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41.
精炼工艺对大豆油中微量物质变化的影响研究 总被引:1,自引:0,他引:1
植物油的精炼过程在除去不利于油脂稳定性的游离脂肪酸、过氧化物和磷脂及其他影响食用安全和油脂品质的物质同时,也造成油脂中微量营养物质的损失,以及一些新的有害物质的生成。研究了国内5个厂家的大豆油在精炼过程中微量物质的含量变化。结果发现,精炼后大豆油中生育酚及甾醇含量显著降低,分别由26.0~37.4 mg/100 g、402.75~841.92 mg/kg降为15.3~31.3mg/100 g、291.90~372.50 mg/kg,同时反式脂肪酸、聚合甘油三酯、缩水甘油酯含量分别提高到0.23%~1.85%、0.220%~0.738%、0.40%~2.94%。对精炼各工序中微量物质的含量进行显著性分析发现,除甾醇主要是在碱炼工序损失外,生育酚、反式脂肪酸、聚合甘油三酯及缩水甘油酯变化最显著均在脱臭工序。同时还考察了不同厂家各工序段的工艺参数,以期阐明大豆油精炼过程中微量物质的变化规律,为植物油适度精炼工艺的改进提供依据。 相似文献
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Canola flakes obtained before and after conventional cooking were extracted with supercritical carbon dioxide (SC-CO2) at 35–75°C and 20.7–62.0 MPa. Moisture content was adjusted to 12.7–42.5% (w/w, moisture-and oil-free basis). Moisture content of residual flakes after extraction was monitored. Amount of extract recovered increased with increasing temperature and pressure, except at 20.7 MPa pressure it decreased with temperature indicating a crossover of the solubility isotherms. Some water was co-extracted with canola oil. Free fatty acid (FFA) concentration of the extracts increased with decreasing pressure due to a decrease in triglyceride (TG) solubility. Oleic and linolenic acids had highest concentrations in the FFA fractions of all extracts. The lowest TG content of extracts was attained at 20.7 MPa and 75°C. The effect of extraction conditions was more pronounced than seed pre-treatments on yield and composition of SC-CO2 extracts. 相似文献
44.
以桑蚕蛹油为底物,通过酶法催化其与三辛酸甘油酯进行酯交换反应,制备富含α-亚麻酸的中长链脂肪酸甘油三酯(MLCTs)。通过单因素实验考察了酶种类、底物质量比、反应温度、加酶量以及反应时间对酯交换反应的影响,对酯交换条件进行了优化。结果表明,最佳反应条件为:采用Lipozyme TL IM脂肪酶,三辛酸甘油三酯与桑蚕蛹油质量比1∶ 4,加酶量为底物质量的8%,反应温度45 ℃,反应时间10 h。在最佳反应条件下,酯交换反应的转化率为98.42%,酯交换产物中中长链脂肪酸甘油三酯含量为98.73%,辛酸含量为20.00%,α-亚麻酸含量为30.09%。 相似文献
45.
J. Prasad RaoKurt E. Geckeler 《Progress in Polymer Science》2011,36(7):887-913
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M. Van Boven R. A. Holser M. Cokelaere E. Decuypere C. Govaerts J. Lemey 《Journal of the American Oil Chemists' Society》2000,77(12):1325-1329
Triglyceride compounds isolated from jojoba seed oil by column chromatography were composed predominantly of C18′ C20′ C22′ and C24 n−9 fatty acids with minor amounts of saturated C16. Chain length and double-bond positions were determined by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry
of the corresponding methyl ester and picolinyl ester derivatives. Triglyceride structures were analyzed directly by ion trap
mass spectrometry. The analysis of minor compounds, can provide highly specific information about the identity of an oil. 相似文献
48.
Feeding Tomatoes to Hamsters Reduces their Plasma Low-density Lipoprotein Cholesterol and Triglycerides 总被引:2,自引:0,他引:2
Hamsters were fed semipurified diets containing green or red freeze‐dried tomato powders. Compared to the control diet devoid of tomatoes, a 59% and 44% reduction low‐density lipoprotein (LDL) cholesterol was induced by both the green and red tomatoes, respectively. The corresponding reductions in very low‐density lipoproteins (VLDL) were 45% and 35% and in plasma triglyceride concentrations 47% and 31%, respectively. Plasma levels of high‐density lipoproteins (HDL) were unaffected. Fecal deoxycholic and lithocholic acid concentrations of hamsters on tomato diets were higher than those on control diets. Possible contributions of major components of green and red tomatoes to these beneficial effects are discussed. 相似文献
49.
Transesterification of rapeseed oil in the presence of basic zeolites and related solid catalysts 总被引:8,自引:1,他引:7
Elisabeth Leclercq Annie Finiels Claude Moreau 《Journal of the American Oil Chemists' Society》2001,78(11):1161-1165
The transesterification of rapeseed oil with methanol was performed by reflux of methanol over cesium-exchanged NaX faujasites,
mixed magnesium-aluminum oxides, magnesium oxide, and barium hydroxide for different methanol-to-oil ratios. Over cesium-exchanged
NaX faujasites and mixed magnesium-aluminum oxides, a long reaction time and a high methanol-to-oil ratio are required to
achieve both high oil conversion and high yields in methyl esters. However, over a 300 m2/g magnesium oxide, methanol-to-oil ratios and reaction times are significantly reduced to obtain both high oil conversion
and high yield in the methyl esters, particularly when the hydroxide precursor is calcined at 823 K. Finally, preliminary
results with other basic solids such as barium hydroxide have shown a very high activity and a very high yield in esters.
This catalyst is particularly effective since, for a methanol-to-oil ratio of 6, at reflux of methanol and after a reaction
time of only 1 h, the oil conversion is about 80% with a nearly quantitative ester molar fraction.
Part of this work was presented at the 91st AOCS Annual Meeting, San Diego, California, April 2000. 相似文献
50.