新型双功能基环糊精单体制备

环糊精聚合物在分子识别、分离分析技术、生物医学工程、环境等领域得到越来越广泛应用;将环糊精分子转变成含有高反应基团单体,是制备环糊精聚合物一种有效途径。利用合理分子设计路线,通过β–CD磺酰化和氨基化反应得单6–乙二胺β–环糊精(β–CD–6–en),再与顺丁烯二酸酐通过胺解反应,制备既含双键又含羧基双官能团环糊精单体,并采用DSC、1H–NMR和IR对中间体和产物进行表征。     

Optimisation of Novozym‐435‐catalysed esterification of fatty acid mixture for the preparation of medium‐ and long‐chain triglycerides (MLCT) in solvent‐free medium

Novozym‐435‐catalysed esterification of caprylic acid, capric acid and oleic acid with glycerol for the synthesis of medium‐ and long‐chain triglycerides (MLCT) in vacuum and solvent‐free system was investigated in this study. Response surface methodology with a three‐level, four‐factorial design was applied to optimise the enzymatic esterification for the synthesis of MLCT. The optimum conditions were as follows: reaction temperature 90 °C, 4.80 wt% enzyme load (relative to the weight of total substrates) and substrate molar ratio (fatty acids/glycerol) of 3:1 and 12.37 h. Under above‐mentioned conditions, Triglycerides (TG) yield, MLCT and the residual free fatty acids (FFA) content in the product were 93.54%, 72.19% and 4.21%, respectively. The content of caprylic acid, capric acid and long‐chain fatty acids of TG was 24%, 10% and 66%, respectively. Novozym 435 in the study showed no selectivity for the different fatty acids and also could be used 14 times without obvious loss of enzyme activity.     

棉织物聚合-交联体系的酯化反应动力学

研究了对马来酸/衣康酸及马来酸聚合-交联体系的酯化反应动力学,按照一级反应的设定,分别计算了MA/IA和MA聚合-交联整理体系酯化反应的反应速率常数、活化能、频率因子等动力学参数.所得动力学数据能够较好地解释整理品性能的差异.     

Structural characterisation of β‐cyclodextrin crosslinked by adipic acid

This study was conducted to investigate the structural characterisation of β‐cyclodextrin (β‐CD) crosslinked by adipic acid. β‐CD was treated with different concentrations (0%, 5%, 10% and 15%, w/v) of adipic acid. Different instruments, such as scanning electron microsope (SEM), Fourier‐transform infrared (FT‐IR) spectroscopy and ¹H and ¹³C nuclear magnetic resonance (NMR) spectra were used to find out chemical structure in the crosslinked β‐CD. SEM analysis suggested that crosslinking β‐CD with 15% adipic acid changed the original morphology and considerably increased the particle size of the raw material. FT‐IR spectroscopy data showed that an intensive absorption band at 1706 cm^?1 was present in the β‐CD samples treated with 10% and 15% adipic acid, indicating a crosslinking between hydroxyl groups of β‐CD and carboxyl groups of adipic acid. NMR spectra revealed that the ester linkages between hydroxyl groups of β‐CD and carboxyl groups of adipic acid were formed after crosslinking of β‐CD with adipic acid.     

Chemical Modification of Pigskin Gelatin: Factors Affecting the Esterification of Gelatin with Fatty Acid

ABSTRACT: This study investigated the esterification of pigskin gelatin with fatty acid catalyzed by acid in aqueous medium. Factors affecting the esterification reaction B temperature, pH, water content, fatty acid concentration, fatty acid type and reaction time- were elucidated in the view of optimizing the reaction. Under the same experimental conditions, increase in fatty acid concentration permitted the determination of the maximum amount of fatty acid that could be esterified per unit weight of gelatin and demonstrated that not all the hydroxyl functional groups present in the gelatin could be blocked by the fatty acid chains.     

