Transport of sodium chloride and water in Romano cheese slices during brining

Abstract

The transport of NaCl into cheese appears to occur by a mutual diffusion process; however, water appears to be lost by a combination of mutual diffusion and by osmosis, the osmotic effect being more pronounced as the surface area to volume ratio increases, due to the higher salt uptake. The salt molality (m NaCl) in cheese slices was proportional to the square root of the brining period (√t); a rate parameter, K (moles kg − 1 ) min − 0·5 ), was defined as the slope of the m NaCl√t plots. The rate parameter, K, was linearly related to the surface area to volume ratio of the cheese slices by the equation: K= (SA/V+1·2) 34·70 where; SA = surface area and V = volume of the cheese slice. The value of K was a function of brine concentration; K = 0·009 (% NaCl in brine) + 0·029. K increased with increasing temperature to an extent dependent on slice thickness. Cheese slices are useful models in certain cases, e.g. absorption of expensive species (enzymes, flavours, amino acids, peptides) and studies of the influence of cheese geometry on salt and water changes during brining.