Influence of sodium replacement and vacuum pulse on the osmotic dehydration of eggplant slices

•The osmotic dehydration of eggplant slices was studied.•The effects of the replacement of NaCl and the vacuum application was evaluated.•The vacuum pulse aid to decrease the moisture content and the water activity in OD.•Changes in the properties of the osmodehydrated eggplant were observed.•The feasibility of the PVOD and the use of KCl and CaCl2 was achieved.

Partial replacement of sodium chloride by potassium and calcium chlorides has been proposed as a strategy for reducing the sodium content of osmodehydrated eggplant. The influence of sodium substitutes and vacuum application (VA) on mass transfer parameters and chemical, mechanical and optical properties were investigated. Kinetics of water loss, solid gain and water activity were performed and fitted by the model of Barbosa Junior et al. This model was satisfactorily adjusted, mainly for the osmotic dehydration at atmosphere pressure. VA and the calcium increased the ascorbic acid retention in 29.33 and 85.06%, respectively. VA increased water loss up to 53% and ions incorporation, especially that of potassium (648%). The VA caused a higher total color difference, maximum stress and elasticity as compared to the osmotic dehydration at atmospheric pressure.Industrial relevanceThe present paper evaluates the osmotic process with atmospheric and reduced pressures and the production of osmodehydrated eggplant slices with reduced sodium content by the partial replacement of sodium chloride by potassium chloride and calcium chloride. Vacuum can accelerate the osmotic process and enhance the diffusion of water and solutes within the products. The coupling of sodium substitution with reduced pressure could offer an interesting array of different processes and healthier products. This project is a feasibility study of the partial replacement of NaCl by KCl and CaCl2 and the application of vacuum with regard to effects on mass transfer parameters and the chemical, optical and mechanical properties of osmodehydrated eggplant slices.