棉织物的马来酸寡聚物抗皱整理

OG系以马来酸为主体，添加柔性基团改性的多元羧酸寡聚物，将其应用于棉织物的抗皱整理，采用酸碱滴定法评价了其与棉织物的酯化交联情况。对不同反应温度、整理液浓度处理后-COOH的转化率进行比较分析，发现酯化度与折皱回复角之间存在一定的线性关系。结果表明，OG与BTCA及CA相比，更易与织物发生酯化反应，并可达到一定的抗皱效果。     

双端丙烯酰氧基聚醚硅油的制备及其改性聚丙烯酸酯性能

 采用丙烯酸和双端羟基聚醚硅油为原料,通过酯化反应制备了双端丙烯酰氧基聚醚硅油,研究了催化剂用量、反应温度和时间、溶剂和阻聚剂用量等因素对酯化率影响,用FTIR和1H-NMR对产物结构进行了表征;并将其应用于聚丙烯酸酯乳液制备,测定了改性乳液及其涂料印花性能。结果表明：酯化反应最佳条件为：催化剂和溶剂用量分别为反应物总质量的5%、70%,阻聚剂用量为丙烯酸质量的0.75%,反应温度为110℃,反应时间为4h;FTIR和1H-NMR谱图表明酯化产物结构为丙烯酰氧基聚醚改性硅油;改性乳液胶膜的疏水性变大,断裂强度略有下降,断裂延伸率明显变大,断裂功略有增加;改性乳液应用于涂料印花,印花织物干、湿摩可达4级及以上,手感柔软。     

Characteristics of Modified β‐Cyclodextrin Bound to Cellulose Powder

Monochlorotriazinyl‐β‐cyclodextrin (MCT‐β‐CD) was covalently bonded to cellulose powder. The amount of MCT‐β‐CD bonded to cellulose could be determined by infrared spectroscopy. The coupling reaction was characterized as a physical adsorption of the MCT‐β‐CD on the cellulose powder followed by an apparently zero order chemical reaction. The reaction rate constant was found to be k = 6.43 · 10^‐4 ± 0.11 · 10^‐4 g g^‐1 s^‐1. The immobilized cyclodextrin was able to include and release d‐limonene as a model flavor compound. The maximum molar inclusion ratio was 0.85, which is the same inclusion ratio as for d‐limonene in native β‐cyclodextrin. The release rates of dlimonene included in the fixed MCT‐β‐CD were monitored at various relative humidities and 50 °C. The release kinetics could be modeled using the Avrami equation. These results demonstrate that flavors as well as other hydrophobic compounds can be included and released from MCT‐β‐CD immobilized on cellulose.     

基于响应面分析的脂肪酶在黄水酯化中的应用研究

为提高白酒副产物黄水的使用价值,以黄水为原料,采用脂肪酶制剂酯化发酵生产白酒调味液原液。通过将一种纯脂肪酶制剂应用于黄水酯化过程,研究该脂肪酶制剂对于黄水酯化效果的影响,以总酯为响应值,在单因素试验基础上,选用己酸添加量,乙醇添加量和反应时间3个影响因子进行响应面优化试验。得到最佳条件为:己酸添加量1.69 mL/100 mL,乙醇添加量2.98 mL/100 mL,反应时间8.73 h。在该条件下,总酯值达到(5.071±0.08)g/L。     

Nanofibrillation of a Bleached Acacia Pulp by Grinding with Carboxymethylation Pretreatment

In this study,carboxymethylation,which introduces carboxyl groups to hydroxyl sites in pulp fibers,was used as a pretreatment before mechanical nanofibrillation.The carboxyl group content of the pulp fibers was greatly affected by the dosage of chloroacetic acid and the reaction temperature.During the following fibrillation process,it was found that pulp fibers with higher carboxyl group content exhibited higher water holding capacities and smaller dimensions.A more homogenous structure with a higher amount of individual fibrils was also observed in FE-SEM images of pulp fibers with high carboxyl group content.This can be explained by a high ionic group content in the fiber wall resulting in lower delamination resistance,making the fibrils easier to separate.Carboxymethylation pretreatment as a facilitator of fibrillation in cellulosic pulps is an efficient way to obtain cellulose nanofibrils and consequently decrease the energy consumption of the process.     

