Osmotic Dehydration of Yacon Using Glycerol and Sorbitol as Solutes: Water Effective Diffusivity Evaluation

Abstract

Osmotic dehydration of yacon (Smallanthus sonchifolius) was carried out in varying temperatures (30 and 50°C) and glycerol or sorbitol concentration (30, 50, and 70 %). The solution of Fick's law for unsteady state mass transfer in a plane sheet configuration was used to calculate the effective diffusivities of water. Peleg's model was used to predict the equilibrium condition, which was shown to be appropriate for water loss and solute uptake. It was found to have two rate periods of dehydration. For the above conditions of osmotic dehydration, the effective diffusivity of water was found to be in the range of 5.82±0.68×10 −10 to 2.15±0.61× 10 −10 m 2 /s in first period and 1.60±0.28×10 −10 to 1.29± 0.24×10 −10 m 2 /s in second period for glycerol tests and, for sorbitol, was 3.82±0.17×10 −10 to 1.54±0.50×10 −10 m 2 /s for the first period and 1.73±0.04×10 −10 to 1.33±0.06×10 −10 m 2 / s for the second. The greatest reduction in water activity was achieved when 70 % of glycerol was used at 50°C (final a w 0.704±0.010). The treatments with 70 % of solution concentration at 30°C were repeated, and by adding 20 g/L of calcium lactate in the osmotic solution, it resulted in higher calcium content, strengthening the cell wall for both solutes. Microstructure of the yacon samples (fresh, blanched, and in different conditions of osmotic dehydration) was examined by scanning electron microscopy.

Evaluation and modelling of osmotic pre‐treatment of peach using alternative agents in a multiple‐component solution

“…fructo-oligosaccharides, galacto-oligosaccharides, flavonoids, phenolics and vitamins. [12][13][14][15][16][17][18][19] Through the selective and controllable incorporation into the food system obtained by OD treatment, it is possible to change the final nutritional and functional properties, achieving a specific formulation of the product while maintaining to a great extent its integrity.…”

Rehydration of osmotically pre-treated apple cubes dried by hot air, microwave, and freeze-drying

“…The osmotic agent most used in the OD of fruit is sucrose, because of its effectiveness, convenience, and desirable fl avour (LENART, 1996). Other solutes have been used in the osmotic process, such as sorbitol (CHAUHAN et al, 2011;RODRÍGUEZ et al, 2013;BROCHIER et al, 2014). Sorbitol is a prebiotic with proven health benefi ts (CHAUHAN et al, 2011;PATEL & GOYAL, 2012;CHANDRA & KUMARI, 2015).…”

Changes in liquid phase and mechanical properties during osmodehydrofreezing of papaya (carica papaya L.)

“…Similar behavior was observed in papaya with osmotic pretreatment at 65°Brix [15], and in other fruits like apple and pear [8], melon [14] and strawberry [7]. It is possible that with increasing storage time in freezing a change arises in the size, number and shape of ice crystals (ice recrystallization), causing the output of the liquid phase or loss of the capacity for water retention of the fruit cell [26,27].…”

“…Treatments with higher concentration of osmotic solution (55°Brix) showed lower moisture content than those treated at 45°Brix for the same dehydration time. This is because the OS with higher concentration has greater driving force or greater osmotic pressure gradient between the solution of the environment and food, which had achieved an acceleration of the dehydration kinetics [26].…”