Extraction of Protein from Four Different Seaweeds Using Three Different Physical Pre-Treatment Strategies

Abstract

Seaweeds are a rich source of protein and can contain up to 47% on the dry weight basis. It is challenging to extract proteins from the raw biomass of seaweed due to resilient cell-wall complexes. Four species of macroalgae were used in this study-two brown, Fucus vesiculosus and Alaria esculenta, and two red, Palmaria palmata and Chondrus crispus. Three treatments were applied individually to the macroalgal species: (I) high-pressure processing (HPP); (II) laboratory autoclave processing and (III) a classical sonication and salting out method. The protein, ash and lipid contents of the resulting extracts were estimated. Yields of protein recovered ranged from 3.2% for Fucus vesiculosus pre-treated with high pressure processing to 28.9% protein recovered for Chondrus crispus treated with the classical method. The yields of protein recovered using the classical, HPP and autoclave pre-treatments applied to Fucus vesiculosus were 35.1, 23.7% and 24.3%, respectively; yields from Alaria esculenta were 18.2%, 15.0% and 17.1% respectively; yields from Palmaria palmata were 12.5%, 14.9% and 21.5% respectively, and finally, yields from Chondrus crispus were 35.2%, 16.1% and 21.9%, respectively. These results demonstrate that while macroalgal proteins may be extracted using either physical or enzymatic methods, the specific extraction procedure should be tailored to individual species.

Current knowledge on the extraction, purification, identification, and validation of bioactive peptides from seaweed

“…Protein fractions are located in different parts of macroalgae biomass including the cell wall, cytoplasm, and organelles, e.g., phycobiliproteins are located in the chloroplast stroma [8,9]. The reported protein contents in macroalgae vary from 1.3 to 47% (w/w) dry weight, depending on species, growth season, and geographical location of harvest [7,[9][10][11][12][13][14]. Some red seaweeds have higher protein contents than some other protein-rich food sources such as soybean, cereals, eggs, and fish [15].…”

“…Moreover, the physiological and biochemical characteristics, particularly the type of proteins present, in different macroalgal phylae and species can impact the extraction efficiency [14,16]. Additional factors that may affect protein extraction include biomass concentration, extraction temperature, and duration of extraction (protein solubilization or precipitation).…”

“…In addition, O’ Connor et al. [14] demonstrated that sonication combined with ammonium sulfate precipitation resulted in the highest protein recovery from Fucus vesiculosus and Chondrus crispus , i.e., 35.10 and 35.50% (w/w) protein, respectively (Table 2). This was compared to other approaches, e.g., high‐pressure processing or laboratory autoclave treatment that yielded protein recoveries ranging from 16.10‐24.30% (w/w).…”

“…The application of HHP (600 MPa for 4 min) to aid protein extraction from two brown seaweeds, F. vesiculosus and Alaria esculenta , and two red seaweeds, P. palmata and Ch. crispus was investigated [14]. HHP treatment appeared to be the most effective in aiding protein extraction from F. vesiculosus (23.70% (w/w) protein; Table 2).…”

“…The protein recovery achieved following HHP with the other species ranged from 14.90 to 16.10% (w/w). On the contrary, autoclave treatment yielded higher protein content (21.50%, w/w) than the HHP treatment (14.90%, w/w, protein) in the case of P. palmata (Table 2) [14]. However, in the case of So.…”