Abstract:

In this study, millet bran oil was extracted from millet bran with n-hexane, and its physico-chemical properties and
fatty acid composition were analyzed. The extraction process was optimized by Box-Behnken design using response surface
methodology (RSM) on the basis of single factor experiments. Results indicated that the optimal extraction process was
found to be extraction at 55 ℃ for 6 h with a material/liquidratio of 1:7 (g/mL). Experiments conducted under the optimized
conditions resulted in an extraction yield of 83.3%, which was consistent with the theoretical value. The freezing point of
millet bran oil was 19.0 ℃, the acid value was 5.7 mg KOH/g, the peroxide value was 2.1 mmol/kg, the saponification value
was 185.1 mg KOH/g and the iodine value was 118.9 g I2/100 g. In addition, 10 fatty acids were identified in the millet bran
oil, and the total content of unsaturated fatty acids was 82.5%, including 63.6% linolic acid, 14.8% oleic acid and 2.7%
α-linolenic acid.

Key words: millet bran oil, extraction, response surface methodology, physico-chemical properties, gas chromatographymass spectrometry, fatty acids