Effect of proteases on groundnut proteins (Arachis hypogaea L.)

Abstract

AbstractThe total proteins of Spanish Improved, TMV‐2 and DH‐3‐30 varieties were extracted and hydrolysed with two group specific enzymes alpha‐chymotrypsin and trypsin and a less specific enzyme, pepsin. Compared to casein, the proteins were highly resistant to hydrolysis by the group specific enzymes. However, the variety TMV‐2 was more susceptible to proteolysis than the other two varieties. While the ratio and extend of hydrolysis for pepsin was same in all the varieties they were different for alpha‐chymotrypsin. Nitrogen solubility profile of the meals in water, 1 M NaCl and 2% sodium hexametaphosphate solutions did not show any marked difference. Gel filtration, DEAE‐Cellulose chromatography, analytical ultracentrifugation and polyacrylamide gel electrophoretic patterns of the proteins did not indicate any major differences. However, the relative proportions of different fractions differed among the varieties. Gel filtration indicated that Spanish Improved variety contain higher amounts of conarachins (15%). Such quantitative differences of the various fractions may be responsible for the observed difference in the resistance to hydrolysis by the proteolytic enzymes.