Castor bean cake as raw material for biodegradable material

The valorization of castor bean cake could contribute to the success of the production of biodiesel from castor bean. Thus, the objective of this work was to study the potential of castor bean cake as a protein source of interest for the production of biodegradable material. For the characterization of the raw material, the castor bean was submitted to classical chemical analyses. And, the protein extractions tests were conducted at different conditions of pH, temperature, concentration of the cake in the extraction solution and agitation speed. The protein extracts (supernatant) were separated from the solid residues (decanting) by centrifugation (4000rpm for 20 minutes) and analyzed for protein, dry matter and ash. The castor bean cake had high protein content (40%) and crude fiber (29%) compared to other components (ash, lignin, cellulose, hemicelluloses and lipids). The cake might be considered rich in calcium (1.5%), potassium (0.8%), phosphorous (0.6%) and magnesium (0.5%) compared to other minerals (Na, S, B, Zn, Mn, Cu and Fe). The processes of protein extraction showed yields between 16 and 38%, based on the initial content of protein in the cake. In general, the increase in pH contributed to the increase in the yield of protein extraction from the castor bean cake. Furthermore, higher yields were obtained in the extraction with low concentration of cake in the extraction solution. An analysis electrophoresis of the extracted protein showed the presence of albumin and globulin, proteins widely used in biodegradable materials technology. It can be concluded that castor bean cake is a good source of protein for the industry of biodegradable materials, and that the extraction of these proteins continues to generate considerable residue with high protein content, which may be considered for use as fertilizer or, if detoxified, as a component of animal feeds.