Influence of ultrasonic parameters on osmotic dehydration of pork loin: Effects on structure, composition, and mass transfer

The intensification of food processing using ultrasound (HIUS) has gained relevance at the industrial level due to its ability to improve process efficiency without compromising product quality. This study investigated the influence of certain HIUS parameters on the osmotic dehydration (OD) of pork loin, evaluating its impact on mass transfer, physicochemical properties, structure, and thermal behavior. Conventional OD (immersion) and with HIUS assistance were performed, varying the amplitude and duty cycle (UA1: 50 % - 0.5; UA2: 50 % - 0.8; UA3: 90 % - 0.5; and UA4: 90 % - 0.8). The results revealed that the UA3 conditions significantly improved water loss, solute incorporation, and the diffusion coefficients of water (0.33 ± 0.06 × 10^-10 m²/s) and solids (2.36 ± 0.01 × 10^-10 m²/s), thus optimizing process efficiency. At the compositional level, UA3 achieved greater dehydration (73.4 ± 1.0 %) without compromising protein content or water holding capacity. A substantial reduction in a_w was observed, going from 0.98 ± 0.03 to 0.91 ± 0.00, a key factor for OD. Scanning electron microscopy revealed a more porous microstructure with defined channels, which is associated with improved mass transfer. Thermal analysis confirmed the decrease in free water and the increase in incorporated solutes, reflected in lower enthalpies and melting temperatures. Regarding certain quality aspects, color remained stable in most treatments, and the reduction in shear force in UA2 and UA4 suggests an improvement in product tenderness. Taken together, these findings position HIUS as a promising technology for enhancing meat preservation, enabling faster and more efficient processes.