Drying and quality characteristics of different components of alfalfa

This study investigated the effect of air temperature (100～200℃) and velocity(0.15～0.45 m/s) on drying characteristics and quality of different alfalfa components. The chopped alfalfa components, including stems, crushed stems, crushed stems with attached leaves, and leaves were used for the study. The moisture losses under different drying conditions and periods were measured. The qualities of dried products, including color, protein and fiber content were also examined. The leaves and uncrushed stems had the highest and lowest drying rates among the four components. The increases of drying temperature and air velocity resulted in higher drying rates of all components. But the temperature increase also caused high difference in the moisture of leaves and stems of dried stems with attached leaves. No significant difference was found for the crude protein in leaves below 160℃. Alfalfa greenness of leaves increase with the increase of air velocity and temperature in low range below 0.3 m/s and 160℃, respectively. Based on the test results, to achieve high drying rate and desirable product quality of alfalfa, a combination of 160℃ and 0.3 m/s of air velocity were suggested.