Studies on Flavoring Substances

Part II. Taste of enzymatic proteolysates and preparation of a palatable proteolysate for flavoring substance

Abstract

Several kinds of proteins such as milk casein, soybean protein and beef protein, were hydrolysed by the commercially available protease preparations, thereafter, the taste of the hydrolysate and the degree of hydrolysis were examined. Organoleptic studies showed that the hydrolysates from milk casein, soybean protein and wheat gluten had strong bitter taste, while those of gelatin, bonito and beef protein not so bitter.
Generally, the hydrolysates obtained by treating the proteins with enzymes, which have strong endopetidase activity and weak exopeptidase activity, were evaluated to have strong bitter taste.
By treating with peptidase from Streptomyces peptidofaciens, which has aminopeptidase and carboxy-peptidase activity, the bitter taste of the hydrolysates were removed or decreased and a palatable taste appeared.
It is presumed that the debittering action of the peptidase can be attributed to the hydrolysis of N-terminal leucine and phenylalanine or C-terminal leucine, phenylalanine, valine, lysine and tyrosine of the bitter peptides.
72.5% of peptide bonds of milk casein and 42.5% of soybean protein could be hydrolysed by a combination use of alkaline proteinase Tasinase-B and the peptidase.
A method was suggested to prepare a palatable proteolysate for flavoring substance by the com- bination use of the endopeptidase and the exopeptidase.