Experimental investigation of sago drying

Abstract

Drying is a simple method of removal of moisture from the food into the surrounding atmospheric air with the objective of preserving the food by effectively inhibiting the growth of bacteria, mold and yeasts. Drying constitutes an important and inevitable part in the food manufacturing industries. Sago manufactured out of tapioca tuber is consumed widely in India and it is a favourite nutritional food for sick persons and infants. Drying is considered as an essential process in the manufacturing of Sago since it decides the final characteristics and quality. As per Bureau of Indian Standards, Sago should be dried to at least 11% moisture for safe storage. In this study, an investigation of drying of Sago was carried out in a forced convective hot air cabinet tray drier to ascertain the influence of temperatures of air at 60°C, 70°C, 80°C, and bed thicknesses 7.0 mm, 10.5 mm and 14.0 mm for a consistent air flow of 2.0 m/s for generation of the experimental data. Sago after roasting (partial gelatinization) was collected from the Sago industry and used for conducting experiments. The drier was made to run at no load conditions for around 1 hour to ensure steady state conditions. Initial moisture content of Sago on wet basis was determined by the oven dry method of heating the Sago at 100°C in an oven for more than 4 hours and by determining the weight of dried mass until no change of weight observed in the repeated readings. Nine experimental runs were completed with the permutation and combination of air temperatures of 60°C, 70°C, 80°C and thicknesses of 7.0 mm, 10.5 mm and 14.0 mm and the experiments were run in triplicate and average values taken in order to rule out random error and experiment biasReading was taken once every 15 minutes to determine the loss of moisture and until there was no appreciable moisture loss the above procedure was continued. In order to ensure fitting of data to the twelve widely used thin layer drying models effectively, the moisture content data taken at different temperatures an