Experimental Study of Drying Parameters of Ginger at Different Temperature and Moisture Content

Abstract

Drying provides extended shelf life to agricultural crops in general and thus proper design of dryer will assist in drying them to acceptable level and quality. To design adequate dryer, necessary drying parameters of drying materials is necessary. This work involves experimental determination of effective drying parameters such as moisture content, moisture diffusion coefficient, density (true and bulk), specific heat, thermal conductivity and thermal diffusivity of ginger and to analyze these parameters in relation to each other. Fresh ginger rhizomes were washed to remove soil from the field, peeled and washed again in clean water and sliced into thin pieces. The sliced ginger was heat-treated by adding 200ml of clean water and steaming for 5–8 minutes in an aluminum pot, to a temperature of 85–90 oC, and a light brown colour. Microwave oven, calorimeter, desiccators, thermometers, triple beams balance, micrometer screw gauge were used to determine the drying parameters of ginger. Effect of temperature and moisture content on some thermal properties was determined. The results of the experiments shows that average initial moisture content for the ginger samples was 72.31%, the true and bulk densities of the sample increased linearly from 0.5809 to 0.6338g/cm3 and 0.7405 to 0.7972 g/cm3 respectively between the temperatures of 45 – 75 °C. The specific heat capacity of ginger varied from a minimum of 1.568kJkg-1K-1 to a maximum of 2.026kJ kg-1K-1, with temperature in the range of 45oC to 75oC and moisture content in the range of 24.43 to 46.19 % (d.b). The thermal conductivity of ginger samples varied from 0.316×10-3 to 9.763×10-4 Jm-1S-1 oC; as the moisture content and temperature increased. Thermal diffusivity of the ginger increased linearly from 3.149×10-8 to 4.438×10-8 m2s-1 for ginger with increase in moisture content and temperature. Conclusively, the experimental study analysis show that specific heat of ginger varies with temperature. Also, there is variation in length, breath and thickness of ginger when subjected to temperature. Therefore, it can be said that ginger do shrinks when it is subjected to heat.