Quantitative Structure−Activity Relationship Study of Bitter Peptides

Abstract

A database consisting of 224 di- to tetradecapeptides and five amino acids was compiled to study quantitative structure-activity relationships of bitter peptides. Partial least-squares regression-1 analysis was conducted using the amino acid three z-scores and/or three parameters (total hydrophobicity, residue number, and log mass values) as X-variables and bitterness values (log 1/T where T is the bitterness threshold) as Y-variables. Using the three parameters only, significant models (p < 0.001) were obtained describing the entire data set as well as data subsets, except that comprised only of octa- to tetradecapeptides. For data sets comprising different peptide lengths, the models were improved by including the three z-scores at the N-terminal and C-terminal positions. Correlation coefficients for bitterness prediction of 48 dipeptides and 12 pentapeptides were 0.75 (RMSEP = 0.53) and 0.90 (RMSEP = 0.48), respectively. Bulky hydrophobic amino acids at the C terminus and bulky basic amino acids at the N terminus were highly correlated to bitterness.

Learnings from quantitative structure–activity relationship (QSAR) studies with respect to food protein-derived bioactive peptides: a review

“…25 The molecular mass, hydrophobicity, number of amino acid residues in the peptide together with the amino acid descriptors of the 3-z scale were incorporated in a PLSR. The previous physicochemical parameters had a higher inuence on the bitterness than the 3-z scale.…”

Specificity of Carboxypeptidases from Actinomucor elegans and Their Debittering Effect on Soybean Protein Hydrolysates

“…Nineteen N-substituted dipeptides and tripeptides were selected as substrates of the carboxypeptidases; they were regarded as bitter-tasting peptides [3,10,11,27].…”

“…However, the bitterness of this oligopeptide completely vanished when the Phe-Phe was substituted by Gly-Gly [10]. Kim and Eunice compiled a database consisting of 224 di-to tetradecapeptides and five amino acids in order to study the quantitative structure-activity relationship of bitter peptides [11]. They found that bulky hydrophobic acids at the C terminus and bulky basic amino acids at the N terminus were highly correlated to the bitterness [11].…”

Enzymatic hydrolysis of defatted mackerel protein with low bitter taste

“…The bitter taste of protein hydrolysates limits their utilization for human consumption. It is reported that the bitter taste of protein hydrolysates is mainly caused by hydrophobic amino acid residues and oligopeptides, and therefore the specificity of the enzyme used is decisive for the amount of such peptides produced during hydrolysis (Kim and Li-Chan, 2006;Gildberg et al, 2002). As shown in Fig.3c, flavourzyme hydrolysates, a fungal complex of exopeptidases and endoproteases used in the food functionality industry for extensive hydrolysis of proteins, display the least bitter taste in contrast to all the other enzymes.…”