Abstract: Fruit drying is a well known process mostly used for
preservation of fruits. Osmotic dehydration of apricot slices were
carried out in three different salt-sucrose concentrations and four
different temperatures. Also three different weight ratios of solution
to sample were conducted to one set of experiments. The dehydration
curves were constructed using Peleg-s model. Increasing the solution
volume increased the mass transfer rate and hence the solid gain
increased rapidly. Increasing the volume of osmotic media caused an
increase in overall mass transfer but a 'solution to sample' ratio of 5:1
gave the best product quality. The best temperature and concentration
that had a high water loss to solid gain ratio and an acceptable taste
were 40°C and 5%, respectively.
Abstract: Response surface methodology was used for
quantitative investigation of water and solids transfer during osmotic
dehydration of beetroot in aqueous solution of salt. Effects of
temperature (25 – 45oC), processing time (30–150 min), salt
concentration (5–25%, w/w) and solution to sample ratio (5:1 – 25:1)
on osmotic dehydration of beetroot were estimated. Quadratic
regression equations describing the effects of these factors on the
water loss and solids gain were developed. It was found that effects
of temperature and salt concentrations were more significant on the
water loss than the effects of processing time and solution to sample
ratio. As for solids gain processing time and salt concentration were
the most significant factors. The osmotic dehydration process was
optimized for water loss, solute gain, and weight reduction. The
optimum conditions were found to be: temperature – 35oC,
processing time – 90 min, salt concentration – 14.31% and solution
to sample ratio 8.5:1. At these optimum values, water loss, solid gain
and weight reduction were found to be 30.86 (g/100 g initial sample),
9.43 (g/100 g initial sample) and 21.43 (g/100 g initial sample)
respectively.
Abstract: Simultaneous effects of temperature, immersion time, salt concentration, sucrose concentration, pressure and convective dryer temperature on the combined osmotic dehydration - convective drying of edible button mushrooms were investigated. Experiments were designed according to Central Composite Design with six factors each at five different levels. Response Surface Methodology (RSM) was used to determine the optimum processing conditions that yield maximum water loss and rehydration ratio and minimum solid gain and shrinkage in osmotic-convective drying of edible button mushrooms. Applying surfaces profiler and contour plots optimum operation conditions were found to be temperature of 39 °C, immersion time of 164 min, salt concentration of 14%, sucrose concentration of 53%, pressure of 600 mbar and drying temperature of 40 °C. At these optimum conditions, water loss, solid gain, rehydration ratio and shrinkage were found to be 63.38 (g/100 g initial sample), 3.17 (g/100 g initial sample), 2.26 and 7.15%, respectively.
Abstract: Simultaneous effects of temperature, immersion time, salt concentration, sucrose concentration, pressure and convective dryer temperature on the combined osmotic dehydration - convective drying of edible button mushrooms were investigated. Experiments were designed according to Central Composite Design with six factors each at five different levels. Response Surface Methodology (RSM) was used to determine the optimum processing conditions that yield maximum water loss and rehydration ratio and minimum solid gain and shrinkage in osmotic-convective drying of edible button mushrooms. Applying surfaces profiler and contour plots optimum operation conditions were found to be temperature of 39 °C, immersion time of 164 min, salt concentration of 14%, sucrose concentration of 53%, pressure of 600 mbar and drying temperature of 40 °C. At these optimum conditions, water loss, solid gain, rehydration ratio and shrinkage were found to be 63.38 (g/100 g initial sample), 3.17 (g/100 g initial sample), 2.26 and 7.15%, respectively.
Abstract: In this study, the kinetics of osmotic dehydration of melons (Tille variety) in a ternary system followed by air-drying for preserving melons in the summer to be used in the winter were investigated. The effect of different osmotic solution concentrations 30, 40 and 50% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratios 1:4, 1:5 and 1:6 on the mass transfer kinetics during osmotic dehydration of melon in ternary solution namely sucrosesalt- water followed by air-drying were studied. The diffusivity of water during air-drying was enhanced after the fruit samples were immersed in the osmotic solution after 60 min. Samples non-treated and pre-treated during one hour in osmotic solutions with 60% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratio of 1:4 were dried in a hot air-dryer at 60oC (2 m/s) until equilibrium was achieved.