## 4 Discussion
### Physicochemical Characterization  
#### 4.2.1 [PERSON] et al. [76] investigated the effect of supercooling conditions on the conservation of _Pyropia yezensis_. This was the only study encountered on the effect of storage conditions on the color of fresh \"layer\" seaweed. The main remarks were that \(L^{*}\), \(a^{*}\) and \(b^{*}\) values of the refrigerated fresh samples (stored at 5 \({}^{\circ}\)C) were affected by the storage temperature with the CIELAB values increasing more than that of the other samples stored at constant and step-cooling (\(-2\)\({}^{\circ}\)C) or frozen (\(-18\)\({}^{\circ}\)C), during the storage period of 15 days. This is not in accordance with our results in which there was a small decrease in \(a^{*}\) and no significant difference in \(b^{*}\) for PU-CTRL after 15 days of storage. It is possible that the differences between the results obtained by [PERSON] et al. and our results for PU-CTRL were due to the different experimental settings such as illumination [77; 78]. Because of the differences in how the MAP and VAC samples were treated, it is not reasonable to establish correlations between the studies. [PERSON] et al. [32] did not find significant differences for \(L^{*}\) in _Ulva lactuca_ in the first 30 days of storage for untreated samples (controls) refrigerated at 4 \({}^{\circ}\)C. No significant difference was found for parameters \(a^{*}\) or \(b^{*}\) for the control; however, similarly to our study, a tendency towards an increase in \(a^{*}\) on the green side of the axis and a decrease in \(b^{*}\) on the yellow side of the axis might be observed. According to the authors, the main changes in color parameters for the control could be attributed, in part, to the amplification of antenna complex pigments under the low-light conditions. [PERSON] et al. [20] evaluated the impact of storage time in the CIELAB coordinates for _Ulva rigida_ treated under different conditions (air-dried, brined, salted with 28% NaCl and salted 40% with NaCl). Despite the differences in the experimental conditions, the conclusions were like those observed in the present study for the \(L^{*}\) and \(a^{*}\) coordinates--i.e., there was a tendency for both values to increase, with \(a^{*}\) being on the green side of the axis. [PERSON] et al. [79] studied the impact of the storage period (12 days) and two different temperatures (4 \({}^{\circ}\)C and 16 \({}^{\circ}\)C) in the color profile of untreated _Ulva rigida_. The results were in accordance with our findings: an increase in \(a^{*}\) on the green part of the axis, a decrease in \(b^{*}\) on the yellow part of the axis and ambiguous values for \(L^{*}\) that decreased in samples stored at 4 \({}^{\circ}\)C and increased in those at 16 \({}^{\circ}\)C. The key findings were that temperature appeared to have a significant impact on color, especially when _U. rigida_ was stored at higher temperatures. Furthermore, from the sixth day of storage onwards, a more pronounced browning of the seaweed was observed. Browning in seaweeds is related to the destruction of the tissue itself, breakdown of chlorophyll compounds (into pheophytin and pheophorbide), alteration caused by enzymatic (e.g., polyphenol oxidase) and non-enzymatic activity, as well due to microbial growth [79; 80]. Different from the treatments that did not seem to significantly affect lightness in PU and only affected UL-VAC on day 6 and UL-MAP on day 15, our results showed that storage time had a positive impact on \(L^{*}\) values (whitening) for PU-VAC, UL-CTRL and UL-VAC. [PERSON] et al. [81] studied the color of _Porphyna umbilicalis_ and _Ulva fenestrata_ after oven-drying at 40 \({}^{\circ}\)C, and during subsequent storage for \(\geq\)370 days under light, semi-light and dark conditions. The main conclusion regarding lighting conditions and storage time was that the more intense the light used and the duration of the storing, the greater the increase in \(L^{*}\) values.