Abstract: The proximate chemical composition and amino acid composition of the soft part from Mactra veneriformis were analyzed. Based on dry weight, the contents of protein and lipid were 60.14% and 6.08%, respectively, and the content of 17 identified amino acids was determined to be 48.09%, and the content of essential amino acids (EAA) was 18.94% and of delicious amino acids (DAA) 22.73%, making up 39.38% and 47.27% of total amino acids, respectively. Natural extract (protein) extraction from the soft part from Mactra veneriformis was performed by homogenization with water, pH adjustment and extraction with NaCl. Based on one-factor-at-a-time experiments, response surface methodology (RSM) was employed to optimize the preparation process. The optimal extraction conditions were extraction temperature of 82.07 ℃, pH 7.87 and NaCl concentration of 1.75%. Under these conditions, the protein recovery reached up to 54.78%.

Key words: Mactra veneriformis, composition, natural extract, response surface methodology (RSM)