ISBN 978-3-8439-3510-4

978-3-8439-3510-4, Reihe Biotechnologie

Daniela von der Haar
Development of an Enzymatic De-acidification Step for the Improvement of Rapeseed Oil Refining and Simultaneous Enhancement of Diacylglycerol in the Edible Oil

134 Seiten, Dissertation Technische Universität Dortmund (2017), Softcover, A5

Zusammenfassung / Abstract

The increasing awareness of food industry and consumers on food production processes leads to a revised view on consisting industrial processes. Special interest is put on the handling of energy, human resources and raw materials. In this context, the application of biocatalysts in food industry became a focus of interest, in particular as there exist some processes which are already used since thousands of years, like yeast and lactic acid fermentation.

In order to increase the sustainability of vegetable oil refining the present work deals with the establishment of an alternative enzymatic process for the de-acidification of rapeseed oil. Additionally, the simultaneous enrichment of nutritionally valuable diacylglycerols should be evaluated.

Enzymatic de-acidification of rapeseed oil was achieved esterifying the free fatty acids with monoacylglycerol by an immobilized lipase. Initially, a lipase from Rhizomucor miehei was identified as suitable biocatalyst. After determination of crucial reaction parameters their optimization occurred by statistical design of experiments. The process allows the reduction of the fatty acid content down to 0.3 % (w/w).

According to a kinetic investigation, the enzymatic neutralization is expected to follow a Ping Pong mechanism with slight competitive inhibition by the acyl group acceptors. However, a continuous addition of the acyl group acceptor to the reaction system reduces this inhibition. Simultaneously to the reduction of free fatty acids, the developed process leads to an enrichment of nutritionally valuable diacylglycerols up to 23.8 % (w/w). To enhance the economic efficiency of the process, enzyme regeneration was investigated and found to be most effective applying isopropanol and n-hexane treatments which allow a reuse of the enzyme in 14 consecutive cycles.

Summarizing, the current work revealed the potential of an enzymatic de-acidification of vegetable oils as promising alternative for existing industrial, chemical processes also enabling the enrichment of diacylglycerols in edible oils.