Effect of Drying Methods on the Quality Characteristics of Fenugreek (Trigonella foenum-graecum) Greens

Different drying methods were investigated for efficient
dehydration of fenugreek (Trigonella foenum-graecum) greens for
optimal retention of color and its constituents. Accordingly, hot
air (HA, 40�C, 58–63% RH), low humidity air (LHA, 40�C and
28–30% RH), and radiofrequency (RF, 40�C, 56–60% RH) were
explored for efficient drying of fenugreek greens. The three singlelayer
drying models (Exponential, Page, and Modified Page) tested
showed excellent fit (R2¼0.92–0.99) for all three drying methods.
The time required for drying with LHA and RF was less (�27%),
as compared to HA drying. LHA-dried fenugreek had superior
green color and a more porous and uniform structure than those
obtained from RF and HA drying. Aqueous methanolic (60:40)
extract of fenugreek greens dehydrated by LHA exhibited the
highest radical scavenging activity. Dehydrated fenugreek greens
showed good consumer acceptance as well as shelf life.