The objective of this work was to evaluate the effect of moisture content on castor bean fruit shrinkage, dimensional characteristics and shape during drying. Castor bean fruits were harvested with 2.50 (d.b.) moisture content and dried at 40ºC up to final moisture content of 0.11 (d.b.). The size of the fruits was determined according to the shrinkage rate and the shape analyzed through the sphericity and circularity method. Castor fruit shrinkage was determined by the ratio between its volume with respective moisture content and its initial volume. Based on the obtained results, it can be concluded that the shape castor bean fruits is influenced by reduction in moisture content promoting the sphericity and circularity values as the moisture content is reduced. The dimensional characteristics (length, width and thickness) and the mean geometric diameter values of the fruits are reduced as the moisture content is reduced. The moisture content reduction influenced unit volumetric shrinkage and fruit mass, resulting in reduction of 46.0 and 63.0%, respectively. The polynomial model, among all tested, best fit the shrinkage phenomenon of castor bean fruits.
Ricinus communis L.; physical properties; shrinkage
