Sugar or salt solutions are used to reduce the moisture content of foods before actual drying process.
Mild heat treatment after osmotic dehydration favours colour and flavour retention resulting in the product having superior organoleptic characteristics.
It also increases resistance to heat treatment, prevents enzymatic browning and inhibits activities of polyphenol oxidase.
Osmotic dehydration depends on: Water removal is based on the natural and non-destructive phenomenon of osmosis across cell membranes.
Since the cell membrane responsible for osmotic transport is not perfectly selective, solutes present in the cells (organic acids, reducing sugars, minerals, flavors and pigment compounds) can also be leaked into the osmotic solution, which affects the organoleptic and nutritional characteristics of the product.