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 degrees C, 58-63% RH), low humidity air (LHA, 40 degrees C and 28-30% RH), and radiofrequency (RF, 40 degrees C, 56-60% RH) were explored for efficient drying of fenugreek greens. The three single-layer drying models (Exponential, Page, and Modified Page) tested showed excellent fit (R-2 = 0.92-0.99) for all three drying methods. The time required for drying with LHA and RF was less (similar to 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.