Effect of drying temperature on physical properties of fermented dried locust bean flour

Drying plays a major role in food processing as it reduces the activities of micro-organisms and hence preserve food from deterioration. It has been reported that drying imposes new changes to the physical properties of the product which may in turn affect its handling, packaging and usability. The present research work, therefore aimed to evaluate the effect different drying temperature on physical properties of fermented dried locust bean flour. The local fermented locust bean was dried at different temperature of 50, 60, 70, 80 and 90°C at airflow rate of 1.8 kg/min. then milled and Investigated on final moisture content, bulk density, water retention ratio, flour wetting time, and swelling capacity of the fermented dried locust bean flour. The effect of drying temperature was found to be significant (p ≤ 0.05) on all the physical properties investigated except bulky density (0.638 g/ml). As the drying temperature increased from 50 to 90°C, final moisture content decreased significantly from 5.62 to 3.52%. Whereas, water retention ratio, wetting time, swelling capacity, porosity ratio and water retention ratio increase from 1.96 to 2.5 m/g, 153 to 299 s, 2.26 to 2.44, 0.81 to 0.91 and 1.96 to 2.5 m/g respectively. These findings could prove useful in the modeling of locust bean drying and to flour millers and pelletizer who may want to use locust bean flour as a sole or composite flour for different production and application. Keywords: Fermented locust bean flour, physical properties, modeling, pelletizer, miller, drying temperature, final moisture content.