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Accueil du site → Doctorat → Allemagne → 2015 → Improved oil processing and protein extraction for better valorization of Jatropha curcas L. nuts

Technische Universität Berlin (2015)

Improved oil processing and protein extraction for better valorization of Jatropha curcas L. nuts

Gofferjé, Gabriele

Titre : Improved oil processing and protein extraction for better valorization of Jatropha curcas L. nuts

Erhöhung der Wertschöpfung von Jatropha curcas L. Nüssen durch die Entwicklung verbesserter Verfahren zur Ölraffination und Proteinextraktion

Auteur : Gofferjé, Gabriele

Université de soutenance : Technische Universität Berlin

Grade : Doktor der Naturwissenschaften -Dr. rer. nat.- 2015

Résumé
The awareness of environmental problems caused by an increasing standard of living lead to a revised view on industrial processes and the handling of resources. During the last decades, the tropical, non-edible plant Jatropha curcas L. became a focus of interest especially with respect to its high oil content. In order to increase the sustainability of its utilization the present work deals with the establishment of alternative enzymatic processes for the oil refining as well as with the extraction and application of the protein, the most valuable by-product inherent to the residues left after oil extraction from the Jatropha seeds. Enzymatic degumming of crude Jatropha oil was performed successfully applying Lecitase® Ultra. Phosphor content can be decreased below 4 ppm. Enzymatic neutralization was achieved esterifying the free fatty acids with glycerol by an immobilized lipase from Rhizomucor miehei. Initially, the crucial influencing parameters were determined and afterwards the reaction was optimized by the help of a statistical design of experiments. The process allows acid number reduction to 0.3 mg KOH per g of oil. Residual fatty acids are easily removed within the following refining steps. According to a kinetic investigation, the enzymatic neutralization is expected to follow a Ping Pong mechanism with dead end inhibition by the acyl-acceptor glycerol. Enzyme regeneration was also investigated and found to be most effective applying isopropanol and n-hexane allowing a reutilization of the enzyme in at least 13 cycles. In order to extract the protein from aqueous-extracted as well as from screw-pressed Jatropha residue an aqueous and an enzyme-assisted process were developed. Protein yields of about 75% were obtained. Different methods for protein recovery and purification subsequent to protein extraction were performed and evaluated. In principle, Jatropha proteins show good emulsifying as well as gelation behaviour. No foam forming capacity is measured. The functionality of enzymatically extracted protein is minor to the functionality of aqueous-extracted protein. Jatropha protein owns potential for its utilization in technical applications such as emulsifiers, biodegradable bags or antifoam reagent. The current work revealed Jatropha curcas as a promising source of oil and protein to be valorized for their use in technical applications.

Mots clés  : Enzymatische Raffination Nachhaltigkeit Proteinextraktion Enzymatic refining Protein extraction Sustainability

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