Abstract: The microwave-assisted extraction of volatile oil from the residue left over after lutein extraction Tagetes erecta L. was optimized by one-factor-at-a-time and orthogonal array design methods. Oil yield was investigated with respect to solvent-to-material ratio, extraction time and microwave power (low, medium and high fire). The optimal extraction conditions were petroleum ether as the extraction solvent at a solvent-to-material ratio of 6:1 for 60 s extraction under the assistance of high-fire microwave power. Under the optimal extraction conditions, an oil yield of 1.575% was achieved. The chemical composition of the volatile oil was analyzed by gas chromatography-mass spectrometry (GC-MC) and 19 compounds were identified.

Key words: Tagetes erecta L., volatile oil, microwave extraction, gas chromatography-mass spectrometry