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水库是我国防洪广泛采用的工程措施之一。在防洪区上游河道适当位置兴建能调蓄洪水的综合利用水库,利用水库库容拦蓄洪水,削减进入下游河道的洪峰流量,达到减免洪水灾害的目的。文章就水库存在的问题进行了简要的分析与讨论,并提出相应的解决措施,以便供其参考。 相似文献
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食用虾中虾青素类化合物的含量和组成 总被引:1,自引:0,他引:1
虾青素的抗氧化能力高于β-胡萝卜素、玉米黄质、角黄质、VC和VE,其防止大鼠线粒体脂质过氧化的功效是VE的100~500倍。本研究针对从北京市场购买的五种食用虾,应用UV-VIS和C30-PDA-HPLC的检测方法,对其中虾青素含量和组成进行分析。结果表明:此五种虾的虾壳中,虾青素单体和酯含量较高,虾肉中的含量相对较少。在价格昂贵的澳洲龙虾肉中未检出虾青素,而南美白对虾肉中的虾青素含量较高。常见虾的壳呈暗蓝色或青灰色,但有些龙虾的壳(部分或全部)呈现橘红色,其着色物质的组成有待进一步研究和比较。 相似文献
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该研究建立了高效液相色谱法测定虾青素油中虾青素含量的分析方法。利用单因素实验,对虾青素油中虾青素的提取试剂、酶解时间进行选择,确定最佳前处理条件为37℃恒温水浴振荡酶解60 min,石油醚提取。色谱条件:YMCTMC30色谱柱(250 mm×4.6 mm,5μm),柱温30℃,流动相为甲醇-甲基叔丁基醚梯度洗脱,流速1 mL/min,检测波长472 nm。结果表明,全反式虾青素在0.10~4.00μg/mL范围内与峰面积有良好线性关系,精密度的相对标准偏差(relative standard deviation,RSD)为1.36%,表明精密度高,平均回收率为93.58%,回收率的RSD为2.84%,表明添加回收率高,相对标准偏差小,实验建立方法测得虾青素油中虾青素的含量为92.9%,是碱性皂化测得结果的2.11倍,所建立的方法可以准确定量虾青素油中虾青素的含量。 相似文献
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食品中虾青素的C18-HPLC-PDA分离与鉴定 总被引:1,自引:0,他引:1
在装备了二极管阵列检测器(PDA)的高压液相色谱(HPLC)上,应用C18柱,冰凉花和虾中的主要酮基类胡萝卜素-虾青素可以被分离。分离条件为:色谱柱为DiamonsilTM(5μm,4.6mm×25cm,DikmaTechnology);流动相A为乙腈-水(90∶10,V/V),用磷酸调pH3.0;流动相B为乙酸乙酯;线性梯度洗脱:B在15min内由0%增加至70%;15~25min内B维持在70%;流速=1.0mL/min;检测波长=480nm;PDA波长范围=280~580nm;进样量=20mL。根据其与参比样品的色谱行为和光谱特征比较,样品中的虾青素可被鉴定。它在C18-HPLC-PDA上的定量亦成为可能。 相似文献
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E Ilesanmi Adeyeye H Omolara Adubiaro 《Journal of the science of food and agriculture》2004,84(5):411-414
The protein, ash, fibre and individual mineral ion contents of three species of prawn taken from the Lagos lagoon were determined. The median liveweights of Macrobrachium vollenhovenii (Herklots), Palaemon species A (Powell) and Penaeus notialis were respectively, 25.52 g (shell + head 16.76 g; flesh 9.26 g), 3.15 g (shell + head 1.71 g; flesh 1.44 g) and 5.11 g (shell + head 2.14 g; flesh 2.96 g). All (shell + head) samples had high protein, ash and fibre contents but only the protein content was high in the flesh, which had low or undetectable quantities of fibre. The fat and carbohydrates contents were generally low. In M vollenhovenii the (shell + head) was a better source of Mg, Zn, Cu and K than the flesh, which was a better source of Ca, Ni, P, Fe, Co and Na. In P species A the (shell + head) was a better source of Ca, Mg, P, Cu, Co, Na and K than the flesh (higher in Zn and Ni). In P notialis the (shell + head) was the better source of Ca, Zn, P, Fe and Co and the flesh the better source of Mg, Ni, Fe, Na and K. Copyright © 2004 Society of Chemical Industry 相似文献
