Ultrasonic treatment treated sea bass myofibrillar proteins in low-salt solution: Emphasizing the changes on conformation structure, oxidation sites, and emulsifying properties

• Published in: Food chemistry 2024-03, Vol.435, p.137564-137564, Article 137564
• Main Authors: Lan, Meijuan, Li, Tongshuai, Li, Lin, Wang, Shaoyun, Chen, Juncheng, Yang, Tangyu, Li, Zhiru, Yang, Yipeng, Zhang, Xia, Li, Bing
• Format: Article
• Language: English
• Subjects: bass; circular dichroism spectroscopy; disulfides; Emulsifying properties; fluorescence; fluorescence emission spectroscopy; food chemistry; hydrophobicity; Low-salt solution; Myofibrillar protein; myosin heavy chains; Oxidation; particle size; polyacrylamide gel electrophoresis; solubility; turbidity; Ultrasonic treatment; ultrasonics
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.137564

[Display omitted] •Ultrasonic increased the solubility of myofibrillar protein in low-salt solution.•The α-helix content of myofibrillar protein increased after ultrasonic treatment.•Amino acids at myosin heavy chain were easier to be oxidized than other amino acids.•Monooxidation was the major modifications identified.•Emulsion stabilized by 800 W treated-myofibrillar protein was uniform and stable. The physiochemical properties, structure characteristics, oxidation, and emulsifying properties of myofibrillar proteins (MPs) in low salt solution after treated by the ultrasound were investigated. The solubility, mean diameters, sulfhydryl content, and carbonyl contents of MPs after ultrasonic treatment increased, while the turbidity decreased. The surface hydrophobicity of MPs with 200 W–600 W treatment increased, but decreased at 800 W treatment. The circular dichroism analysis revealed that α-helix content increased, while β-sheet and random coil content decreased after ultrasonic treatment. Fluorescence spectroscopy indicated the fluorescence intensities of MPs were increased after ultrasonic treatment. SDS-PAGE results showed more protein polymers due to myosin heavy chain (MHC) aggregation via disulfide bonds. Based on LC-MS/MS result, the myosin heavy chain was susceptible to oxidation, with monooxidation being the main oxidative modification. Finally, the emulsions stabilized by ultrasonically treated MPs, especially those treated at 800 W, exhibited decreased particle size, improved uniformity, and enhanced stability.