A simple process to obtain onion oil by direct solvent extraction
was proposed. Several solvents commonly utilized in the food
industry were tested for their selectivity in the extraction of the
oil of onion. Diethyl ether and methylene chloride appeared to be
the most suitable solvents for the extraction operation. The direct
solvent extraction method produced a yield of onion oil approximately
seven times higher than the yield obtained by the steaim distillation
method.
A process of fermentation of the ground raw onions was used
prior to the solvent extraction operation. This produced an improvement
in the onion oil yield of 60% over the normal solvent extraction
method.
In order to determine the quality of the onion oil obtained, refractive
index, specific gravity, melting point, and sulfur content
were determined. Sulfur content in the onion oil obtained by the
method proposed here had one-third (weight basis) of the sulfur content
of commercial onion oil.
Two organoleptic evaluations were conducted for commercial onion
oil and for the onion oil obtained by direct solvent extraction: odor
threshold determination and comparative flavor evaluation. The commercial
onion oil showed a lower threshold concentration (1.6 ppb)
than the onion oil obtained in the laboratory (8.4 ppb). With respect
to the comparative flavor tests, the test panels did not detect a
statistically significant difference between the flavor of commercial
onion oil and the oil obtained by the method proposed here. / Graduation date: 1982
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26005 |
| Date | 21 October 1981 |
| Creators | Hernandez-Molinar, Ernesto |
| Contributors | Beavers, Darrell V. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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