Enzymatic hydrolysis and synthesis of soy protein to improve its amino acid composition and functional properties

Soy protein was enzymatically modified and ultrafiltred, and functional pro perties were evaluated. After enzymatic hydrolysis, hydrolysate (20 g/100 m L) was incubated with chymotrypsin and glycerol at 37 degrees C. Different methionine methyl-ester concentrations, pHs, and time were tested. Amino ac id composition and functional properties of ultrafiltrated fractions (FI>10 , 10>FII>3, and 3>FII>1 kDa) were evaluated. Optimum hydrolysis conditions were 12 h and 50 degrees C, and those of synthesis were 0.07585 g Met/g, pH 7, and 3 h, binding 2.2% to 5% methionine. Fractions under 10 kDa presente d 100% solubility and the best clarity. High-methionine fractions had highe r foam volume, lower emulsifying capacity and hydrophobicity. Modified hydr olysates have a potential for use in soluble high nutritional products.