Protein Dispersions and Hydrolysates from Shark (Isurus oxyrinchus)

Abstract
Manually-deboned muscles of shark (Isurus oxyrinchus) were ground and then washed sequentially with water, 0.5% NaCl and 0.5% NaHC03 solutions. Washed myofibrillar proteins were dispersed in water and then acidified. Dispersions so obtained were stable to heat treatment at 100°C followed by centrifugation at 5000 x g, as approximately 90% of proteins remained in solution. The acidified dispersions had low solubility in the pH range of 5 to 8, but were highly soluble under other pH conditions. Apparent viscosity of dispersions was dependent on temperature, pH and protein concentration. The amino acid composition and calculated protein efficiency ratio (PER) of washed proteins were similar to that of the original meat; howevcr, over 85% of free amino acids were removed upon aqueous washings of the meat. Hydrolysates obtained via an Alcalase-assisted process from the original shark muscles or washed myofibrillar proteins exhibited unique functional characteristics with respect to their water-holding capacity and emulsifying properties.