## 3 Results
### Chemical Characterization
\begin{table}
\begin{tabular}{l c c c c} \hline \hline \multicolumn{1}{c}{**VOCs**} & \multicolumn{3}{c}{**Days**} & \multicolumn{3}{c}{_Porphyra umbilicalis_} \\  & & _CTRL_ & _MAP_ & _VAC_ \\ \hline  & Day 0 & 10.878 \(\pm\) 4.982 & — & — \\ _8-Heptadecene_ (_isomer 2_) & Day 3 & 7.346 \(\pm\) 0.801 & 19.952 \(\pm\) 1.836 & 28.141 \(\pm\) 2.848 \\ CAS\# N/D & Day 6 & 12.577 \(\pm\) 1.852 & 24.026 \(\pm\) 3.459 & 29.272 \(\pm\) 1.133 \\  & Day 9 & 10.939 \(\pm\) 1.969 & 23.277 \(\pm\) 2.356 & 22.992 \(\pm\) 1.849 \\ Threshold: N/D & Day 12 & 12.219 \(\pm\) 0.368 & 25.666 \(\pm\) 1.829 & 32.619 \(\pm\) 3.041 \\  & Day 15 & 14.501 \(\pm\) 1.913 & 27.679 \(\pm\) 3.405 & 5.527 \(\pm\) 1.823 \\ \hline  & Day 0 & 3.037 \(\pm\) 1.524 & — & — \\ _Heptadecane_ & Day 3 & 0.924 \(\pm\) 0.024 & 7.098 \(\pm\) 0.955 & 6.817 \(\pm\) 0.667 \\ CAS\# 629-78-7 & Day 6 & 1.109 \(\pm\) 0.058 & 7.92 \(\pm\) 1.481 & 8.552 \(\pm\) 0.732 \\  & Day 9 & 0.961 \(\pm\) 0.290 & 6.77 \(\pm\) 0.710 & 6.648 \(\pm\) 0.185 \\ Threshold: N/D & Day 12 & 1.192 \(\pm\) 0.048 & 7.41 \(\pm\) 0.338 & 7.271 \(\pm\) 0.559 \\  & Day 15 & 2.037 \(\pm\) 0.262 & 10.283 \(\pm\) 0.975 & 1.143 \(\pm\) 0.418 \\ \hline  & Day 0 & 1.826 \(\pm\) 0.464 & — & — \\ _Pentadecanal_ & Day 3 & 17.544 \(\pm\) 0.702 & 8.747 \(\pm\) 0.709 & 0.695 \(\pm\) 0.011 \\ CAS\# 2765-11-9 & Day 6 & 10.309 \(\pm\) 0.124 & 25.939 \(\pm\) 3.018 & 1.529 \(\pm\) 0.689 \\  & Day 9 & 12.627 \(\pm\) 3.127 & 25.229 \(\pm\) 2.091 & 1.993 \(\pm\) 0.531 \\ Threshold: 0.715 mg/kg & Day 12 & 23.097 \(\pm\) 0.329 & 19.565 \(\pm\) 1.615 & 2.827 \(\pm\) 0.132 \\  & Day 15 & 12.968 \(\pm\) 1.836 & 11.103 \(\pm\) 0.539 & 1.732 \(\pm\) 0.549 \\ \hline \hline \end{tabular} Notes: The results are expressed as the percentage (%) of the respective peak area relative to the total peak area. Odor thresholds in water were calculated using the median for the values compiled by [PERSON] (1997).  
\end{table} 
Table 1: Main VOCs responsible for the variation in _P. umbilicalis_ samples according to the PCA. Figure 8: PCA of the seaweed treatments and storage periods. Bi-plot graphics containing scores and loads of: (**a**) PC-1 vs. PC-2 for _P. umbilicalis_, (**b**) PC-1 vs. PC-2 for _U. lactuca_, (**c**) PC-1 vs. PC-3 for _U. lactuca_, and (**d**) PC-2 vs. PC-3 for _U. lactuca_. In the case of UL seaweed (Table 2), both (_E,E_)-2_A_-decadien and its isomer exhibited similar behavior in CTRL over the storage period. Initially, they contributed a major share of volatiles on day 0 (12.425% and 27.565%, respectively) and, to a lesser extent, on day 3 (4.018% and 9.401%, respectively). However, the values kept falling from day 6 onwards. Regarding the MAP treatment, after an initial drop on day 3, the concentrations of 2,4-decadienals kept increasing for both compounds until day 12, with more intensity for (_E,E_)-2,4-decadienal. By the end of the storage period, there was another accentuated decrease. Regarding the VAC treatment, the values of both 2,4-decadienals also presented some variation, although they displayed a similar behavior: the values kept falling, with more intensity for the isomer, reaching the lowest concentration on day 9. On day 12, they increased again, with minor changes on day 15. In the case of 1-hexanol, its concentration increased in CTRL until day 12, with values ranging from 0.133% to 24.474%, after which it decreased to the value of 4.760%. In the other treatments, their values showed a slight rise compared to the control on day 0 but remained relatively stable until the end of the storage period. Regarding benzaldehyde, it experienced a considerable increase in concentration for CTRL and both MAP and VAC treatments, with a notable importance of samples packed under a modified atmosphere (from 2.287% to 33.800%). As for 8-heptadecene (isomer 1), it demonstrated a similar behavior across all samples. There was a tendency for its concentration to increase until