Preparation and characterization of foxtail millet bran oil using subcritical propane and supercritical carbon dioxide extraction

Abstract

The foxtail millet (Setaria italica Beauv) bran oil was extracted with traditional solvent extraction (SE), supercritical carbon dioxide extraction (SCE) and subcritical propane extraction (SPE) and analyzed the yield, physicochemical property, fatty acid profile, tocopherol composition, oil oxidative stability in this study. The yields of foxtail millet bran oil by SE, SCE and SPE were 17.14 %, 19.65 %, 21.79 % of raw material weight (corresponded to 75.54 %, 86.60 %, 96.03 % of the total amount of the oil measured by using Soxhlet extraction), respectively. The effect of the extraction methods on the physicochemical properties (peroxide value, saponification value and color) was significant while the difference in fatty acid profile was negligible based on GC analysis. The major components of vitamin E in the obtained oils were identified as α-and β-tocopherols by HPLC, and SPE was superior to SE and SCE in the extraction of tocopherols. In Rancimat test, the oil obtained by SPE showed the highest oil oxidative stability, which could attribute to its high tocopherol content and low peroxide value. In view of oil quality, SPE employed smaller times and lower pressures compared to SE and SCE. SPE was a suitable and selective method for the extraction of the foxtail millet bran oil.

Extraction of macauba kernel oil using supercritical carbon dioxide and compressed propane

“…Macauba kernel oil extracted with subcritical propane showed higher oxidative stability as compared to that obtained using supercritical CO 2 , i.e., 446.24 and 77 min at 403 K, respectively. A similar effect was observed in studies by Shi et al and Teixeira et al…”

“…Thus, high yields are obtained in a shorter extraction time, with a smaller volume of solvent and lower pressures than those reported for carbon dioxide . In addition, it has been reported that vegetable oils extracted with propane demonstrate good thermal stability, with high oxidative induction times when compared with organic solvent extraction techniques and with supercritical CO 2 . However, it is flammable, which necessitates the use of an explosion‐proof extractor using local exhaust ventilation …”

Extraction and characterization of radish seed oils using different methods

“…Tocopherol (α-, β-and γ-isomers) contents of the oils were estimated according to the method of Shi et al [13], using an LC-10Avp High Performance Liquid Chromatography (Shimadzu, Japan), fitted with a RF-10AXL fluorescence detector (Shimadzu, Kyoto, Japan). Each oil was dissolved in n-hexane and eluted on a silica column (250 × 4.6 mm, 5 μm) (Dalian Yilite, Dalian, China) with n-hexane:isopropyl ether (99 : 1,v/v ratio) at 0.8 mL/min.…”

Efficient and eco-friendly extraction of corn germ oil using aqueous ethanol solution assisted by steam explosion

“…To obtain healthy nutritious oil through eco-friendly process, several green extraction methods have been researched at laboratory scale, including aqueous enzymatic method (Dickey et al 2010(Dickey et al , 2008Karlovic et al 1994;Moreau et al 2009) and supercritical fluid extraction (Rebolleda et al 2012;Shi et al 2015). However, the aqueous enzymatic method of extraction has several critical problems which restricted its large-scale industrialization.…”