Effect of Osmotic Pretreatment on Hot Air Drying Kinetics and Quality of Chilean Papaya (Carica pubescens)

Abstract

The effect of osmotic pretreatment on the mass transfer kinetics and quality of dried rehydrated Chilean papaya was researched. Osmotic treatments were sucrose solutions of 40, 50, and 60% w/w and dried at 60°C; non-pretreated samples were dried at different temperatures (40, 60, and 80°C). Quality parameters were analyzed: proximal composition, rehydration ratio, water-holding capacity, color, vitamin C content, firmness, and microstructure. Non-pretreated samples showed a clear turgor loss, color loss. and low ascorbic acid retention when rehydrated. Osmotic pretreatment improved the quality of rehydrated papayas, showing higher ascorbic acid retention and best firmness and color. Microstructure is better preserved in the pretreated papayas than in the non-pretreated samples, although this difference is minimal.

Keywords:

• Drying kinetics
• Microstructure
• Osmotic dehydration
• Papaya
• Rehydration

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the Research Department of Universidad de La Serena (DIULS), La Serena, Chile, for providing financial support for the publication of this research. In addition, we thank the Microscopy Service of Universidad Politécnica de Valencia, Spain, for assistance in relation to the Cryo-SEM micrographs.

Notes

^a Osmotically pretreated samples were submerged for 120 min at 40°C in a sucrose solution at different concentrations.

Data are expressed as average ± standard deviation in three replicates. Values in the same column having the same capital letter for each parameter are not significantly different at a confidence level of 95%.