Mass transfer modeling of equilibrium and dynamic periods during osmotic dehydration of radish in NaCl solutions

Comparison of diffusion models for description of osmotic dehydration of radish slices dipped in brine

“…In the literature, diffusion models with boundary condition of the first kind are mostly used to explain convective drying (SILVA et al, 2009;DA SILVA et al, 2012;SILVA et al, 2012;DOYMAZ, 2013) and also osmotic dehydration of agricultural products (QUEIROZ et al, 2010;SOUZA SILVA et al, 2011;MERCALI et al, 2011;HERMAN-LARA et al, 2013). Overall, the boundary condition is derived from the agitation condition of the environment within which a particular product is immersed.…”

“…As it is known, moderate temperatures can enhance color and flavor retention (KHIN et al, 2006), as well as providing least thermal degradation of nutrients (JAIN et al, 2011). The experiments were conducted as in HERMAN-LARA et al (2013), in which water loss and sodium chloride gain were determined by gravimetric method (precision of 0.001 g). At each sampling, the slices were rinsed under distilled water and gently wiped with paper towel to remove outer moisture.…”

“…As for humans, its nutritional value includes carbohydrates, sugars, fibers, fat and protein, aside from vitamins B1-B6, B9 and C and calcium, iron and magnesium, among others. This way, several studies on radish are found in the literature because of such nutritional importance (COOGAN and WILLS, 2002;HERMAN-LARA et al, 2013;GOYENECHE et al, 2013), and some of these researches will be highlighted hereinafter.…”

“…Agríc., Jaboticabal, v.35, n.5, p.894-904, set./out. 2015 895 this sense, HERMAN-LARA et al (2013) investigated equilibrium and dynamic mass transfer properties of water and solute during osmotic dehydration of radish slices dipped in sodium chloride solutions at varied concentrations and temperatures. Then, these authors used one-dimensional analytical model for mass transfer based on Fick's second law to describe water loss and solute gain curves.…”

“…According to these authors, their results may be applied to determine a set of conditions (process time, brine concentration and process temperature) yielding an osmodehydrated radish product within given specifications. The diffusion model used by HERMAN-LARA et al (2013) to describe the mass transfers within the cylindrical pieces of radish involves, mainly, two simplifications: (1) the slices were considered as infinite slabs; (2) the boundary condition of diffusion equation is of first order. As an advantage, this model can determine mass diffusivities by means of simple regressions.…”