Drying Rate

Experiment 4 Effect of Temperature on the Drying Rate Date Performed: 15 January 2013 Date Submitted: 31 January 2013

I.

Introduction The origin of food technology perhaps is cooking, and cooking more food to make it in a more palatable form and, and extend shelf life considerably. In extending the shelf life of foods, food preservation is used. There are different ways in preserving food and one of these is drying/ dehydration. Drying is the removal of moisture in a food. In this aspect, the reduction of moisture content reduces water activity, and makes water not available for microorganisms to grow and pathogens to survive (Rao, 2010).

According to Barbosa-Canovas (1996), understanding the real mechanism of the drying process for the equipment design and best quality food products is necessary. With this necessity, this experiment aims to determine the effect of drying temperature on drying rate of the sample.

II.

Methodology The sample used in the experiment was the same in experiment 3 which was the purple sweet potato. It was first washed and peeled cut into thin slabs which was measured as 1in x 1in x1mm. The samples were then weighed together with the wire baskets used in the last experiment. The other part of the samples was chopped and moisture was analyzed using the IR moisture analyzer. The samples were then subject to drying. The first 5 samples were dried with 10-min intervals and the remaining samples with 20-min intervals. Samples were allowed to cool and then weigh to get its dried weight.

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Table 1.0 The drying data of the 1-mm thick sweet potato from the experiment.

T, min ∆t, min Moi, g Mfi Mds, g Xw, water/ wet sample 0 10 20 30 40 50 70 90 110 140 170 --10 10 10 10 20 20 20 20 30 30 0.7005 0.7005 0.7243 0.7908 0.7722 0.7476 0.6660 0.8436 0.7730 0.7652 0.6673 0.5923 0.5923 0.5493 0.5852 0.4790 0.4294 0.2886 0.3060 0.2654 0.2592 0.2568 0.2799 0.2799 0.2895 0.3161 0.3086 0.2988 0.2662 0.3372 0.3089 0.3059 0.2667 0.6003...