酸碱法纯化红三叶草中总异黄酮的工艺研究

采用酸碱法及醇溶水沉法对红三叶草中总异黄酮进行了纯化工艺的研究,分别考察碱溶pH、酸沉pH、水沉加水量对异黄酮含量及浸膏得率的影响。再通过正交实验得到最佳纯化工艺为：碱溶的pH为8.5,酸沉的pH为2.5时,加水量为6倍量时,异黄酮含量可达50%以上。     

基于碱溶酸沉法的亚麻籽油蛋白分离工艺优化

将亚麻籽油作为原料,选择碱溶酸沉法进行蛋白分离。先基于胶酶法对亚麻籽油进行脱胶预处理,在粉碎脱脂之后,通过碱溶酸沉法,进行亚麻籽油蛋白分离工艺优化,从提取pH、料液比、时间、温度四要素对其在亚麻籽油蛋白分离提取率中的影响做了详细分析。通过研究证明,亚麻籽油蛋白分离工艺的最佳参数为:提取液pH=9.5;温度50℃;料液比1∶30;时间为60 min,在此工艺条件下,蛋白分离提取率高达51.66%,蛋白质量分数高达92.28%。     

微生物发酵法制备的豆粕中大豆分离蛋白提取

采用碱提酸沉法对微生物发酵法制备的豆粕中提取大豆分离蛋白,并用凯氏定氮法测算大豆分离蛋白含量。研究碱提温度、液固比和碱提p H值及酸沉温度、时间和p H值对大豆分离蛋白提取率的影响。结果表明碱提的最佳工艺条件为:温度50℃、时间50 min、液固比10∶1、p H=9.0。酸沉的工艺参数为:温度45℃、时间40 min、p H=4.5。所得大豆分离蛋白最高提取率为79.29%。     

腐殖酸对钴、镉作用的研究

采用碱溶酸沉法提取土壤中的腐殖酸,研究其对Co2+、Cd2+的吸附作用机理。结果表明,最佳pH值为6～7,吸附过程属于放热过程。该腐殖     

调节pH纯化磺胺间甲氧嘧啶的工艺探讨

磺胺间甲氧嘧啶是一种人工合成、在兽医临床上使用最广泛的高效抗菌药之一。某公司磺胺间甲氧嘧啶生产线所得产品含量为74%～76%,常规手段纯化困难。磺胺间甲氧嘧啶结构含有伯氨基、磺酰胺基团,表现出酸碱两性,利用碱溶酸沉法通过调节反应溶液的pH,改变磺胺间甲氧嘧啶在水溶液中溶解度(存在状态),将反应杂质与磺胺间甲氧嘧啶分离,达到纯化的目的。实验结果显示:磺胺间甲氧嘧啶的产率与介质溶液的pH密切相关,在8.0～10.0区间内随pH的升高而增大,但纯度则相反。在pH=8.5～9.0范围进行调节,可以得到纯度在95%以上且产率满意的结果。     

大豆蛋白质的提取技术的研究进展

大豆蛋白质含有人体所必需的八种氨基酸,并具有优良的食品性能和营养价值,是一种重要的植物蛋白,在食品工业中得到了广泛的应用,是近年来的研究重点。其中,大豆蛋白的提取方法有碱溶酸沉法、酶解法、乙醇提取法、离子交换法、超滤膜分离法、发酵法等等。本文以研究方向和工艺改进两方面为着力点综述了碱溶酸沉法和酶解法这两种主要的提取方法的发展脉络。     

