Binding of Selected Aroma Compounds to Myofibrillar Protein, Sarcoplasmic Protein, and Collagen during Thermal Treatment: Role of Conformational Changes and Degradation of Proteins

To investigate the effects of conformational changes
and thermal
degradation of myofibrillar protein (MP), sarcoplasmic protein (SP),
and collagen (CO) on the binding ability for aroma compounds during
heating. Using SDS-PAGE, HPLC, and LC–MS/MS, a consistent rise
in the total concentration of peptides and free amino acids formed
by the thermal degradation of proteins was observed. The surface hydrophobicity,
total sulfhydryl content, particle size, and secondary structure content
of proteins changed significantly over time. Furthermore, the aroma
binding ability of proteins was determined by gas chromatography–mass
spectrometry. The results revealed an increase in binding ability
during 5 or 10 min of heating due to protein unfolding and the accumulation
of degradation products. However, the binding ability decreased due
to protein aggregation with prolonged heating. Notably, all proteins
exhibited strong affinity toward (E)-2-octenal, (E,E)-2,4-decadienal, 2-methyl-3-furanthiol,
and dimethyl trisulfide. The binding ability of MP and SP was similar
but differed significantly from that of CO, which had lower binding
ability for hexanal, (E)-2-octenal, (E,E)-2,4-decadienal, and dimethyl trisulfide compared
to MP and SP.