A multivariate insight into the organoleptic properties of porcine muscle by ultrasound-assisted brining: Protein oxidation, water state and microstructure

Ultrasound could accelerate mass transfer of brine into postmortem muscle, but the biochemical consequences and architecture of cured products require more validations. Herein, we comparatively evaluated the water holding capacity (WHC), instrumental color, textural parameters, protein oxidation and hydrolysis events, and microstructure of porcine biceps femoris (BF) after static brining (SB) and ultrasound-assisted brining (UAB, 350 W for 1 h). Results showed that brining significantly increased oxidative susceptibility of muscle proteins, improved WHC and color (L*, internal a* and surface b* values) as well as textural properties (hardness, springiness and chewiness) compared to the control samples (P < 0.05). SDS-PAGE pattern suggested that UAB led to a great loss of major myofilament components with generation of 15–20 kDa extracellular protein fragments. Additionally, microscopic observation proved that UAB samples rendered more compact and enhanced microfissures in tissue fibers than SB samples, implying an increasing course of salt diffusion. Multivariant analysis and chemometrics revealed that water-protein interactions should be the most important variables used to explain the textural changes of BF muscles upon ultrasound-assisted brining.