Development of Microbial Oil Wax-Based Oleogel with Potential Application in Food Formulations

Bio-based wax esters derived from microbial oil have been evaluated as a novel raw material for the production of olive oil-based oleogel. The oleaginous yeast Rhodosporidium toruloides was cultivated in batch fermentation using very high polarity cane sugar as carbon source for the production of a total dry weight of 23.8 g/L with an intracellular microbial oil content of 34% (w/w). The microbial oil was enzymatically converted into oleyl and cetyl wax esters using non-commercial lipases. The highest oil to ester conversion yields for oleyl (94%) and cetyl (91.3%) wax esters were achieved at 40 degrees C and 50 degrees C, respectively. When limonene was used as green solvent in the esterification reaction, the high melting temperature cetyl wax esters were produced at 35 degrees C with a high conversion yield of 87.5%. Subsequently, the microbial oil-derived cetyl wax esters were used for the production of the olive oil-based oleogel. The evaluation of the physical properties (i.e., color, crystal morphology, texture, rheological, and thermal behavior) of the oleogel showed that it was rheologically and thermally suitable for applications in spreadable fat products. This study demonstrated that microbial oil derivatives could be used as novel bio-based raw materials in the preparation of oleogels with potential use in fat-based food products.