柠檬酸酯淀粉最佳制备条件的研究

以玉米淀粉为原料,采用酯化变性的方法,在干法条件下制备高取代度柠檬酸酯淀粉,探讨反应时间、反应温度、pH值、柠檬酸浓度对淀粉酯化过程的影响。结果表明,高取代度柠檬酸酯淀粉的最佳制备条件为反应时间7h、反应温度130℃、pH为3.0、柠檬酸浓度为45%。     

高取代度柠檬酸酯淀粉的制备

柠檬酸酯淀粉是一种具有抗性作用的酯化变性淀粉。在国外广泛地应用于面包、饼干及其他食品中以改善食品的品质。本文以玉米淀粉为原料，采用酯化变性的方法，在干法条件下制备高取代度柠檬酸酯淀粉。探讨了反应时间、反应温度、pH值、柠檬酸浓度对淀粉酯化过程的影响。通过试验研究得到了各种因素变化时，产品取代度的变化趋势，为进一步优化制备条件提供了依据。     

柠檬酸酯淀粉的制备

柠檬酸酯淀粉是一种具有抗性作用的酯化变性淀粉，广泛地应用于面包，饼干及其他食品中，以改善食品的品质。本文以玉米淀粉为原料，采用酯化变性的方法，在干法条件下制备高取代度柠檬酸酯淀粉，探讨了反应时间、反应温度、pH值、柠檬酸浓度对淀粉酯化过程的影响。通过实验研究得到了各种因素变化时。产品取代度的变化趋势，为进一步优化制备条件提供了依据。     

柠檬酸酯淀粉中抗性含量的测定及制备条件的研究

柠檬酸酯淀粉是一种具有抗性作用的酯化变性淀粉。在国外广泛地应用于面包,饼干及其他食品中以改善食品的品质。本文以玉米淀粉为原料,采用酯化变性的方法,在干法条件下制备了柠檬酸酯淀粉,并测定出了其中的取代度、反应效率和抗性含量。着重探讨了反应时间﹑反应温度﹑柠檬酸用量对产品抗性含量的影响。     

低取代度淀粉丁二酸酯的制备

以玉米淀粉为原料,丁二酸酐为酯化剂,以水为媒介,氢氧化钠为催化剂对低取代度淀粉丁二酸酯的制备工艺进行了研究.考察了丁二酸酐用量、反应时间、反应温度、反应pH值对低取代度淀粉丁二酸酯取代度的影响.实验结果表明,丁二酸酐用量增大,淀粉丁二酸酯取代度随之增加;反应时间、反应温度和反应pH值对淀粉丁二酸酯取代度的影响曲线呈抛物线形状,存在较佳值,较佳工艺条件为:反应时间50 min、反应温度30℃、反应pH值9.0;玉米淀粉经酯化后,其糊化温度降低,糊液透明度提高,糊液黏度增大.采用酸碱滴定法测定淀粉丁二酸酯的取代度.以水为媒介,制备低取代度淀粉丁二酸酯方法可行.     

活化处理方法对制备柠檬酸淀粉酯的影响

采用三种不同方式预先对淀粉进行活化,然后以活化淀粉为原料,以柠檬酸为酯化剂制备柠檬酸淀粉酯。探讨了活化方式、原料配比、催化剂用量、反应温度及反应时间对淀粉酯化取代度的影响。对淀粉柠檬酸酯的糊化透明度及乳化效果进行测试。结果表明,胰酶活化对淀粉酯化效果影响较显著。柠檬酸淀粉酯的最佳合成条件是:淀粉柠檬酸质量比2∶1,催化剂为淀粉质量的3%,反应时间5h,反应温度70℃时,制备的淀粉酯取代度为0.412。随着淀粉酯取代度增大,淀粉糊透明度升高,乳液稳定性先升高后稍有回落。     

辛烯基琥珀酸交联淀粉酯合成工艺研究

以木薯淀粉为原料,用环氧氯丙烷作交联剂,辛烯基琥珀酸酐作酯化剂,采用湿法工艺合成辛烯基琥珀酸交联淀粉酯.探讨了淀粉乳浓度、反应温度、反应时间、pH和沉降积对辛烯基琥珀酸交联淀粉酯取代度的影响,确定制备辛烯基琥珀酸交联淀粉酯的最佳工艺参数为:淀粉乳浓度35%,酯化pH 8.0,酯化温度35℃,酯化时间3 h.交联淀粉的沉降积对酯化取代度影响较小,在生产中可根据最终产品的用途选用合适沉降积的交联淀粉进行酯化复合变性.复合变性淀粉符合食品行业标准,可以在食品工业中应用.扫描电镜对其结构进行观察显示淀粉中受侵蚀颗粒增多,颗粒表面的小凹痕数量增加.     

