Characterization of salmon (Oncorhynchus keta) and sturgeon (Acipenser transmontanus) caviar proteins

The solubility of protein components in salmon (Oncorhynchus keta) and sturgeon (Acipenser transmontanus) caviar in distilled water, 5% (w/v) NaCl, 70% (v/v) ethanol at 65C, and 0.2% (w/v) NaOH was determined. The salt soluble proteins were the predominant fraction and constituted 84.2% of the recovered protein in salmon and 86.1% in sturgeon samples. The two most prominent protein fractions (12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis) for sturgeon caviar are most likely vitellin (96 kDa) and ovomucoid or phosvitin (28 kDa). For salmon roe, small proteins, possibly lysozyme or phosvitin (10 kDa), are also present.