title: Quantitative structure-activity relationship study of bitter di- and tri-peptides including relationship with angiotensin I-converting enzyme inhibitory activity.
abstract: Bitterness represents a major challenge in industrial application of food protein hydrolysates or bioactive peptides and is a major factor that controls the flavor of formulated therapeutic products. The aim of this work was to apply quantitative structure-activity relationship modeling as a tool to determine the type and position of amino acids that contribute to bitterness of di- and tri-peptides. Datasets of bitter di- and tri-peptides were constructed using values from available literature, followed by modeling using partial least square (PLS) regression based on the three z-scores of 20 coded amino acids. Prediction models were validated using cross-validation and permutation tests. Results showed that a single-component model could explain 52 and 50% of the Y variance (bitterness threshold) of bitter di- and tri-peptides, respectively. Using PLS regression coefficients, it was determined that hydrophobic amino acids at the carboxyl-terminus and bulky amino acid residues adjacent to the carboxyl terminal are the major determinants of the intensity of bitterness of di- and tri-peptides. However, there was no significant (p > 0.05) correlation between bitterness of di- and tri-peptides and their angiotensin I-converting enzyme-inhibitory properties.
authors.affiliation: Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wu
authors.forename: Rotimi E
authors.initials: RE
authors.lastname: Aluko
mesh_terms: D000595:Amino Acid Sequence; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D016208:Databases, Factual; D004151:Dipeptides / Q000737:chemistry / Q000494:pharmacology; D005421:Flavoring Agents / Q000737:chemistry; D006801:Humans; D016018:Least-Squares Analysis; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D021281:Quantitative Structure-Activity Relationship; D013649:Taste
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004151:Dipeptides; D005421:Flavoring Agents; D009842:Oligopeptides; D007703:Peptidyl-Dipeptidase A