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11.
The effect of roasting on the phenolic components of Australian wattle (Acacia victoriae Bentham) seed was investigated. Wattle seeds were roasted at 200 °C for 5–30 min and ground to flour, which were then extracted with 70% acetone. The total phenolic and flavonoid contents of the extracts were determined, and the phenolic components were analysed by reverse phase-high performance liquid chromatography (RP-HPLC) coupled with an on-line post-column reaction system to determine the active antioxidant peaks. The major peaks were then purified by preparative HPLC and identified by gas chromatography–mass spectrometry (GC–MS) analysis. Roasting of wattle seeds resulted in significant increases in its soluble phenolic content. The concentration of total phenolics and flavonoids in the seeds roasted for 30 min was more than nine and four times higher, respectively, than that in the raw seeds. The major phenolic acids present in wattle seeds were found to be succinic and gallic acids, the concentration of which increased by up to 10-fold as a result of roasting. 相似文献
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Effects of oven-drying,roasting, and explosive puffing process on isoflavone distributions in soybeans 总被引:1,自引:0,他引:1
Distributions of isoflavones in soybeans treated with oven-drying, roasting, or explosive puffing were analysed using high-performance liquid chromatography (HPLC). As oven-drying time increased from 0 to 120 min at 100 °C, concentration (μmol/g) of malonyl derivatives of isoflavones decreased and β-glucosides increased significantly with over 0.99 coefficient of determination (R2) (P < 0.05). Roasting at 200 °C for 7, 14, and 21 min and explosive puffing at 490, 588, and 686 kPa decreased malonyl derivatives significantly and increased acetyl-β-glucosides and β-glucosides significantly (P < 0.05). Total isoflavones (TI) in 21 min roasted and 686 kPa puffed soybeans decreased by 25.46% and 10.42%, respectively, while TI in 120 min oven-dried soybeans was not significantly different (P > 0.05) compared to untreated samples. Regression analysis showed that malonyl-β-genistin had higher slopes of decreases (μmol/g/min) than malonyl-β-daidzin in oven-dried soybeans. This is the first report on the effects of explosive puffing and the changes of isoflavone profiles in soybeans. 相似文献
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用针铁矿法从锌焙烧烟尘的热酸浸出液中除铁 总被引:4,自引:1,他引:4
研究了从锌焙烧烟尘常压热酸浸出液中沉淀针铁矿的过程。试验结果表明,反应时间和空气流量对除铁率的影响不显著,而反应温度和溶液终点pH是除铁过程的主要影响因素。在终点pH3.0、反应温度333 K、反应时间2 h、空气流量0.2 m3/min的条件下,除铁率超过99.5%,溶液中铁浓度可由40g/L降至0.1 g/L以下。 相似文献
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从稀土精矿中提取稀土存在工艺复杂、对设备腐蚀严重、排放三废较多等问题.为了绿色而高效地利用稀土资源,将稀土精矿加氢氧化钙进行焙烧,考察油酸钠浮选体系中抑制剂种类对焙烧后稀土精矿(以REO单矿物表示)可浮性的影响.分别以焦磷酸钠、六偏磷酸钠、磷酸三钠、硅酸钠为无机抑制剂,以柠檬酸、乳酸、酒石酸为有机小分子抑制剂,以玉米淀粉、羧甲基纤维素钠、叔氨基阳离子醚化淀粉、羧甲基淀粉钠为有机高分子抑制剂,考察不同种类抑制剂对REO单矿物浮选行为的影响.结果表明:仅柠檬酸和焦磷酸钠对REO有明显的抑制作用,磷酸三钠和六偏磷酸钠对REO有微弱的抑制作用;焦磷酸钠在整个pH范围内对REO都有很强的抑制作用;柠檬酸对REO的抑制作用受pH值的影响,pH<8时抑制作用较强,REO基本上不浮,8相似文献
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《中国稀土学报(英文版)》2022,40(7):1134-1147
In this study, the Bayan Obo rare earth concentrates mixed with Na2CO3 were used for roasting research. The phase change process of each firing stage was analyzed. The kinetic mechanism model of the continuous heating process was calculated. This study aims to recover valuable elements and optimize the production process to provide a certain theoretical basis. Using X-ray diffraction (XRD), Fourier infrared spectroscopy, scanning electron microscopy with energy dispersive spectrometry, the reaction process and the existence of mineral phases were analyzed. The variable temperature XRD and thermogravimetric method were used to calculate the roasting kinetics. The phase transition results show that carbonate-like substances first decompose into fine mineral particles, and CaO, MgO, and SiO2 react to form silicates, causing hardening. Further, REPO4 and NaF can directly generate CeF3 and CeF4 at high temperatures, and a part of CeF4 and NaF forms a solid solution substance Na3CeF7. Rare earth oxides calcined at a high temperature of 750 °C were separated to produce Ce0.6Nd0.4O1.8, Ce4O7, and LaPrO3+x. Then, BaSO4, Na2CO3, and Fe2O3 react to form barium ferrite BaFe12O19; the kinetic calculation results show that during the continuous heating process, the apparent activation energy E reaches the minimum in the entire reaction stage in the temperature range of 440–524 °C, and the reaction order n reaches the maximum, which indicates that the decomposition product REFO significantly impacts the reaction system and reduces the activation energy. The mechanism function is F(α) = [?ln (1?α)]1/3. The reaction order n reaches the minimum in the temperature range of 680–757 °C, and the apparent activation energy E is large. The difficulty of the reaction increases during the final stage. The reaction mechanism function is F(α) = [1?(1?α)1/3]2. Observing the entire reaction stage, the step of controlling the reaction rate changes from random nucleation to three-dimensional diffusion (spherical symmetry). 相似文献
20.
《Ceramics International》2023,49(3):4855-4862
Zirconia is an inorganic, nonmetallic material with excellent properties. However, the brittleness of the zirconia, resulting from the thermal performance during the heating and cooling process, seriously limits the application of zirconia in the metallurgical, military, and aerospace industries. Al2O3 doped ZrO2 was developed to improve the potential material's toughness. This paper studied the evolution of the surface functional groups, phase composition, toughening mechanism, and particle morphology of Al2O3 doped ZrO2 during the heating process. Especially microwave heating was selected as the heating method during the experiments to save energy consumption. The results showed that the phase transition temperature was reduced by the microwave sintering technique, which also promoted the transformation between the m-ZrO2 and t-ZrO2, advancing the crystallinity and structural properties of the samples. The specific surface area shows a positive relationship with the microwave heating temperature, while the particle size of the powder decreased with the temperature increase. The optimized sintering effect appears at 1000 °C in the studied roasting temperature range (800 °C–1200 °C) for Al2O3–ZrO2 powders. With the optimized sintering temperature, the void of the granular zirconia material was controlled, and the best micromorphology was obtained. In practical production, the application of microwave sintering and alumina doping is beneficial to saving costs and protecting the environment. 相似文献