59D-8 |
New preparation method of bitter-less peptides by novel protease D3 |
T. KODERA, M. Asano, and N. Nio. Food Research & Development Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, 210-8681, Japan Enzymatic hydrolysis is one of the ways of improving the functional properties of food protein ingredients. However, in most cases bitter peptides are generated by such treatment, whereby the product is not easily accepted as food ingredient. Several researchers have been applying a variety of peptidases for bitter peptide removal. These attempts usually end up with generation of so much free amino acids and tend to give a strong taste that it is utilized as seasonings, but not as peptide materials. Only a limited number of peptide materials are known that taste acceptable and donft have much amount of free amino acids. We have already reported a novel cysteine protease D3 from germinating soybean cotyledons. The substrate specificities of protease D3 is similar to cathepsin L and cathepsin B that it prefers a hydrophobic residue at the P2 site of the substrates. As a result, most of hydrophobic amino acid residues are not located at peptide terminals, (Itfs known that hydrophobic residues located at peptide terminals make peptides bitter). For the reasons mentioned above, we propose that protein hydrolyzate by protease D3 gives less bitterness than other enzymatic hydrolyzates. The objective of this study is to demonstrate the new method to provide bitter-less peptides by protease D3. We prepared soybean and casein hydrolyzates by protease D3, subtilisin, pepsin, trypsin and thermolysin. The bitterness of those hydrolyzates were evaluated by five trained panels by measuring a point of subjective equality (PSE). PSE showed the bitterness of protein hydrolyzate by protease D3 was significantly weaker than the hydrolyzates by other protease, and implied it was bland enough to intake orally as bitter-less peptide materials. These results suggest that protease D3 has a prominent character to provide bitter-less peptides, which can be applied to a variety of food products.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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