Effect of agitation and antagonism between sucrose and sodium chloride on mass transfer during osmo-dehydration in plant materials

Abstract

Osmotic dehydration studies on two varieties of apple (Golden Delicious and Cox), potato and banana found that the amount and rate of water loss occurred in the following descending order: Golden Delicious > Cox > potato > banana. However, minimal improvement on the mass transfer in the amount of water loss and solids gain and their corresponding rates was observed in the presence of sodium chloride and agitation of the osmotic solution especially for the first 30 minutes of osmotic dehydration for all the plant materials. Concentration of the osmotic solution and immersion time of samples in the osmotic solution had a significant effect on amount and rate of water loss from all commodities. The mass transfer in all the studied commodities depicted two distinct phases for the amount of water loss and rate of water loss. A corresponding uptake of solids from the osmotic solution occurred, the rate been greatest over the first 30 minutes, before declining significantly thereafter. For the mass transfer the rate of water loss was 3 - 8 times higher than solids gain