Effect of cabinet drying on nutritional quality and drying kinetics of fenugreek leaves (Trigonella foenum-graecum L.)

In the present investigation, fresh fenugreek leaves were blanched in water (80 °C), steam and water added with three chemicals namely potassium metabisulphite (0.5%), magnesium oxide (0.1%) and sodium bicarbonate (0.1%) followed by drying at 40 °C and 50 °C respectively, at 1.1 m/s air velocity in a cabinet dryer. The samples were analyzed for various parameters such as moisture content, moisture ratio, rehydration ratio, ascorbic acid, total chlorophyll and β-carotene content. Among three treated samples, the water added with chemicals blanched samples showed the best result in terms of various quality parameters and maximum nutrient retention after drying at 40 °C. Five mathematical models for thin layer drying were used to predict the drying behavior of the fenugreek leaves. Considering suitable statistical parameters studied for each model, Midilli model showed the best performance and thus applied for this study to predict the drying behavior of fenugreek leaves in above stated conditions.