Selected functionality changes of beta-lactoglobulin upon esterification of side-chain carboxyl groups

Free carboxyl groups of bovine beta-lactoglobulin were esterified with methanol, ethanol, and n-butanol. The modified proteins showed increased positive charge as the number of ionizable carboxyl groups was reduced. The methyl, ethyl, and butyl esters of beta-lactoglobulin showed enhanced surface activity, determined with surface and interfacial tension measurements at an air/water and oil/water interface, respectively. The methyl ester showed the largest enhancement in surface activity relative to the native protein. The ethyl and butyl esters were less effective in lowering the surface and interfacial tension but were more surface active than the native protein. The hydrophobic probe, 1,8-anilinonaphthalene sulfonate, showed enhanced fluorescence in the presence of native and modified beta-lactoglobulin. The largest enhancement in fluorescence of the hydrophobic probe was noted in the presence of the methyl ester of beta-lactoglobulin. The ethyl ester also effectively enhanced the fluorescence of the probe. The slopes of the curves of the fluorescent response for the native and modified proteins were graphically related to the interfacial tension at an oil/water interface for the corresponding protein. A large positive correlation was noted between the effectiveness of the proteins in reducing the interfacial tension and the enhancement in fluorescence of ANS with hydrophobic binding by the proteins. A general method to quantify carboxyl groups of proteins, employing the formation of a colored hydroxamate-ferric ion chelate, was also developed. Modification of the reaction for proteins in general, and carboxyl-modified proteins in particular, appears to have potential. Use of the hydroxamic acid reaction made it possible to estimate the apparent extent of carboxyl modification of beta-lactoglobulin through esterification with methanol, ethanol, and n-butanol.     

Optimisation of kojic acid monolaurate synthesis with lipase PS from Pseudomonas cepacia

To improve the instability of kojic acid in food and cosmetic use, the esterification of kojic acid catalysed by lipase from Pseudomonas cepacia (Amano PS) to synthesise kojic acid monolaurate (KAML) was investigated in this study. Response surface methodology (RSM) with a five‐level/five‐factor central composite rotatable design (CCRD) was employed to evaluate the effects of synthesis parameters such as reaction time (8–24 h), temperature (35 55 °C), enzyme amount (10–50%), substrate molar ratio of lauric acid to kojic acid (1:1–3:1) and added water content (0–20%) on the percentage molar conversion to KAML by direct esterification. Reaction time and added water content were the most important variables, while substrate molar ratio had less effect on percentage molar conversion. Based on canonical analysis and ridge maximum analysis, optimal synthesis conditions were reaction time 19 h, temperature 44 °C, enzyme amount 38%, substrate molar ratio 2:1 and added water content 10%. The predicted value was 85% and the actual experimental value 82% molar conversion. © 2002 Society of Chemical Industry     

硫酸盐阔叶木浆中己烯糖醛酸及其含量的测定

阔叶木中大量存在的聚木糖的侧基团４ － Ｏ－ 甲基葡萄糖醛酸在硫酸盐法制浆中主要转化为己烯糖醛酸侧基（Ｈｅｘｅｎｕｒｏｎｉｃ ａｃｉｄ,简称ＨｅｘＡ） ,在纸浆中含量约５０ － ６０ｍｅｑ／ｋｇ。ＨｅｘＡ 的存在,对纸浆漂白有不利的影响：与亲电漂剂（ 如Ｃｌ２ 、ＣｌＯ２ 、Ｏ３ 和过氧酸） 发生反应,消耗一部分漂白药品;其六元环上的双键是Ｍｎ 等金属离子的重要的螯合部位;而且使得纸浆容易发生返黄。如果漂前对浆料进行适当的处理（ 如温和的酸水解） ,则可以选择性的去除大部分己烯糖醛酸,有利于后续的漂白。利用ＵＶ 光谱对ＨｅｘＡ 酸水解的主要产物２ － 糖酸进行测量,然后可以计算出己烯糖醛酸的含量。     

