Mass transfer kinetics in brining pork compared to pure myofibrillar protein

Salt diffusion and water migration are key to pork curing, yet the applicability of pure myofibrillar protein (MP) models to real meat systems remains unclear. This study cured fresh pork loin at 40, 80, 120, and 160 g kg^-1 NaCl, revealed salt-dependent regulatory mechanisms, and evaluated the applicability of the model.

Salt concentration exerted dual regulatory effects on curing mass transfer. Moderate salting at 80 g kg^-1 provided the most uniform salt distribution, with an internal-to-external salt ratio of 1.10. Low salt caused insufficient driving force and osmotic lag, and high salt induced severe protein denaturation and uneven salt distribution. A spatiotemporal diffusion equation D(x,t) = A x^a t^b was established, with the best fit observed in the 120 g kg^-1 group. Pronounced differences existed between real pork and pure protein systems. Structural heterogeneity induced larger surface concentration gradients and higher internal apparent diffusion coefficients in pork, with a greater proportion of water associated with less-mobile states and a higher estimated contribution of hydrophobic interactions under high salt, in contrast to the increased estimated contribution of ionic interactions in the MP system. Salt concentration regulated water migration and microstructure through osmotic effects. Low salt promoted myofibrillar swelling, whereas high salt induced dehydration and contraction, potentially increasing surface mass-transfer resistance.

Pure MP models may not fully represent mass transfer in real pork systems, highlighting the potential mechanisms underlying their differences and providing theoretical support for low-salt curing. © 2026 Society of Chemical Industry.