Study on the protein fractions extracted from the muscle tissue of Pinctada martensii and their hydrolysis by pancreatin

Summary Pinctada martensii muscle proteins were separated into water‐soluble, salt‐soluble and insoluble protein fractions. The salt‐soluble protein fraction was the most abundant, comprising approximately 66.3% of the protein, followed by the water‐soluble and insoluble protein fractions in decreasing order. sodium dodecyl sulphate polyacrylamide gel electrophoresis profiles showed that 35‐ and 97‐kDa peptides represented the highest proportions of the water‐soluble and salt‐soluble protein fractions, respectively. The three protein fractions contained high levels of flavourful amino acids (Glu, Asp, Ala and Lys), with the water‐soluble protein fraction having the highest level (47.1%). The size exclusion chromatography profiles of the water‐soluble and salt‐soluble protein pancreatin hydrolysate demonstrated no significant differences in the molecular weight distributions in the >20 000, 5000–10 000 and 2000–5000 Da fractions, while those of the insoluble protein pancreatin hydrolysate were different. In conclusion, the results provided some basic information that would contribute to the utilisation of these protein fractions.