Debittering effect of Monascus carboxypeptidase during the hydrolysis of soybean protein

Abstract

The actions of pepsin and the admixture of pepsin and Monascus pilosus carboxypeptidase 1 (MpiCP-1) on the hydrolysis of soybean protein were studied. The results showed that the pepsin hydrolyzate of soybean protein was much more bitter and contained relatively smaller amounts of total free amino acids than the hydrolyzate obtained with the admixture of pepsin and MpiCP-1. In addition, hydrophilic and hydrophobic amino acids were present in almost equal proportions in the pepsin hydrolyzate, while mainly hydrophobic amino acids made up the hydrolyzate obtained with the admixture of pepsin and MpiCP-1. These results suggest that MpiCP-1 suppresses and reverses the development of the bitterness taste that results from the pepsin hydrolysis of soybean protein by releasing mainly hydrophobic amino acids from the C-termini of the bitter components.

Fermented Tofu, Tofuyo

“…Thus, carboxypeptidases from the genus Monascus are concluded to play an important role in the formation of taste-associated compounds (amino acids) from soybean protein during the maturation of tofuyo. The action of pepsin and the admixture of pepsin and carboxypeptidase from the genus Monascus on the hydrolysis of soybean protein were studied (Liu & Yasuda, 2005). The results showed that the pepsin hydrolysates of soybean protein were much more bitter and contained relatively smaller amounts of total free amino acids than the hydrolysates obtained with the admixture of pepsin and the enzyme.…”

Debittering effect of Actinomucor elegans peptidases on soybean protein hydrolysates

“…Fungal carboxypeptidases, such as Aspergillus acid carboxypeptidase [22][23][24][25] and Mucor racemosus carboxypeptidase [5], are usually a serine carboxypeptidase with a broad speciWcity. Arai et al [3] reported the bitterness of peptides from soybean protein hydrolysates [15] found that Monascus pilosus carboxypeptidase (MpiCP-1) could suppress and reverse the development of the bitterness taste that resulted from the pepsin hydrolysis of soybean protein by releasing mainly the hydrophobic amino acids from the C-terminal of the bitter components. Regardless of the new Wndings of the diVerent peptidase activities of the A. elegans exact, further investigation for puriWcation and speciWcity determination of the A. elegans carboxypeptidase is needed and conducted in our labs.…”

Proteolysis characteristics of Actinomucor elegans and Rhizopus oligosporus extracellular proteases under acidic conditions

“…Enzymatic hydrolysis of soybean protein can improve and expand the range of functional properties, including solubility, heat stability and resistance to precipitation in acidic environments, without diminishing the nutritional value of the products (Saha & Hayashi, 2001;Sun, 2011). However, the usual bitterness of the hydrolysates, which is due mainly to hydrophobic amino acids at the N or C terminus of the polypeptide chains (Arai et al, 1970;Yeom et al, 1994;Raksakulthai & Haard, 2003;Liu & Yasuda, 2005), is a major limitation of their use and several methods for reducing the bitterness of protein hydrolysates have been used (Nishiwaki et al, 2002;FitzGerald & O'Cuinn, 2006;Kodera et al, 2006;Damle et al, 2010). Exopeptidases, especially the carboxypeptidases produced by fungi, such as Aspergillus sp.…”