Freeze/Thaw Effects on Mass Transfer Rates during Osmotic Dehydration

Abstract

A model fruit system (apple slices) was studied during osmotic preconcentration in concentrated solutions of corn syrup solids. The effect of freeze/thawing on water removal and solid uptake rates during complimentary osmotic dehydration was examined. Product response to freeze/thawing after partial osmotic dehydration was also explored. Osmotically preconcentrated, frozen/thawed samples did not exhibit a significant change in rate of water loss during complimentary osmotic dehydration. They had sharply higher sugar gain rates compared to controls. The duration of osmotic preconcentration had a significant effect on freeze/thaw induced exudation losses.

Optimization of Osmotic Dehydration Process of Pineapple by Response Surface Methodology

“…Further the interaction X 1 -X 2 and X 1 -X 3 has positive effect and X 2 -X 3 has negative effect on solid gain during osmotic dehydration. The experimental values for water loss & solid gain under different treatment conditions showed that water removal was always higher than the osmotic agent uptake, in agreement with the results of other workers [10].…”

“…Further, the interaction X 1 -X 2 and X 1 -X 3 has positive effect and X 2 -X 3 has negative effect on water loss. This is due to rise on fruit membrane permeability caused by higher temperatures promotes swelling & plasticization of cell membrane, favouring mass transfer [10,11]. Higher temperatures promote faster water loss through swelling and plasticizing of cell membranes as well as the better water transfer characteristics on the product surface due to lower viscosity of the osmotic medium [12,13].…”

Infusion of fruits with nutraceuticals and health regulatory components for enhanced functionality

“…High molecular weight osmotic agents (e.g. low dextrose equivalent corn syrup solids) could decrease the solute intake during osmosis (Hughes, Chichester, & Sterling, 1958;Lazarides & Mavroudis, 1995). As well, this process may cause leaching of natural solute from the food leading to negative values of net solid gain.…”

A study of the mass transfer in osmotic dehydration of coated potato cubes

“…Osmotic dehydration has been widely used as a pretreatment step in food drying processes to improve the quality of food by maintaining its integrity (Ponting, 1973;Torreggiani, 1993). Osmotic dehydration system has drawn increased attention due to the following advantages: (1) mild process temperatures do not affect the semi-permeable characteristics of cell membranes, (2) moderate temperatures can enhance the retention of color and flavor, (3) osmotic dehydration can reduce the overall energy requirement for further drying processes of the product such as hot-air drying and freeze drying (Lazarides & Mavroudis, 1995;Lenart & Lewicki, 1988;Ponting, 1973).…”