Physicochemical and structural changes in myofibrillar proteins from porcine longissimus dorsi subjected to microwave combined with air convection thawing treatment

Abstract

The effect of microwave combined with air convection thawing (MAT) on the properties and tertiary structure of myofibrillar proteins (MPs) from porcine longissimus dorsi muscle was investigated and compared with single treatments (air thawing, microwave thawing) and fresh meat (FM). Among the thawing treatments, the carbonyl content, dityrosine content, and surface hydrophobicity of MPs in MAT were the lowest, whereas the total sulfhydryl content, water-holding capacity, and Ca²⁺-ATPase activity were the highest, suggesting that MAT retained MPs properties better. MAT possessed a more stable tertiary structure and exhibited slight changes in MPs aggregation and degradation. There was an insignificant difference (P > 0.05) in the immobilized water and free water between the MAT samples and FM, indicating a tighter interaction between water and muscle protein in MAT. Thus, MAT could retain the physicochemical and structural properties of MPs, which provided a combination of thawing treatments for application in meat industry.

Keywords: Microwave combined with air convection thawing; Moisture migration; Myofibrillar proteins; Protein properties; Tertiary structure.