## 5 Conclusions  
The results obtained on the impact of minimal processing on the seaweeds \"layer\" (_Porphyna umbilicalis_) and \"sea-lettuce\" (_Ulva lactuca_) showed that these allowed for safe consumption for a minimum period of 15 days. The composition of headspace gases indicated that the MAP treatment and storage conditions were able to keep photosynthesis and respiration rates low. The degradation of pigments caused discoloration in both seaweeds. However, the MAP preservation technique appeared to be the most effective in maintaining the color of both seaweeds. Regarding texture, our findings indicated that MAP may be superior to VAC in preserving the fresh seaweed's textural properties. By the end of the storage period, both seaweeds treated with MAP and VAC complied with the primary microbiological criteria specified by regulations. Notably, both these treatments yielded significant improvements for PU, with microbial counts below the limits of detection on day 15, while for UL, neither treatment seemed to have a substantial effect on reducing the microbial load. Despite some variations in VOCs, there was no notable change in the distinct aroma of the seaweeds studied. However, both the MAP and VAC treatments demonstrated greater effectiveness in preserving the sensory characteristics of UL compared to PU, with no significant differences observed during storage. Metabolic responses to diverse sources of abiotic stress such as temperature (cold damage), light and other parameters related to storage conditions (e.g., lack of nutrients or wounds caused by handling and packaging), together with metabolic activities at the level of the microbiome appeared to have accounted for most of the changes observed through the analytical methods applied. The use of MAP proved to be a promising method for preserving minimally processed seaweed, surpassing the effectiveness of vacuum packaging in most of the studies. It should be noted that the results obtained from the analyzed seaweeds provide evidence that different species exhibit varied behaviors based on the applied treatments, underscoring the need for the immediate exploration of this preservation technique in other types of marine macroalgae. The present study displays some limitations, which have been previously discussed. To enhance the understanding of the key compounds that contribute to the distinctive aroma of the seaweeds under investigation, employing techniques such as GC-O and sensory analysis would be of great value. Ideally, in conjunction with conventional cultivation methods, methodologies such as 16S rRNA gene sequencing could aid in identifying the taxonomic composition of the microbiota present. Moreover, expanding the sample size with true replicates and conducting additional repetitions would help to minimize data variability. The present work represents a first step towards studying minimal processing techniques with the aim of better preserving the organoleptic characteristics of seaweeds. Further research in this area is required, in particular the study of the impact of other MAP gas mixtures, storage temperatures, or lighting settings. Additionally, enhancements in packaging conditions should also be considered; for example, incorporating a nutrient source such as sterilized seawater or exploring the creation of a protective membrane to prevent the seaweeds from experiencing desiccation. Further research to demonstrate the impact of these techniques on the nutritional characteristics, microbial diversity, or acceptance by the consumer market is also important. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/foods12142736/s1](https://www.mdpi.com/article/10.3390/foods12142736/s1)]([https://www.mdpi.com/article/10.3390/foods12142736/s1](https://www.mdpi.com/article/10.3390/foods12142736/s1)). Table S1: Color changes and color simulation throughout storage days for _P. umbilicalis_ and _U. lactuca_ preserved by different treatments; Table S2: Microbial counts for Coliforms, _E.