Production and Sensory Characterization of a Bitter Peptide from β-Casein

Peptide β-casein fragment 193-209 (β-CN f193-209) was isolated and purified for detailed sensory analysis in different matrices. The purity of the peptide was >98%. The mass of the peptide was 1882.51 Da, which coincided with the expected mass of β-CN f193-209. N-Terminal analysis confirmed that the peptide started at residue 193 on the published sequence of β-casein. Detection thresholds were 0.03, 0.06, and 0.63% (w/w) for water, milk, and cheese, respectively. Descriptive sensory analysis confirmed that the peptide exhibited a bitter taste, which increased with increasing concentrations, with minimal other flavors or tastes detected. The β-CN f193-209 can contribute to bitterness in cheeses. Keywords: Caseins; peptide; bitter taste; caffeine; quinine sulfate; sensory threshold analysis; descriptive sensory analysis