Impact of alkaline solution, carbohydrase and biomass:solvent on extraction efficiency, and protein and amino acid profiles of Palmaria palmata protein extracts

The impact of using different alkaline solutions, carbohydrases and changing the biomass to solvent volume ratio (biomass:solvent) on protein content, protein and biomass yield recovery in protein enriched extracts from Palmaria palmata (red seaweed) was studied. Protein extraction with alkaline solutions, i.e., NaOH, KOH, Ca(OH)₂ and Na₂CO₃ (at 0.12 M) along with (and without) carbohydrases B, BD and L (containing xylanase, a mixture of xylanase and cellulase, and a combination of cellulase, xylanase and polygalacturonase activities, respectively) was assessed. Principal component analysis was used to assess correlations (if any) between the different alkaline solvents, carbohydrases and changing biomass:solvent on extraction efficiency. The highest protein content (56.64 ± 0.43 % (w/w)) was obtained using KOH assisted extraction with carbohydrase BD. The highest protein and biomass yield recoveries (70.65 ± 1.38 and 21.99 ± 0.43 % (w/w), respectively) were obtained on extraction using NaOH assisted with carbohydrases BD. Electrophoretic, amino acid profile and amino acid score analyses displayed differences depending on the alkaline solvent used for protein extraction. Appropriate selection of the alkaline solvent, carbohydrase and biomass:volume combination during protein extraction can contribute to the production of compositionally enhanced high-quality protein concentrates from P. palmata.