Modification of aqueous enzymatic oil extraction to increase the yield of corn oil from dry fractionated corn germ

In previous aqueous enzymatic oil extraction (AEOE) experiments we reported a best free oil yield of 49% of the hexane extracted yield of dry fractionated corn germ. In the current experiments, a dispersion of 10% cooked, dry-fractionated germ in water was treated with α-amylase, glucoamylase and a cellulase complex. Free oil was collected by centrifuging a foam fraction of the dispersion. Several dispersion treatments were tried to evaluate their release of free oil and effect on the production of foam. The foam contained up to 8% free oil (dispersed from germ containing 26% oil) and fines oil (not centrifugally separable), protein and germ particles. Treatment with α-amylase and glucoamylase prior to treatment with the commercial cellulase used in previous AEOE studies increased the free oil yields about 25-61% of the hexane-extractable yield. A preliminary cost analysis indicates that oil separation with the amylase enhanced AEOE appears to be preferable to AEOE alone and profitable if crude corn oil cost exceeds $1.1/kg ($0.50/lb).     

Composition and oxidative stability of crude oil extracts of corn germ and distillers grains

The fatty acid composition, Acid Value, and the content and composition of tocopherols, tocotrienols, carotenoids, phytosterols, and steryl ferulates were determined in corn germ oil and four post-fermentation corn oils from the ethanol dry grind process. The oxidative stability index at 110 °C was determined for the five oils, and four oils were compared for their stability during storage at 40 °C as determined by peroxide value and hexanal content. The fatty acid composition of all five oils was typical for corn oil. The Acid Value (and percentage of free fatty acids) was highest (28.3 mg KOH/g oil) in corn oil extracted centrifugally from a conventional dry grind ethanol processing facility and for oil extracted, using hexane, from distillers dried grains with solubles (DDGS) from a raw starch ethanol processing facility (20.8 mg KOH/g oil). Acid Value was lowest in two oils extracted centrifugally from thin stillage in a raw starch ethanol facility (5.7 and 6.9 mg KOH/g oil). Tocopherols were highest in corn germ oil (∼1400 μg/g), but tocotrienols, phytosterols, steryl ferulates, and carotenoids were higher in all of the post-fermentation corn oils. Hexane extracted oil from DDGS was the most oxidatively stable as evaluated by OSI and storage test at 40 °C, followed by centrifugally extracted thin stillage oil from the raw starch ethanol process, and centrifugally extracted thin stillage oil from the conventional dry grind ethanol process. Corn germ oil was the least oxidatively stable. When stored at room temperature, the peroxide value of centrifugally extracted thin stillage oil from the raw starch ethanol process did not significantly increase until after six weeks of storage, and was less than 2.0 mequiv. peroxide/kg oil after three months of storage. These results indicate that post-fermentation corn oils have higher content of valuable functional lipids than corn germ oil. Some of these functional lipids have antioxidant activity which increases the oxidative stability of the post-fermentation oils.     

Protein extraction from defatted wheat germ by reverse micelles: Optimization of the forward extraction

In this work, the forward extraction of defatted wheat germ protein (DWGP) by reverse micelles was studied. The reverse micellar systems were formed by sulphosuccinic acid bis (2-ethylhexyl) ester sodium salt (AOT), isooctane and KCl solution. The effects of AOT concentration, pH, KCl concentration, extraction time, the amounts of defatted wheat germ flour (DWGF), W₀ (the molar ratio of water to surfactant, i.e. W₀ = [H₂O]/[AOT]) and temperature on the forward extraction efficiency of DWGP were tested. On the basis of single-factor experiments, the optimum extraction was achieved by response surface methodology (RSM). The experimental results lead to the conclusion that the highest forward extraction efficiency of DWGP was reached at the AOT concentration 0.06 g/mL, pH 8, KCl concentration 0.1 mol/L, time 30 min, the amounts of DWGF 0.500 g, W₀ 25 and temperature 36 °C. Under these conditions, the forward extraction efficiency of DWGP achieved 37%.     

Oil extraction from coriander fruits by extrusion and comparison with solvent extraction processes

The aim of this work was to optimise a single-screw extruder dedicated to coriander production and to investigate the effects of screw configuration, nozzle diameter and nozzle/screw distance. On the other hand, the coriander fruit was extracted using soxhlet methods, the results were compared with mechanical screw press methods.Maximum yield was obtained with single screw extruder for a configuration allowing the strongest oil expression (nozzle/screw distance: 3 mm, nozzle diameter: 9 mm).Comparing with mechanical press, the maximum yield was obtained by the soxhlet extraction with 21.25%.The effect of the operating parameters on oil quality was not important. In all the experiments tested, the oil quality was very good. The acid value was below 1.8 mg of KOH/g of oil and iodine values were tolerable (44 mg of iodine/100 g of oil).Nine fatty acids were identified, with petroselinic acid accounting for 74-77% of the total fatty acids, followed by linoleic, oleic and palmitic acids, accounting for 12-13%, 4-6% and 3%, respectively, of the total fatty acids.β-Sitosterol was the major sterol in all oils with 28% of total sterols of all oils. The next major sterols in all oils were stigmasterol (24-27% of total sterols) and Δ⁷-stigmasterol (14-18% of total sterols).     

超临界CO_2提取人参籽油工艺研究及人参籽油脂肪酸组成分析

该研究以人参籽为原料,采用超临界CO2流体技术萃取人参籽油,通过正交试验优化了萃取人参籽油工艺参数,再将其与通过冷榨法及溶剂法提取的人参籽油进行对比,测定和比较了不同工艺制取的人参籽油的脂肪酸组成。试验结果表明,在萃取压力26MPa、萃取温度50℃、萃取时间2 h工艺条件下,人参籽油得率为16.2%。经检测,人参籽油脂肪酸组成为不饱和脂肪酸占99%以上,其中油酸含量极高,可达73.93%。通过不同制取方法所得到的人参籽油的脂肪酸组成分析表明,超临界CO2萃取法与溶剂萃取法所提取人参籽油的脂肪酸明显多于压榨法的脂肪酸成分;且超临界CO2萃取法具有无有机化学试剂残留的明显优势,因此,是未来人参籽油提取中可以应用的一种绿色环保的提取工艺和技术。     

乙醇水剂法提取武夷水仙茶叶籽油及其品质分析

以武夷水仙茶叶籽为原料,采用乙醇水剂法提取武夷水仙茶叶籽油,通过单因素试验考察了提取温度、料液比、乙醇浓度和pH对提取率的影响,并采用正交试验设计优化了提取工艺条件.结果显示,武夷水仙茶叶籽油最佳提取条件为乙醇浓度30％(V/V)、料液比1:7、pH 9、提取温度60℃,在该条件下武夷水仙茶叶籽油提取率为93.61％....