Flavour binding mechanism between a typical meat flavour compound (nonanal) and porcine myofibrillar proteins with consideration of conformational changes

Summary Flavour binding or release behaviour from the meat matrix is very important for its sensory properties. The interaction between flavour substance (nonanal) and myofibrillar proteins ( MP s) was investigated using protein fluorescence quenching at different temperatures. The results suggested that nonanal caused the fluorescence quenching mechanism of MP s combining dynamic and static quenching mode, and dynamic quenching played a dominant role. Nonanal mainly combined with tryptophan residues rather than tyrosine residues. The results of synchronous fluorescence spectra and circular dichroism ( CD ) revealed that the interaction between nonanal and MP s induced no significant conformational changes in MP s. The binding constant ( K ) and number of binding sites ( n ) (1.45–2.03) increased with temperature. The negative value of ∆G (−383.16 kJ mol −1 to −397.30 kJ mol −1 ) showed that the interaction of nonanal and MP s was spontaneous. The positive ∆H (180.18 kJ mol −1 , 181.48 kJ mol −1 ) and ∆S (696.17 J mol −1  K −1 , 688.32 J mol −1  K −1 ) indicated that the binding of nonanal to MP s driven by hydrophobic force.