(\pm\) 0.06 \({}^{\text{b}}\) & 2.96 \(\pm\) 0.01 \({}^{\text{b}}\) \\ Alanine & 4.74 \(\pm\) 0.22 \({}^{\text{d}}\) & 11.80 \(\pm\) 0.12 \({}^{\text{a}}\) & 10.06 \(\pm\) 0.16 \({}^{\text{c}}\) & 10.86 \(\pm\) 0.12 \({}^{\text{b}}\) \\ Tyrosine & 0.79 \(\pm\) 0.03 \({}^{\text{b}}\) & 1.01 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.71 \(\pm\) 0.02 \({}^{\text{b}}\) & 0.42 \(\pm\) 0.02 \({}^{\text{c}}\) \\ Aspartic acid & 7.87 \(\pm\) 0.99 \({}^{\text{a}}\) & 5.10 \(\pm\) 0.08 \({}^{\text{b}}\) & 5.74 \(\pm\) 0.69 \({}^{\text{a}}\) & 5.95 \(\pm\) 0.04 \({}^{\text{b}}\) \\ Glutamate & 6.04 \(\pm\) 0.28 \({}^{\text{b}}\) & 6.42 \(\pm\) 1.23 \({}^{\text{b}}\) & 11.54 \(\pm\) 0.23 \({}^{\text{a}}\) & 11.37 \(\pm\) 0.002 \({}^{\text{a}}\) \\ Serine & 5.38 \(\pm\) 0.13 \({}^{\text{a}}\) & 3.13 \(\pm\) 0.17 \({}^{\text{b}}\) & 4.09 \(\pm\) 0.03 \({}^{\text{b}}\) & 5.44 \(\pm\) 0.50 \({}^{\text{a}}\) \\ Totalimino acids \({}^{\text{2}}\) & 28.38 \(\pm\) 1.01 \({}^{\text{a}}\) & 21.16 \(\pm\) 1.90 \({}^{\text{b}}\) & 21.94 \(\pm\) 0.49 \({}^{\text{b}}\) & 21.85 \(\pm\) 0.27 \({}^{\text{b}}\) \\ \hline \end{tabular} \({}^{1}\) Values are means \(\pm\) SDs (\(n\) = 3). Values with different superscript letters within the same row are significantly different (\(p\) < 0.05). \({}^{\text{2}}\) Total amino acids were composed of proline and hydroxproline.  
\end{table} 
Table 1: Basic compositions of FSB, 1-YSB, 5-YSB, and 25-YSB \({}^{\text{1}}\). Figure 2: TG-DTG (**A**) and DSC (**B**) observations of the decompositions of peptide chains and triple helix structures in FSB (a), 1-YSB (b), 5-YSB(c), 25-YSB (d), and TDSB (e). The triple helix is composed of three peptide chains but is sensitive to thermal treatment.