The effects of Sucrose/NaCl/Time interactions on the osmotic dehydration of banana slices

Efeitos de interações de Sacarose/NaCl/Tempo na desidratação osmótica de fatias de banana

Abstract

The objective of this work was to study the mass transfer kinetics during the osmotic dehydration of banana slices in an osmotic solution prepared by combining sugar with salt. Two levels of sucrose concentration (50 and 60 °Bx), three levels of NaCl content (0, 5% and 10% w/v) and four time levels (90, 180, 270 and 360 min) were applied according to the full factorial technique. The experiments were carried out with three replications and the means analyzed using response surface methodology (RSM). The experimental data revealed that the water loss increased with increase in time, sucrose and salt contents. According to the data obtained the minimum and maximum water losses observed were 9.0% (at 50 °Bx, 0% salt and 90 min) and 46.5% (at 60 °Bx, 10% salt and 360 min), respectively. Furthermore, a small portion of salt was found to reduce the solids gain while the sugar content and time increased it. The effects of all the parameters were significant for water loss, while only those of sucrose content, time and the interaction of salt with sucrose were significant for solids gain. Based on Fick’s second law, the effective diffusivity of water in banana slices was evaluated in the range from 5.67×10^-9 to 9.11×10^-9 m ²/s for the solutions studied.

Keywords:
Banana; Effective diffusivity; Osmotic dehydration; Response surface methodology; Statistical analysis; Mass transfer