Isolation of Bitter Peptides from Tryptic Hydrolysate of Casein and their Chemical Structures

Abstract

Bitter peptides were isolated from the tryptic hydrolysate of casein. Fractionation and isolation were carried out using n-butanol extraction, acidic precipitation at pH 5.4, gel filtration with Sephadex G-25, ion exchange chromatography with Dowex 50 W and paper chromatography. Three kinds of bitter peptides were purified. The primary structures of these peptides were proposed as follows; BP-I, Gly-Pro-Phe-Pro-Val-Ileu; BP-II, Phe-Phe-Val-Ala-Pro-Phe-Pro-Glu-Val-Phe-Gly-Lys; BP-III, Phe-Ala-Leu-Pro-Gln-Tyr-Leu-Lys. These peptides were very bitter in a 0.1% solution. L-Tyrosine, L-phenylalanine and their derivatives were also tasted. The importance of the position of bitter amino acids in the peptide in the development and strengthening of its bitter taste is discussed. © 1970, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.