基于共价结合的纳米银抗菌棉织物研究进展

针对棉织物与纳米银之间缺乏亲和性,主要依靠物理吸附结合,水洗牢度差等问题,总结了基于共价结合的纳米银抗菌棉织物的最新研究进展,探讨了席夫碱反应和酯化反应这2种共价结合机制。以纳米银与棉织物之间的共价交联剂(超支化聚合物、树状大分子、丝素、丝胶、半胱氨酸、蛋氨酸、巯基乙酸、壳聚糖衍生物、聚苯乙烯-b-聚丙烯酸、丁烷四羧酸)种类进行分类介绍,结合抑菌率和银含量的数据讨论了基于共价结合的纳米银抗菌棉织物的制备工艺、抗菌性能和抗菌耐洗性能。最后对基于共价结合的纳米银抗菌棉织物领域存在的不足和未来需要深入关注的地方进行了探讨。研究指出,共价交联法大幅提高了纳米银的抗菌耐洗性能,为开发环境友好和长效抗菌的纳米银纺织品提供了新思路和新途径。     

机械活化协同微波法制备高取代度柠檬酸酯淀粉

在微波辐射条件下,以不同机械活化时间的木薯淀粉为原料,柠檬酸为酯化剂,氢氧化钠为催化剂制备柠檬酸酯淀粉。以取代度和反应效率为指标,分别探讨机械活化时间、微波功率、微波辐射时间、淀粉含水量、柠檬酸用量及氢氧化钠用量对木薯淀粉柠檬酸酯化反应的影响,并对影响因素进行了正交优化。结果表明,木薯淀粉经机械活化后,对微波功率、微波辐射时间、酯化剂用量、催化剂用量、淀粉含水量的依赖性明显降低,取代度和反应效率均为原木薯淀粉的2倍多。通过正交试验确定了制备柠檬酸酯淀粉的最佳工艺条件:微波功率800 W、微波辐射5.0 min、淀粉含水量35%、柠檬酸质量分数50%、氢氧化钠质量分数6%,所得产品的取代度为0.399 8,反应效率为88.84%。并采用红外光谱和X-射线衍射对木薯淀粉、活化淀粉及高取代度柠檬酸酯淀粉进行了表征。     

壳聚糖接枝改性单羧基棉织物的结构及性能

采用HNO3/H3PO4-NaNO2氧化体系选择性氧化棉织物得到单羧基纤维素,然后与壳聚糖溶液酰胺交联反应,使壳聚糖化学键合单羧基棉织物。研究HNO3/H3PO4-NaNO2氧化时间对单羧基棉织物羧基含量、断裂强力及壳聚糖接枝后棉织物增重率的影响,得出氧化时间在45min时,壳聚糖接枝棉织物的最大增重率为5.52%。运用固相CP/MAS 13C NMR、FT-IR、SEM和XRD等测试分析,结果表明,HNO3/H3PO4-NaNO2体系将棉纤维葡萄糖单元中C6位伯羟基选择性氧化成羧基,壳聚糖分子中的氨基与氧化棉织物上的活性羧基反应形成C-N酰胺化学键,壳聚糖在织物表面共价交联成膜。壳聚糖接枝反应后,单羧基棉织物的结晶度从65.37%下降到60.86%,壳聚糖改性棉织物的断裂强力、白度及毛细效应有所减小,但折皱回复角明显提高。     

