Ultrasound-induced structural remodeling modulates salt-moisture coupled mass transfer and quality improvement during low-temperature braising of chicken breast: A multiscale analysis.

This study established a multiscale analytical framework to systematically investigate the mass transfer behavior of NaCl and moisture in chicken breast during ultrasonic-assisted low-temperature braising, as well as the regulatory mechanisms impacting quality evolution. Kinetic analysis demonstrated that ultrasound treatment significantly enhanced NaCl migration during processing, with the NaCl content reaching 1.83 g/100 g after treatment at 600 W for 150 min, representing a 29.8% increase compared with the control. The effective diffusion coefficient (Deff) calculated using Fick's second law increased to (5.69-6.37) × 10-9 m2/s under ultrasonic treatments. Low-field magnetic resonance imaging (LF-MRI) combined with image binarization revealed that ultrasound promoted the penetration of NaCl toward the sample center and improved moisture distribution. The proportion of immobilized water (P21) reached 96.39% at 450 W for 30 min. At the microscopic level, haematoxylin-eosin (HE) staining, and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) analyses revealed that ultrasound treatment generated microchannels, reducing mass transfer resistance. The resulting spongy structure enhanced moisture retention capacity. COMSOL Multiphysics simulations visualized the spatial and temporal evolution of NaCl and moisture migration, with strong agreement between predicted and experimental values (R2 > 0.97). Moderate ultrasonic treatment (300-450 W) achieved a favorable balance between enhanced salt uptake and reduced moisture loss, resulting in improved texture properties, including decreased shear force and hardness. The study established a correlation framework of "ultrasound transfer-structure response-quality improvement", providing insights into the precise control and quality improvement of novel thermally processed meat products using ultrasound treatment.