Abstract: The subcritical butane extraction of wheat bran oil was optimized using response surface methodology with a Box-Behnken design. The optimum extraction conditions were determined as follows: extraction temperature 40 ℃, solvent-to-solid ratio 1:3 (g/mL), extraction time 30 min, and 3 extraction cycles. The chemical composition of the oil extracted under these conditions was detected by gas chromatography-mass spectrometry (GC-MS); qualitative analysis was performed by comparing the mass spectra of analytes with the standard spectra in a mass spectral database and quantitative analysis by area normalization method. A total of 23 components were identified, including 17 fatty acid esters (78.17%) and 5 sterol compounds (19.35%). The main fatty acid methyl esters were methyl ester (11.22%), methyl linoleate (41.77%), methyl oleate (13.36%), methyl stearate (2.87%) and methyl 9-eicosanoate (1.99%). The major sterol compounds were β-sitosterol (8.13%), stigmastanol (4.73%), ergostanol (3.42%) and campesterol (2.30%).

Key words: wheat bran, subcritical, response surface methodology optimization, gas chromatography-mass spectrometry (GC-MS), fatty acid composition