Extraction of protein from red crab (Chionoeoets japonicus) shell by commercial proteases and their characteristics

Abstract

To examine the possibility of usage as a protein source, red crab shell was enzymatically hydrolyzed using 6 commercial proteases (Protease A, Protamex, Neutrase, Favourzyme, Alcalase, Protease M for 24 hrs at its optimum pH and temperature. Protein concentration of hydrolysate was examined by using Bradford method, ninhydrin method, Biuret method and OD at 280nm. Recovery rate and molecular weight of protein by various enzyme treatments was different. Protease A was the most effective enzyme to hydrolyze protein from crab shell. To obtain synergistic effect of protein extraction, combination of enzymes were tried. Significant increase in protein recovery was observed when Protease A was co‐treated with Protamex, its recovery rate was increased 5‐fold compared to Protease A alone. Amino acid composition was somewhat variable by enzyme treatments. Nonetheless, Phenylalanine, glycine, alanine, and lysine were abundant amino acids, whereas tyrosine was only amino acid not detected. (This research was supported by Technology Development Program for Fisheries, Ministry for Food, Agriculture, Forestry and fisheries, Republic of Korea)