Improving Jatropha curcas seed protein recovery by using counter current multistage extraction

Jatropha curcas seed press cake contains 23 wt% proteins (dry basis). Due to the toxic compounds in Jatropha, we will use the proteins for non-food applications. Related to non-food applications, an efficient protein extraction to obtain a high protein recovery and high protein concentration with good protein functional properties is required. To achieve this, we conducted protein extractions at room temperature by using different solvents at various solvent to solid ratios and performed multistage counter current extraction to improve protein recovery and protein concentration. We obtained the highest protein recovery of 82% by using 0.055 M NaOH at solvent to solid ratio of 10 g/g after four-stage counter current extraction. By using 0.055 M NaOH extraction at lower solvent to solid ratio of 4 g/g, protein recovery was 35% after one-stage extraction and improved up to 71% with a high protein concentration of 63 mg/mL after four-stage counter current extraction. The highest amount of protein was precipitated from crude extracts at pH 4–5.5 and resulted on precipitate with protein content of 70%. The multistage counter current extraction did not influence Jatropha seed protein molecular weight distributions, which were within the range of 3–98 kD