基于液气射流技术改进单宁酸氧化制备鞣花酸的工艺

针对鞣花酸在实际生产过程中耗时长、纯度低等问题，以单宁酸为基质采用液气射流氧化法制备鞣花酸，考察了金属离子、单宁酸浓度、反应温度和反应时间对鞣花酸得率及纯度的影响。进一步探究了溶剂法、结晶法、碱溶酸沉法、反溶剂法对鞣花酸纯度的影响，并通过高效液相色谱、红外光谱、紫外可见分光光谱和热重对鞣花酸高纯度的样品进行表征。结果表明，其制备的较优工艺条件为：2.5%单宁酸溶液中引入金属离子Na （即NaOH）调节反应液pH至8.5，反应温度20℃，反应时间6 h，该条件制备的鞣花酸经碱溶酸沉后产率为46.72%、纯度84.55%；选取甲醇溶剂洗涤法在65℃条件下处理1h，鞣花酸的纯度达98.13%，回收率为75.03%，提高了鞣花酸的热稳定性。液气射流氧化法与溶剂洗涤法相结合，大幅缩短制备鞣花酸的反应时间并明显提高其纯度，有望在工业生产中提高鞣花酸的生产效率并拓宽其在医药和化妆品领域的应用。     

高纯偏钒酸钾制备工艺研究

以偏钒酸铵为原料,采用碱溶除杂、浓缩脱氨、溶析结晶的方法,制备的偏钒酸钾产品纯度大于99.5%。分析了制备过程的工艺原理,考察了pH、脱氨浓缩温度和钒浓度对偏钒酸钾成分的影响,探讨了溶析结晶的工艺条件。结果表明,影响偏钒酸钾质量的主要因素是碱溶除杂的pH和浓缩终点pH。制备过程的最佳工艺条件为：碱溶除杂pH为9~10、脱氨温度为95 ℃、浓缩终点pH为7.5~8.5、浓缩终点总钒质量浓度为180 g/L、溶析剂与溶液体积比为1∶1、结晶时间为30 min。滤液中残留的钒质量浓度低于3.0 g/L,钒收率达到98%以上。     

液气射流技术改进单宁酸氧化制备高纯度鞣花酸

针对鞣花酸在实际生产过程中耗时长、纯度低等问题,以单宁酸为基质采用液气射流氧化法制备鞣花酸,考察了金属离子、单宁酸质量浓度、反应温度和反应时间对鞣花酸得率及纯度的影响.进一步探究了溶剂法、结晶法、碱溶酸沉法、反溶剂法对鞣花酸纯度的影响,并通过HPLC、FTIR、UV-Vis光谱和TG对鞣花酸高纯样进行表征.得到液气射流氧化的较优工艺条件为:质量浓度25 g/L单宁酸溶液中引入金属离子Na+(即NaOH)调节反应液pH至8.5,反应温度20℃,反应时间6 h.该条件制备的鞣花酸经碱溶酸沉后收率为46.72％、纯度84.55％;采用甲醇溶剂洗涤法在料液比1:200(g:mL)、65℃下处理1 h,鞣花酸的纯度达98.13％,回收率约为75.03％,提高了鞣花酸的热稳定性.液气射流氧化法与溶剂洗涤法相结合,大幅缩短制备鞣花酸的反应时间并明显提高其纯度,有望在工业生产中提高鞣花酸的生产效率并拓宽其在医药和化妆品领域的应用.     

Box-Behnken响应面法优化阿里红总多糖水提醇沉工艺

分别采用单因素实验和Box-Behnken响应面法对阿里红总多糖水提醇沉工艺条件进行优化。以苯酚-硫酸法测定阿里红总多糖含量,在单因素实验基础上,选择多糖提取率为评价指标,以浸泡时间、提取时间、加水倍量作为考察因素,采用Box-Behnken响应面法优化水提工艺条件;选择多糖含量为评价指标,以醇沉浓度、醇沉时间、浓缩倍数为考察因素,采用Box-Behnken响应面法优化醇沉工艺条件;采用Sevage法对阿里红粗多糖进行脱蛋白。得到最佳水提工艺条件为:加水10倍,浸泡时间1.5 h,提取1.0 h,提取1次;最佳醇沉工艺条件为:浓缩倍数10倍,醇沉浓度80%,醇沉时间12 h;Sevage法脱蛋白,蛋白脱除率为42.4%,多糖保留率为61.4%。建立的阿里红总多糖提取纯化工艺简单可靠。     

Adsorption and Desorption Behavior of Tannic Acid in Aqueous Solution on Polyaniline Adsorbent

Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8-6.7. Coexisting cations, such as Na⁺, K⁺, and Ca²⁺, can enhance the adsorption of tannic acid on polyaniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorption process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 mg·g^-1 at 35℃ and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the adsorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.     

