## 4 Discussion
### Bromatological Composition
These phenolic hydroxyl groups confer to the molecules' acid-base properties, allowing them to act as weak acids by donating protons (H\({}^{+}\)) in alkaline conditions. In aqueous solution, the degree of ionization of polyphenols depends on the pH of the surrounding environment: at neutral or basic pH, the hydroxyl groups are more likely to dissociate, resulting in the formation of phenolate anions. This dissociated form is generally less stable, more reactive, and prone to oxidation, especially in the presence of dissolved oxygen or trace amounts of transition metal ions (e.g., Fe\({}^{2+}\), Cu\({}^{2+}\)), which can catalyze the formation of quinones and other degradation products through redox cycling mechanisms [46; 47]. Conversely, under acidic conditions--such as those present in the gastric environment (pH \(\sim\) 2)--the high concentration of H\({}^{+}\) ions suppresses the ionization of the hydroxyl groups, favoring the formation of protonated species. These are typically more water-soluble and chemically stable, which facilitates both their desorption from the food matrix and their resistance to oxidative degradation during digestion [48]. Furthermore, the acidic environment and pepsin activity can promote the hydrolysis of glycosidic or ester bonds that bind polyphenols to complex food structures (e.g., polysaccharides, proteins), enhancing their release and bioaccessibility [49]. In contrast, the reduced recovery of polyphenols after the oral and intestinal phases may reflect their chemical instability at near-neutral pH. At pH 7, polyphenic compounds tend to be more chemically reactive, undergoing autoxidation, polymerization, or structural rearrangements, which not only reduce their quantifiable concentration but may also alter their biological activity [50]. Moreover, in the intestinal phase, the presence of bile salts and pancreatin may influence the solubility and partitioning behavior of phenolics, potentially leading to their precipitation, degradation, or transformation into less detectable forms [51]. These underline the pH-dependent nature of polyphenol stability and release and help explain the enhanced liberation observed during the gastric phase as compared to the oral and intestinal phases. Although the results disclosed a precise trend for the three molecules analyzed, precisely determining the behavior of the polyphenic compounds through the different phases of the digestive process is complex, closely related to the methodology employed, and could give us just an idea of the real release of these compounds [52]. In real physiological conditions, additional variables, such as gut microbiota metabolism, mucosal absorption, and host enzymatic diversity, can significantly affect the fate of these molecules. For instance, microbial fermentation in the colon can lead to further biotransformation of polyphenols into smaller, bioactive metabolites that may exert systemic effects. These aspects are not fully captured in static in vitro models, underscoring the need for complementary in vivo studies to confirm the actual bioavailability and functionality of these compounds after ingestion [53]. Evaluation of the Antioxidant and Growth Inhibition Capacity During the Simulated In Vitro Digestion Process  
The results obtained in this study showed the significant antioxidant properties of _Fucus vesicolusus_, primarily attributed to its high content of polyphenic compounds, particularly phlorotannins [54; 55]. These compounds, as reported in the literature, exhibit strong radical scavenging activity, which is crucial for neutralizing reactive oxygen species (ROS) that contribute to oxidative stress [56]. Although the antioxidant capacity of _F. vesicolusus_ is well established and has been demonstrated by several researchers [51], the maintenance of this property, even after the digestive process, remains poorly understood to date.