Influences of Osmotic Dehydration on Drying Behavior and Product Quality of Coconut (Cocos nucifera)

Abstract

This research was conducted to assess the drying kinetics and product quality during osmotic dehydration and air drying of coconut cuts. The coconuts were osmotically pretreated by different concentration of sugar solution (40 °Brix, 50 °Brix, and 60 °Brix) and temperature of osmotic solution (35°C, 45°C and 55°C) were maintained. The proportion of fruit to solution was maintained 1:4 (w/v) and pretreatment process length was 3 hours. Higher osmotic solution temperature at 55°C with low concentration 40 °Brix resulted in a huge reduction of antioxidant activity, vitamin C, polyphenol, and color contents while higher osmotic solution concentration at 50 °Brix with lower temperature 35°C held more. The present investigation likewise exhibited that moisture loss and solute gain rate extended with the increasing of osmotic solution temperature and concentration. The outcomes demonstrated that drying regime was typically in the falling rate period. We used regression analysis to the experimental drying data to fit three thin layer drying models. The most appropriate model(s) was selected using correlation coefficient (R2) and root mean square error (RMSE). The page model showed a better fit of the experimental drying data (as compared to other models) on the basis that R2> 0.9997 and RMSE < 0.0011. These data represent a good contribution to further investigation on the mass transfer kinetics and also demonstrated that fruits could be preserved with higher nutrient applying osmotic dehydration technique.