Crystallization of alkaline protease as a means of purification process

A purification protocol of alkaline protease purification using crystallization was developed by investigating the effects of pH, temperature, initial enzyme concentration, salt (as crystal inducer) concentration, and the presence of impurity proteins. A commercial alkaline protease solution was used as a starting material and NaCl was used as a crystal inducing salt. The crude enzyme solution was first diafiltered against deionized water and then concentrated by ultrafiltration. To the enzyme concentrate appropriate amount of NaCl was added to induce the crystallization which was lasted for 24 hours, and the enzyme crystals formed were filtered and washed with deionized water before being resolubilized. Crystal habit was typical needle shape, and the reaction order of its formation was estimated to be 1.53. The crystallization was strongly influenced by initial enzyme concentration. Solubility of alkaline protease at 25°C was 24.8 mg/ml, which was about one half of that of 4°C. Enzyme recovery yield of the purification process including the crystallization step ranged 50 to 60 %. The crystallization step was shown to successfully exclude impurity proteins from their habits as evidenced by gel permeation chromatography. The optimum condition for the crystallization was: pH 9.0, 25°C temperature, ca. 53 mg/ml or higher enzyme concentration, and minimum 5 % (w/w) NaCl concentration. In summary, an enzyme purification protocol based on crystallization was established, which can be applied to obtain a higher-purity alkaline protease solution on a large scale.     

由玉米提取菲汀的研究

由玉米浸泡水提取菲汀,最适宜的条件是:酸浸液的 pH值为 2～3,碱沉液的 pH值为 6,在最佳条件下菲汀的收率为1.1～1.2％。     

超声空化合成安息香

采用超声空化、相转移催化法,用水/乙醇为反应介质,以苯甲醛为原料,盐酸硫胺（VB1）为催化剂,在碱性溶液中反应制得安息香。对原料配比、反应温度、反应时间、体系pH值、相转移催化剂的种类等各种反应条件的影响作了详细的研究。实验得到最优条件为：乙醇/水二元混合溶液中,苯甲醛5 mL,盐酸硫胺2.0 g,相转移催化剂用量占苯甲醛质量的百分比为10%~12%,蒸馏水量2 mL,乙醇量8 mL,体系的pH值控制在9.3~9.7之间,水浴超声空化控温在70℃左右,反应时间90 min,超声功率80%。最优条件下收率达到93.57%,产品含量在90%以上。该工艺具有反应条件温和、转化率较高等优点。     

阳离子褐煤树脂的阳离子度测定方法研究

采用四苯硼钠电位滴定法测定阳离子褐煤树脂的阳离子度.通过消除测定方法的离子干扰、优化四苯硼钠电位滴定法的测定条件来提高测定方法的准确度.采用5％盐酸溶液提取阳离子腐植酸,去除钾离子和其他水溶性杂质;四苯硼钠电位滴定过程中,提纯后阳离子腐植酸加入量为0.5g,用0.2％氢氧化钠溶液溶解阳离子腐植酸,在pH 10.0条件下,选用甘汞电极为参比电极,氟硼酸根离子选择性电极为指示电极,用十六烷基三甲基溴化铵标准溶液电位滴定四苯硼钠,电位突变约200 ～300 mV,加标回收率达95％,满足分析测试的要求.实验结果表明,该方法选择性好、准确性高、易于操作,具有较高的推广应用价值.     