微波辅助植物甾醇油酸酯的酶促催化合成

以candida rugosa脂肪酶为催化剂,采用微波辅助酶法合成植物甾醇油酸酯的研究。通过单因素和正交试验考察反应时间、微波功率、催化剂用量、料液摩尔比4个因素对植物甾醇油酸酯酯化率的影响,优化得出植物甾醇油酸酯的最佳合成工艺条件:反应时间36 min,微波功率550 W,催化剂用量9%,料液摩尔比4∶1。在此工艺条件下合成产物的酯化率为75.26%,经分离纯化后的产物纯度可达到91.19%。气相色谱-质谱及红外光谱检测分析结果表明微波辅助酶法合成产物为甾醇油酸酯。     

Optimization of omega-3 enriched-diacylglycerol production by enzymatic esterification using a response surface methodology

Incorporation of an eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) moiety into diacylglycerol (DAG) oil using lipase-catalyzed esterification was optimized using an ethyl ester form of EPA/DHA. A response surface methodology (RSM) was used to optimize reaction parameters (time, temperature, and substrate mole ratio) for incorporation of DHA and EPA into DAG oil. Predictive models for DHA+EPA contents of DAG and the amount of DAG produced after esterification were adequate and reproducible. DHA+EPA contents of DAG significantly increased with reaction time and substrate mole ratio (p<0.05). In contrast, the reaction temperature negatively affected the amount of DAG after esterification. Synthesis of DHA+EPA-enriched DAG was optimized for a maximum DAG content with the highest DHA+EPA content, in which 630.0 mg of DAG containing 34.8% DHA and EPA was predicted using the RSM model. The optimal reaction conditions were predicted at 20.6 h, 57.9 and a DHA/EPAenriched ethyl ester: DAG oil ratio of 2.5:1.     

Properties of cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin

The present study was designed to examine the physicochemical and sensory properties in cholesterol‐reduced Camembert cheese made by crosslinked β‐cyclodextrin (β‐CD). The composition of cholesterol‐reduced Camembert cheese was similar to the control and the cholesterol reduction reached 90.6%. No difference was found in the total amount of short‐chain free fatty acids between the cholesterol‐reduced cheese and the control at every ripening period. The release of butyric and capric acid mostly contributed to the increase of total amount of short‐chain free fatty acids in both groups. The cholesterol‐reduced cheese produced similar amounts of individual free amino acids to the control in all periods. The scores of all rheological characteristics except for springiness were continuously increased up to 2 weeks’ ripening and decreased thereafter. Mouldy characteristics in both appearance and flavour were increased dramatically through the ripening period in both cholesterol‐reduced and the control cheeses. Based on these results, no significant difference was found in most physicochemical and sensory properties between cholesterol‐reduced Camembert cheese and the control. Therefore, we may find it possible to develop cholesterol‐reduced Camembert cheese using crosslinked β‐cyclodextrin.     

Synthesis of high fatty acid starch esters with 1‐butyl‐3‐methylimidazolium chloride as a reaction medium

In this work, high fatty acid esters of corn starch were synthesized by reacting the starch with fatty acid methyl ester using 1‐butyl‐3‐methylimidazolium chloride (BMIMCl) ionic liquid (IL) as reaction media. The effect of reaction variables such as the catalyst amount, molar ratio of fatty acid methyl ester/anhydroglucose unit (AGU) in starch, pyridine/AGU molar ratio, reaction temperature, as well as reaction time on the degree of substitution (DS) of starch esters was investigated. The experimental results showed that the DS value of the obtained starch esters could be varied depending on the process conditions. In the optimum reaction condition, the achieved maximum DS of starch laurate and starch stearate was 0.37 and 0.28, respectively, at a reaction temperature of 110°C for starch laurate and 120°C for starch stearate for a reaction duration of 2 h. Furthermore, the starch esters were characterized by FTIR, SEM, and X‐ray diffractometry (XRD) techniques, respectively. Results from FT‐IR spectroscopy suggested that the hydroxyl groups in the starch molecules were converted into ester groups. SEM and XRD studies showed that the morphology and crystallinity of starch esters were disrupted largely in the IL medium under the reaction conditions.