Jatropha press cake, by-product after oil expression from Jatropha seeds, contains 24–28% protein on dry basis. Objectives of this research were to investigate functional properties, such as solubility, emulsifying, foaming, film forming, and adhesive properties, of Jatropha press cake proteins and compared those with relevant industrial proteins. From our study, we found that protein extracted from press cake proteins had a solubility of about 90% above pH 9. Emulsifying properties of press cake protein were comparable to sodium caseinates and reached the highest value at pH 9–10. Jatropha proteins formed films with tensile strength of 0.4–1.8 MPa with 10–75% elongation, which were below soy protein or wheat-gluten. Further oil removal from press cake decreased emulsifying properties, while increased foaming and adhesive properties of the extracted proteins. Protein extracted from de-oiled press cake showed better foaming properties than sodium caseinate at pH 10, but lower than egg white protein at all pH. Furthermore, press cake protein showed better adhesive properties than casein adhesives at the same dry matter content. Based on these results, Jatropha press cake protein showed most promising results on adhesive and emulsifying properties, which indicate the potential of Jatropha press cake protein as emulsifier or paper adhesive.
- soy protein
- antinutritional factors