Mechanism of Digestion of Bitter Peptides from Soybean Protein by Wheat Carboxypeptidase

Abstract

A bitter peptide fraction from the peptic hydrolysates of soybean protein was treated with crystalline wheat carboxypeptidase. The bitterness of the bitter fraction lessened with an increase in free amino acids and finally disappeared. The enzymatic hydrolysate obtained from the digest of the bitter peptide fraction by wheat carboxypeptidase was chromatographed on Sephadex G-15. Amino acid compositions of each eluate fraction were determined by an amino acid analyzer. When the release percentage of total free amino acids was approximately 27%, those of hydrophobic amino acids with a Δf value (cal/mo1)>1600 were 27-63% except for proline, and amino acids with a Δf value<1600 had a tendency to be released less than hydrophobic amino acids. The wheat carboxypeptidase seems to have an ability to eliminate bitter taste in enzymatic hydrolysate by releasing hydrophobic amino acids from bitter peptides.