Effect of Pretreatments on Drying and Rehydration Kinetics and Color of Sweet Potato Slices

Abstract

The effect of air temperature and pretreatments (KMS: citric acid) on drying kinetics of sweet potato slices was investigated. Drying experiments were performed in a tray dryer. In falling rate period, moisture transfer from sweet potato slices was described by applying the unsteady-state Fickian diffusion model, and the rate constant (k) were calculated. The effect of temperature on k could be interpreted according to Arrhenius law. Drying rate and therefore k values were found to be affected by pretreatments. Rehydration rates of dried sweet potato slices at 25, 40, 80°C were also determined and found to be independent of drying conditions and rehydration temperature. The ΔE value was found to be the highest for slices treated at 50°C with 0.5:1.0% KMS and citric acid.

Keywords:

• Color
• Drying kinetics
• Page's model
• Rehydration rate
• Sweet potato

Notes

^a Average of two values.

^a Average of two values.

^a Average of two values.

^a Average of two values.