Infrared assisted dry-blanching and hybrid drying of carrot.

Infrared (IR) blanching and IR assisted hot air (hybrid) drying of carrot slices were attempted and their performance
(processing time, retention of vitamin C and rehydration characteristics) was compared with conventional blanching
and drying techniques. Intermittent heating of carrot slices using IR radiation (chamber maintained at 180–240 ◦C)
for 8–15 min resulted in desired level of enzyme inactivation. The time required for blanching of carrot slices (10 mm
thick) using hot water, steam and IR radiation was 5, 3 and 15 min, respectively. Retention of water soluble vitamin
C was higher (62%) in IR blanched carrot as compared to water (43%) and steam (49%) blanching. IR blanching
reduced the moisture content by 13–23% (absolute). IR blanched samples dried by hybrid mode took ∼45% lesser
time compared to water blanched–hot air dried samples. Higher rehydration moisture of dried samples indicated
the retention of cell structure during IR blanching. Vitamin C retention was ∼39% higher in IR blanched–hybrid dried
slices compared to water blanched–hot air dried. The study shows the potential application of dry-blanching and IR
assisted hybrid drying in food processing for improving product quality.