Osmotic Dehydration of Garden Egg (Solanum aethiopicum): the Shrinkage and Mass Transfer Phenomena

Osmotic dehydration is usually employed to lower the water activity of fruits and vegetables and thus has a wide range of application in the food preservation. This study investigates the osmotic dehydration of garden egg (Solanum aethiopicum) using sodium chloride solution (NaCl) of varying concentration (20, 40 and 60 %w/w) as osmotic solutions. Different parameters such as percentage water loss (%WL), weight reduction (%WR) and solid gain (%SG) were investigated at different solution temperature (25, 35, 45, 55, and 65°C), agitation time (20, 40, 60, 80, 100, 120, 140, 160 and 180 min) and osmotic solution concentration (20, 40 and 60 %w/w) to ascertain the optimum dehydration performance of the process. The performance efficiency of the process was evaluated at different osmotic solution concentration (20, 40 and 60 %w/w) with respect to time (20-180 min) at constant temperature (40 OC). The performance efficiency of the process was also evaluated at different osmotic solution concentration (20, 40 and 60 %w/w) with respect to temperature (25, 35, 45, 55, and 65°C) at constant time (180 min). The results of this study showed that %SG and %WL increased with increase in concentration with respect to time whereby the optimum values for these parameters being 157% and 45.80% respectively were achieved at 60 %w/w osmotic solution concentration, while optimum %WR (34.70%) with respect to time was achieved at J Anal Tech Res 2020; 3 (1): 1-17 DOI: 10.26502/jatri.009 Journal of Analytical Techniques and Research 2 40 %ww osmotic solution concentration. Therefore, the order of %SG and %WL by the garden egg with respect to time was 60 > 40 > 20 %w/w. The optimum %SG, %WL and %WR were achieved at 65 oC in 60 %w/w osmotic solution with the values of 133, 53.11 and 40.10% respectively. The results from this study therefore showed that osmotic dehydration could potentially reduce water activity of garden egg.