Effect of microwave and conduction heating on the adsorption ability of myofibrillar protein to pyrazine flavor compounds

In order to clarify the modulation of microwave and conduction heating on the aroma release and adsorption of meat, the effect of different myofibrillar proteins (MP) on the release ability of pyrazines (2-methylpyrazine, 2,5-dimethylpyrazine, and 2,3,5-trimethylpyrazine) was investigated. The adsorption ability, hydrophobicity of MP, and thermodynamic parameters were analyzed. Conduction heating by water bath exhibited stronger adsorption ability of MP for 2-methylpyrazine (17.17 ± 2.27%) than that of microwave, followed by 2,3,5-trimethylpyrazine (11.50 ± 0.91%) and 2,5-dimethylpyrazine (8.63 ± 5.24%), which accounted for the structures of pyrazines. Water bath heating promoted protein unfolding leading to increased exposure of hydrophobic regions thereby enhancing binding affinity with pyrazine flavor compounds. Furthermore, fluorescence quenching ability was enhanced with increasing substituents on pyrazine flavor compounds. The hydrophobic interaction between 2,5-dimethylpyrazine and MP was dominant in both heat treatments. The interactions of conduction-heated MP with 2-methylpyrazine and 2,3,5-trimethylpyrazine predominantly involved hydrophobic forces, whereas interactions with microwave-heated proteins were primarily driven by van der Waals forces and hydrogen bonding effects. The results obtained from this study provide valuable theoretical insights into understanding the differences in the flavor release of meat product resulting from microwave versus water bath heating.