Effect of temperature on nitrite and water diffusion in pork meat

•The effect of temperature on nitrite and water diffusion in pork meat was studied.•The nitrite and water mass transport was modelled by means of a diffusion model.•A good agreement was found between experimental kinetics and the diffusion model.•The effective diffusivity of nitrite and water increased as the temperature rose.•The activation energy for water loss was lower than the one for nitrite gain.

Nitrites are important food additives. The nitrite movement in meat is assumed to occur by means of a diffusion process. The objective of this study was to investigate the effect of temperature on nitrite and water diffusion mechanisms in meat samples during the curing of pork meat. For this purpose, cylinders of Semimembranosus muscle were salted with sodium nitrite (NaNO2) at 2 °C, 7 °C and 12 °C. Experimental curing and water loss kinetics were modelled by means of a diffusion model. As the curing time lengthened, the water content fell and the nitrite content increased. The values for the nitrite and water diffusion were estimated to be in the range of 4.58 · 10−12–1.02 · 10−12 m2/s and 5.96 · 10−9–9.82 · 10−9 m2/s respectively, and they increased as the temperature went up. The activation energy was 32.24 kJ/mol for water diffusion and 60.32 kJ/mol for nitrite diffusion.