## 3 Results and Discussions
### Morphology Change  
Figure 5 CK1-C4 demonstrate the morphology variations in muscle tissues of the HTS fillets at day 18 stored at 4 \({}^{\circ}\)C. The myofibril could be seen clearly in fresh fillets with rod-like structure caused by the reduction of water-holding capacity of fish fillets. The destruction level of microstructure in treated samples were lower than that of CK1 and CK2 at the same storage time, indicating chitosan-based coating containing \(\varepsilon\)-PL and RA has a better performance in preserving the integrity of myofibril in the fillets, probably owing to the deterioration and degradation of myofibrillar proteins. Previous literature depicted that reduced mechanical restraint of fiber nets caused the immobilized water loss and brought about the conversion of secondary structure by decreasing the force of hydrogen bonds [36]. The disordered arrangement of myofibril enhanced during storage was consistent with the results of LF-NMR parameter.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Percentage** & **CK1** & **CK2** & **C1** & **C2** & **C3** & **C4** \\
**of T\({}_{2l}\)** & & & & & & & \\ \hline \(T_{21}\) & – & – & – & – & – & – & – \\
0 day & \(0.82\pm 0.06\)A, a & \(0.82\pm 0.06\)A, a & \(0.82\pm 0.06\)A, a & \(0.82\pm 0.02\)A, a & \(0.82\pm 0.06\)A, a & \(0.82\pm 0.06\)A, ab \\
6 & \(0.93\pm 0.04\)A, b & \(0.94\pm 0.04\)A, b & \(0.93\pm 0.02\)A, b & \(0.92\pm 0.08\)A, bc & \(0.85\pm 0.05\)B, a & \(0.85\pm 0.038\), ab \\
12 & \(0.86\pm 0.07\)A, ab & \(1.01\pm 0.03\)A, c & \(0.92\pm 0.06\)A, c & \(0.89\pm 0.05\)B, b & \(0.93\pm 0.02\)B, b & \(0.79\pm 0.02\)C, a \\
18 & \(0.94\pm 0.02\)A, b & \(0.97\pm 0.04\)A, bc & \(0.99\pm 0.04\)A, c & \(0.93\pm 0.09\)B, bc & \(0.88\pm 0.04\)B, ab & \(0.88\pm 0.04\)C, b \\
72 & – & – & – & – & – & – & – \\
0 day & \(94.19\pm 0.23\)A, a & \(94.19\pm 0.23\)A, a & \(94.19\pm 0.23\)A, a & \(94.19\pm 0.23\)A, a & \(94.19\pm 0.23\)A, a & \(94.19\pm 0.23\)A, a \\
6 & \(86.81\pm 0.29\)B, a & \(88.02\pm 0.24\)B, ab & \(90.11\pm 0.57\)B, c & \(92.36\pm 0.74\)AB, c & \(89.36\pm 0.32\)B, b & \(89.44\pm 0.498\), b \\
12 & \(78.58\pm 0.17\)C, a & \(80.43\pm 0.32\)C, ab & \(86.36\pm 0.42\)C, c & \(88.17\pm 0.82\)B, cd & \(84.92\pm 0.63\)C, b & \(84.37\pm 0.54\)C, b \\
18 & \(69.68\pm 0.22\)D, a & \(71.67\pm 0.31\)D, ab & \(75.97\pm 0.68\)D, c & \(80.48\pm 0.73\)C, d & \(74.93\pm 0.58\)D, b & \(75.25\pm 0.67\)D, bc \\ \(T_{23}\) & – & – & – & – & – & – & – \\
0 day & \(4.99\pm 0.17\)A, a & \(4.99\pm 0.17\)A, a & \(4.99\pm 0.17\)A, a & \(4.99\pm 0.17\)A, a & \(4.99\pm 0.17\)A, a \\
6 & \(12.26\pm 0.24\)B, a & \(11.04\pm 0.37\)B, ab & \(8.96\pm 0.35\)B, c & \(6.72\pm 0.54\)B, d & \(9.79\pm 0.52\)B, b & \(9.71\pm 0.45\)B, b \\
12 & \(20.56\pm 1.54\)C, a & \(18.56\pm 1.26\)C, b & \(12.43\pm 1.32\)C, d & \(10.93\pm 1.03\)C, dc & \(14.15\pm 1.19\)C, cd & \(14.84\pm 1.21\)C, c \\
18 & \(29.38\pm 1.68\)D, a & \(27.36\pm 1.26\)D, b & \(23.04\pm 1.24\)D, d & \(18.59\pm 1.42\)D, e & \(24.19\pm 1.92\)D, c & \(23.87\pm 1.42\)D, cd \\ \hline \hline \end{tabular}  
* Different uppercase letters in same group from different day indicate a significant difference (\(p<0.05\)).