Effects of ultrafine comminution treatment on gelling properties of myofibrillar proteins from chicken breast

Abstract

Effects of ultrafine comminution treatment on gelling properties of myofibrillar proteins (MPs) from chicken breast were investigated. The MPs were extracted and treated by four comminution processes (mortar P0, planetary ball P6, rotation P14, and oscillatory ball P23). Particle size, texture, secondary structure, water distribution, and microstructure of MP powders and MP gels were measured via dynamic light scattering, texture analyzer, Fourier transform infrared spectroscopy, Raman spectroscopy, low field-nuclear magnetic resonance, and scanning electron microscopy. Results showed that, compared with conventional mortar grinding P0 (non-ultrafine comminution), the particle size of MPs was significantly reduced from 2396.28 ± 1.95 nm to 1036.35 ± 0.71 nm after P6 milling. The hardness and elasticity of MP gels were likewise remarkably enhanced by ultrafine comminution processes (P6, P14, and P23). Comparing P6 with P0, the content of α-helix decreased from 45.23 ± 0.07% to 34.08 ± 0.06%, while that of β-fold increased from 27.79 ± 0.41% to 37.52 ± 0.03%, free water increased from 0.30 ± 0.05% to 5.44 ± 0.02%, and immobilized water decreased from 98.71 ± 1.55% to 93.27 ± 0.77%. Furthermore, the microstructure of MP gels was compact and smooth due to enhanced hydrophobicity of MPs. In conclusion, P6 milling was more effective than P14 and P23 milling in protein gelation on the basis of particle size, protein secondary structure and water distribution, as well as exposure of hydrophobic groups.