Synthesis and flocculation behavior of cationic konjac glucomannan containing quaternary ammonium substituents

A quaternary ammonium derivative of konjac glucomannan (KGM) was prepared by a dry process from KGM and 2,3‐epoxypropyl trimethylammonium chloride. We determined the optimization of the experimental conditions by studying on the effects of the water amount, alkaline catalyst amount, reaction temperature, and reaction time on the degree of substitution. In addition, the flocculation characteristics of the cationic derivative of KGM were evaluated in a 1.0% kaolin suspension with spectrophotometry via investigation of the influence of the flocculant amount, pH, salt concentration, temperature, and settling time on the flocculation. The results show that the synthesized cationic KGM could potentially be used as a high‐performance flocculating agent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Deep Purification of Zinc Ammoniacal Leaching Solution

Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.     

Deep Purification of Zinc Ammoniacal Leaching Solution by Cementation with Zinc Dust

Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied.The effects of relative amount of metallic impurities,dosage of zinc dust,purification time,temperature,pH value and total ammonia concentration in the solution on the purification of the solution were investigated.The results indicate that total ammonia concentration in the solution had no effect on the purification,but relative amount of metallic impurities,dosage of zinc dust,purification time,temperature and pH value of the solution were the main factors influencing the purification.Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium.Nevertheless,the presence of cobalt went against the cementation of cadmium and cobalt.All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage,1 h of purification time,35℃,pH value 9.03 of zinc ammoniacal leaching solution.The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.     

两步法净化湿法磷酸及食品级磷酸氢钙的制备

采用两步脱氟和一步脱重金属与砷净化湿法磷酸 ,得到磷酸杂质含量为 :w(Pb) <0 0 0 1% ,w(F) <0 0 0 4% ,w(As) <0 0 0 0 2 % ,可作为食品添加剂使用。探讨了pH值、温度以及脱氟剂、脱重金属与脱砷剂用量等对净化效果的影响 ,得到第一步最佳净化工艺条件 :温度为 90～ 95℃ ,脱氟剂 (SiO2 )用量为磷酸中含F总质量的 12 0 % ;第二步最佳净化工艺条件 :pH值为3 0～ 3 2 ,温度为 10℃以下 ,脱氟剂 (SiO2 +Na2 CO3)组分SiO2 用量为第一步净化后磷酸中含F总质量的 2 5 0 % ,两组分的质量比m(SiO2 )∶m(Na2 CO3) =(5～ 10 )∶1,脱重金属与脱砷剂 (Na2 S)用量为磷酸中含重金属与砷总质量的 2 80 %。进一步净化磷酸制得了食品级磷酸氢钙。     

Effect of Extraction and Precipitation Conditions During Soybean Protein Isolate Production on the Genistein Series Content

The influence of the conditions for isolation of soy protein on the content of genistein and its conjugated forms was studied. The major components of the genistein series isolated from soybean flour were malonyl genistin (54.3%), genistin (36.9%), and equal amounts (4.4%) of genistein and acetyl genistin. A modification in the conjugation profile of genistein between pH 4.5 and 8.0 and above pH 10 was attributed to the action of β-glucosidase and the saponification reaction, respectively. A decrease in the content of total genistein in the insoluble flour residue and in the soy protein isolate (SPI) with increasing extraction pH was detected, while in the whey, the total genistein content was not affected by pH. The effect of pH variation during acid precipitation on the content of genistein and its conjugated forms, at a constant extraction pH (8.0), was also studied. Under these conditions, the highest absolute content of total genistein in the SPI was obtained at pH 3.5 and the lowest was obtained at pH 5.6. The total genistein content in the whey followed an inverse trend compared with that of the protein yield. A temperature increase did not substantially affect the distribution of the different genistein forms or their total contents. The content of total genistein was higher in the glycinin than in the β-conglycinin protein fraction. The effect of the pH during the alcohol/water extraction of the isoflavones was also analyzed. The efficiency of the extraction was lower at pH values between 3.25 and 3.5 than at other pH values.