Protein, Peptide, Amino Acid Profiles, and In Vitro Digestibility of the Edible Red Seaweed Palmaria palmata Grown under Different Nutrient and Lighting Conditions

This study examined how different photoperiods and nutrient conditions influence the protein composition of Palmaria palmata and evaluated the peptides released after simulated gastrointestinal digestion using the INFOGEST in vitro protocol. Two photoperiods (long (16:8) and short (12:12)) and three different levels of nutrient medium (F/2) were used to culture P. palmata tips for 12 days. Nutrient enrichment under the short photoperiod led to higher overall protein (14.3 ± 0.2%) and amino acid (19 ± 1%) levels. Different degrees of protein hydrolysis (DH, 37 ± 2 to 49 ± 3%) were obtained as a function of the level of F/2 employed. A total of 35 peptide sequences were identified following in vitro gastrointestinal digestion, two of which were part of sequences reported as being bioactive in the BIOPEP database. These findings advance current understanding of how environmental and nutrient conditions modulate nutritional quality and digestibility of the red macroalgal protein.