Dissemination activity type: 
Article type: 
Journal article
Title of article: 
Impact of critical control-point based intermittent drying on drying kinetics and quality of carrot (Daucus carota var. laguna)
Full Name: 
Rosalizan Md. Saleh
Country of publication: 
Web link: 
Target group(s): 
General public
Name of Journal: 
Thermal Science and Engineering Progress
Volume number: 

The objective of this research was to investigate the effect of intermittent drying on drying kinetics, moisture diffusivity and quality of organic carrot. The intermittent drying was conducted at 60 °C and 70 °C with a constant air velocity of 0.6 m/s. The drying process was paused at 30% moisture levels at which the inflection point for degradation of total carotenoids lies in this region and also at 40% moisture level in order to investigate the possibility of increasing the retention by changing the settings at slightly higher moisture content. Tempering was performed for 1 and 3 h under ambient condition and the results showed a significant effect on drying time and effective moisture diffusivity. Specific energy consumption reduced by 17.0% to 25.5% after tempering at 1 and 3 h for both moisture levels. Drying at 60 °C and tempering at a moisture level of 30% shortened the effective drying time by 24.5% compared to that of 18.2% when tempering at 40% moisture level. Moisture diffusivity for both moisture levels and tempering periods increased when drying was conducted at 70 °C as compared with 60 °C. The ideal drying condition was found to be at 60 °C with the tempering time of 3 h at 30% moisture level (wb) resulted in the best retention of total carotenoids (76.9% ± 2.42), total color change (8.1 ± 1.67) and rehydration ratio (0.4 ± 0.01).