Ultrasound-assisted low-sodium salt curing to modify the quality characteristics of beef for aging

Meat products for elderly people are high in sodium content and hardness. Thus, the aim of this study is to explore how ultrasound-assisted low-sodium salting improves meat quality and determine the conditions that result in meat tenderness ideal for people aged 65-74 years. The ultrasound-assisted treatment of bovine hip muscle with non-sodium salt (CaCl₂ and C₆H₁₀CaO₆) was adopted, followed by sous vide (SV) cooking (65 ℃ for 8-12 h). Results showed that ultrasound-assisted low-sodium salt curing can considerably reduce the shear force and hardness of beef (P < 0.05), promote the diffusion of Na⁺ (P < 0.05), and increase water content (P < 0.05), consistent with the water mobility results of low-field nuclear magnetic resonance. The tenderized effects were examined by Raman spectroscopy, which showed that the ordered α-helix and β-fold contents of the meat proteins decreased, and disordered β-turn and random coil contents increased after heat treatment with ultrasound-assisted low-sodium salt curing. Scanning electron microscopy revealed that the degree of muscle fiber destruction by ultrasound-assisted low-sodium salt curing combined with heat treatment was higher than that observed after traditional cooking with high amounts of sodium. With regard to tenderness, beef marinated with ultrasound-assisted C₆H₁₀CaO₆ and subjected for 10 h was preferred by people aged 65-74 years. Ultrasound-assisted low-sodium salt curing can improvements on simultaneously reduce the sodium content and enhance the tenderness of meat products for elderly people, and provides an ultrasonic scheme for meat processing using non-sodium salt.