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.

本研究旨在探讨肌原纤维蛋白（MP）、肌浆蛋白（SP）和胶原蛋白（CO）在加热过程中构象变化及热降解对其与香气化合物结合能力的影响。通过SDS-PAGE、高效液相色谱（HPLC）和液相色谱-质谱联用（LC-MS/MS）技术，观察到蛋白质热降解产生的肽和游离氨基酸的总浓度持续上升。随着时间推移，蛋白质的表面疏水性、总巯基含量、粒径和二级结构含量发生了显著变化。此外，采用气相色谱-质谱（GC-MS）技术测定了蛋白质的香气结合能力。结果显示，在加热5或10分钟时，由于蛋白质展开和降解产物的积累，结合能力增强。然而，随着加热时间的延长，蛋白质聚集导致结合能力下降。值得注意的是，所有蛋白质对（E）-2-辛醛、（E,E）-2,4-癸二烯醛、2-甲基-3-呋喃硫醇和二甲基三硫均表现出强烈的亲和力。MP和SP的结合能力相似，但与CO相比存在显著差异，后者对己醛、（E）-2-辛醛、（E,E）-2,4-癸二烯醛和二甲基三硫的结合能力低于MP和SP。