3.7-2. Drying Tests with a Foodstuff. In order to test the feasibility of drying a certain foodstuff, drying data were obtained in a tray dryer with air flow over the top exposed surface having an area of 0.186 m2. The bone-dry sample weight was 3.765 kg dry solid. At equilibrium after a long period, the wet sample weight was 3.955 kg H2O + solid. Hence, 3.955 3.765, or 0.190, kg of equilibrium moisture was present. The following sample weights versus time were obtained in the drying test: Time (h) Weight (kg) Time (h) Weight (kg) Time (h) Weight (kg) 0 4.944 2.2 4.554 7.0 4.019 0.4 4.885 4.404 9.0 3.978 0.8 4.808 4.2 4.241 12.0 3.955 1.4 4.699 5.0 4.150 a. Calculate the free moisture content X kg H2O/kg dry solid for each data point and plot X versus time. (Hint: For 0 h, 4.944 - 0.190 3.765 = 0.989 kg free moisture in 3.765 kg dry solid. Hence, X = 0.989/3.765.) 3.0