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《纺织学会志》2012,103(1):49-59
AbstractThe present study investigates preparation, characterization, and application of chitosan (Ch) and its derivative, carboxymethyl chitosan (CMCh), on jute and cotton fibres through the eco-friend modification avoiding chemical modifier. Chitosan is a deacetylated product of chitin. CMCh was produced from prepared chitosan (89% degree of deacetylation) by carboxymethylation process, and confirmed by Fourier transform infrared (FTIR) spectroscopy. CMCh had an average degree of substitution ranging from 0.62 to 1.20 was determined by titrimetric analysis. X-ray diffraction of CMCh showed a less ordered arrangement than chitosan. Moisture content and ash content of Ch and CMCh were 10%, 9% and 2.33%, 14.39%, respectively which affect cellulosic fibre properties. Extracted chitosan and CMCh were used as surface modifier for natural cellulosic fibres. Modification of jute and cotton through sorption of chitosan and CMCh introduces amino (1610?cm?1) and carboxyl groups (1737?cm?1) on the cellulose chain of fibre surface, causes functionalization. The modified fibres were characterized by FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Again, dyed modified fibres showed 10–15% higher dye exhaustion, and better fastness properties than that of unmodified fibres. 相似文献
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研究核桃破壳壳仁分离加工成套设备壳仁混合物料气流分离系统运行参数对壳仁分离效果的影响,为实际生产中成套设备气流分离系统调节与运行参数选择提供依据。以仁中含壳率和壳中含仁率为指标,在单因素试验的基础上,通过正交试验确定核桃壳仁混合物料气流分离系统的运行参数。结果表明:调节阀开度对壳仁分离效果影响最显著,卸风板开度影响次之、喂料速度影响最小。核桃壳仁混合物料气流分离最优运行参数为:调节阀开度1/2、1/4、1/8壳仁30°,1/16壳仁15°,两组分心木15°;卸风板开度1/2壳仁30°,1/4、1/8、1/16壳仁15°~30°,两组分心木30°~45°;喂料速度1/2、1/4、1/8、1/16壳仁分别为6、2、1、0.35 kg/min。在最优运行参数下,1/2、1/4、1/8、1/16壳仁的仁中含壳率分别为2.26%、1.07%、3.61%、5.57%,壳中含仁率分别为0.88%、054%、3.92%、6.85%。实际生产中建议整套设备原果核桃加工生产能力控制在600 kg/h以内。 相似文献
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目的:对小米混菌发酵过程中酵母菌对乳酸菌生长代谢的影响加以研究,并建立混菌发酵生长动力学模型.方法:以小米为生长基质,将乳酸菌和酵母菌分别纯培养和混菌培养,研究发酵液中细胞浓度、游离氨基氮(FAN)、还原糖、乳酸及乙醇含量的变化;在对Lotka-Voherra种间竞争模型改进的基础上构建混菌发酵生长模型,利用origin软件求解参数并对模型进行拟合验证.结果:加入辅助菌株酵母菌进行混菌发酵,酵母菌对乳酸菌的生长有促进作用,但对其发酵产酸没有产生显著影响,乳酸菌的存在对酵母菌有一定的抑制作用,但酵母菌主要产物乙醇的产量却显著增加;混菌发酵生长模型求得的预测值与实测值拟合较好,该模型可以有效预测混菌培养过程中乳酸菌和酵母菌的生长. 相似文献