The deterpenation of orange peel oil in most industries is accomplished by vacuum distillation, but surprisingly little information on this matter can be found in the open literature. This work reports recent results on orange peel oil deterpenation carried out in an automatic vacuum distillation column operated in the semibatch mode at the temperatures of 50, 65, and 80 degreesC, at 10, 20, and 30 mbar, and with reflux ratios of 0.25, 0.50, and 0.75. The concentrates were analyzed with regard to the oxygenate compound content by gas chromatography coupled with a mass spectrometer (GC-MS) and evaluated by sensory analysis, and also with regard to the aldehyde content. As one could expect, there is a strong relationship between oil quality, as revealed by the sensory analysis, and chemical composition, as determined by GC-MS. The concentration factor and process yield, as expressed by "fold," together with the analysis results show that it is possible to obtain high quality concentrates simply by manipulating the operating variables in the vacuum fractionation process.