## 3 Results
### Effects of Cooking Methods on the Quality of L. japonica
#### 3.1.2 Effects of Cooking Methods on the TPA of \(L\). _japonica_  
The effects of different processing methods on the texture of _Laminaria japonica_ are shown in Table 1. The texture analyzer was used to determine the hardness, cohesiveness, \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **Raw** & **Blanched** & **Steamed** & **Boiled** & **Baked** \\ \hline \multirow{4}{*}{Color} & \(L^{\bullet}\) & \(20.15\pm 1.15\,\mathrm{b}^{\text{ }}\) & \(21.17\pm 0.76\,\mathrm{b}^{\text{ }}\) & \(19.96\pm 1.78\,\mathrm{b}^{\text{ }}\) & \(20.95\pm 0.84\,\mathrm{b}^{\text{ }}\) & \(27.58\pm 1.40\,\mathrm{a}^{\text{ }}\) \\  & \(a^{\bullet}\) & \(-0.22\pm 0.11\,\mathrm{b}^{\text{ }}\) & \(-0.45\pm 0.14\,\mathrm{c}^{\text{ }}\) & \(-0.55\pm 0.18\,\mathrm{c}^{\text{ }}\) & \(0.48\pm 0.19\,\mathrm{a}^{\text{ }}\) & \(0.67\pm 0.22\,\mathrm{a}^{\text{ }}\) \\  & \(b^{\bullet}\) & \(5.78\pm 0.83\,\mathrm{a}^{\text{ }}\) & \(4.45\pm 0.40\,\mathrm{b}^{\text{ }}\) & \(5.29\pm 0.82\,\mathrm{a}^{\text{ }}\) & \(5.30\pm 0.96\,\mathrm{a}^{\text{ }}\) & \(4.97\pm 0.98\,\mathrm{a}^{\text{ }}\) \\  & \(\Delta E\) & nd & 1.69 & 0.61 & 1.18 & 7.52 \\  & Hardness (g) & \(1513.73\pm 103.87\,\mathrm{a}^{\text{ }}\) & \(1348.21\pm 118.54\,\mathrm{b}^{\text{ }}\) & \(1085.80\pm 101.07\,\mathrm{c}^{\text{ }}\) & \(1495.20\pm 105.38\,\mathrm{a}^{\text{ }}\) & \(360.05\pm 112.053\,\mathrm{a}^{\text{ }}\) \\  & Cohesiveness & \(1.04\pm 0.17\,\mathrm{a}^{\text{ }}\) & \(0.99\pm 0.02\,\mathrm{a}^{\text{ }}\) & \(0.96\pm 0.02\,\mathrm{a}^{\text{ }}\) & \(0.99\pm 0.03\,\mathrm{a}^{\text{ }}\) & \(0.89\pm 0.14\,\mathrm{b}^{\text{ }}\) \\ TPA & Adhesiveness (g,s) & \(0.67\pm 0.02\) & \(0.67\pm 0.04\) & \(0.60\pm 0.04\,\mathrm{0}\) & \(0.65\pm 0.01\,\mathrm{0}\) & \(0.58\pm 0.31\,\mathrm{a}^{\text{ }}\) \\  & Chewiness (g) & \(1044.65\pm 160.11\,\mathrm{a}^{\text{ }}\) & \(976.93\pm 304.12\,\mathrm{a}^{\text{ }}\) & \(626.84\pm 105.97\,\mathrm{b}^{\text{ }}\) & \(953.46\pm 57.72\,\mathrm{a}^{\text{ }}\) & \(140.44\pm 126.20\,\mathrm{c}^{\text{ }}\) \\  & Resilience & \(0.53\pm 0.03\,\mathrm{a}^{\text{ }}\) & \(0.48\pm 0.05\,\mathrm{a}^{\text{ }}\) & \(0.42\pm 0.05\,\mathrm{b}^{\text{ }}\) & \(0.39\pm 0.02\,\mathrm{c}^{\text{ }}\) & \(0.30\pm 0.08\,\mathrm{a}^{\text{ }}\) \\ \hline \end{tabular} Data are expressed as mean \(\pm\) standard deviation (\(n=9\)). Means in columns followed by different letters differ significantly (\(p\leq 0.05\)). nd, not determined.  
\end{table} 
Table 1: Influence of different processing methods on the color and TPA of \(L\). _japonica_. Figure 1: Raw and cooked \(L\). _japonica_ by different methods. The processing methods of \(L\). _japonica_ from left to right are (**a**) raw; (**b**) blanching; (**c**) steaming; (**d**) boiling; (**e**) baking. adhesiveness, chewiness, and resilience of the untreated \(L\). _japonica_. The results showed that, with the exception of adhesiveness, the textural characteristics of kelp cooked in different processing methods changed more significantly compared to raw kelp (\(p<0.05\)). Among them, the texture of boiled kelp was most similar to that of raw kelp (no significant difference, \(p>0.05\)) except for the resilience. On the contrary, the texture of kelp after baking changed most obviously. Hardness is a physical index that describes the strength required for chewing food. Moreover, hardness is probably the most relevant texture feature for solid foods and plays a key role in consumer acceptance and market value. Compared with raw kelp, the hardness of processed kelp was significantly reduced (\(p<0.05\)). The decrease in the hardness value of the kelp was probably due to the thermal decomposition of the polysaccharides (alginate) in the kelp cell walls, which formed a porous structure, resulting in a decrease in its hardness [20]. Similar to our results, [PERSON] et al. found that the hardness values of _Undaria pinnatifida_ decreased significantly after different cooking methods compared to the raw samples [18].