peptide bond formed between the carboxyl group of the phenylalanine
and the amine group of the tryptophan means the apolar
rings of both amino acids are at opposing ends of the molecule
available to participate in hydrophobic interactions. Liu and Caffrey
(2006) reported a peptide comprising multiple tryptophan
amino acids to have a higher equilibrium constant between an
aqueous and lipid phase than a single tryptophan amino acid. In
the present study the pentapeptide was by far the most hydrophobic
molecule examined with a k0 of 21.4 and correspondingly
had the highest equilibrium constant. This suggests that not only
do hydrophobic interactions create an affinity between riboflavin,
amino acids, peptides and the microbead but the more hydrophobic
the compound the greater the affinity. Hydrophobic attractions
have been reported to influence the interaction between peptides
and whey proteins (Creusot, Gruppen, Van Koningsveld, De Kruif,
& Voragen, 2006). The relationship between the level of hydrophobicity
and the equilibrium constant was further examined in
Section 3.5.