柠檬酸甘薯淀粉酯制备工艺优化及性质研究

以甘薯淀粉为原料,优化制备高取代度柠檬酸淀粉酯的条件并对其性质进行研究。以柠檬酸淀粉酯取代度为指标,对影响取代度的因素进行研究,通过响应面优化制备工艺。得到最优工艺条件为pH1.5、反应温度148.21℃、反应时间6.45h、柠檬酸与淀粉干基质量比为0.59,在此条件下可制得取代度高达0.30的柠檬酸甘薯淀粉酯;柠檬酸甘薯淀粉酯具有很好的抗酶解性,抗性淀粉含量随取代度的增加而增加,当取代度达0.13时,抗性淀粉含量达92%;对比原淀粉,柠檬酸甘薯淀粉酯平均聚合度降低,白度先增高后降低。     

植酸淀粉酯的制备工艺研究

以植酸钠为改性剂，对马铃薯淀粉进行了酯化改性。以植酸钠的取代度为指标，确定了植酸淀粉酯制备的最佳条件为：植酸钠用量2％，pH7，淀粉乳浓度30％，反应时间5．5h，反应温度50±5℃。     

制备条件对木薯淀粉醋酸酯取代度的影响

以木薯淀粉为原料,醋酸酐为酯化剂制备淀粉醋酸酯,考察制备条件对取代度的影响.实验结果标明:取代度随反应体系pH升高而增加,在pH9时达到最高值,之后下降;温度升高,取代度随之上升,35 ℃后升高趋势减缓;取代度在反应时间为1.5 h时最高,延长反应时间取代度因酯水解而降低;随酯化剂用量增加,淀粉醋酸酯的取代度不断升高.     

Development and Physicochemical Characterization of New Resistant Citrate Starch from Different Corn Starches

Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high‐amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High‐amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC thermogram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the thermograms. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the thermograms when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.     

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。     

Studies on the properties of citrate derivatives of cassava (Manihot esculenta Crantz) starch synthesized by microwave technique

Cassava starch citrates with degree of substitution (DS) ranging from 0.005 to 0.063 were synthesized by the microwave‐assisted reaction of cassava starch with citric acid. A response surface small composite design was used to study the effect of different reaction conditions, viz. time, temperature and reagent concentration. All these variables significantly affected the substitution level in the modified starches. The DS increased with increase in the time of reaction and temperature. However, reagent concentration had a negative effect on the DS. The modified starches showed higher viscosity with lower breakdown, lower setback and higher final viscosities in comparison to native starch. Differential scanning calorimetry showed that the modified starches exhibited a decrease in gelatinization temperatures, T_o, T_p, T_e, in comparison to native starch. However, the heat of gelatinization was not significantly affected. The citrate derivatives exhibited reduced swelling volume and enhanced water binding capacities. They were found to be less susceptible to enzyme hydrolysis than native starch. Copyright © 2007 Society of Chemical Industry     

槲皮素-羧甲基甘薯淀粉酯的合成

以甘薯淀粉为原料,依次经过羧甲基化、槲皮素共价修饰两步改性,得到槲皮素-羧甲基甘薯淀粉酯,并采用单因素及响应面试验考察制备工艺条件对产物取代度的影响。单因素试验结果表明,其取代度随反应底物配比（N槲皮素/AGU）（X1）的增加而增加,随活化试剂与羧甲基甘薯淀粉脱水葡萄糖基的物质的量比（NEDC/AGU）（X2）及反应体系pH值（X3）的增加呈先增加后降低的趋势;响应面试验结果表明,NEDC/AGU及反应体系pH值对取代度有极显著影响（P＜0.01）,而N槲皮素/AGU以及二次项和交互项对取代度的影响不显著（P＞0.05）。得到最佳工艺条件为羧甲基甘薯淀粉质量浓度51?g/L、N槲皮素/AGU?2∶1,NEDC/AGU?1.8∶1、反应体系pH?7.4,可制得最大取代度（0.114?9）的槲皮素-羧甲基甘薯淀粉酯。通过检测槲皮素从产物的水解释放确认产物的合成。     

Cationisation of Glycerol Plasticised Wheat Starch under Microhydric Molten Conditions

Cationisation of glycerol plasticised wheat starch was performed in a molten mixture under the action of thermo‐mechanical energy using two reagents: 3‐chloro‐2‐hydroxypropyltrimethylammonium chloride and 2‐epoxypropyltrimethylammonium chloride. The reaction was catalysed with sodium hydroxide under microhydric conditions. The results showed that under these conditions the reaction proceeds rapidly and reaches completion within a few minutes. The reaction efficiencies were higher for lower degrees of substitution (DS). The epoxide showed a higher reactivity than the chloro derivative. Both destructurisation of starch granules and increased sodium hydroxide concentration enhanced the reaction, but an increase in plasticiser concentration had a negative effect. Measurements of intrinsic viscosity showed a decrease of the average molecular weight of the product, which was attributed to the thermo‐mechanical melting process. An increase in water affinity with DS was seen in the water sorption properties of the chemically modified starch.     

制备荞麦羧甲基淀粉的研究

研究了以荞麦淀粉为原料，用乙醇溶剂法制备荞麦羧甲基淀粉(CMs)。探讨了淀粉乳浓度、一氯乙酸用量、氢氧化钠用量、反应体系水分含量、反应温度和反应时间对荞麦羧甲基淀粉取代度(Ds)的影响，通过正交试验，确定制备荞麦羧甲基淀粉最优工艺条件。     

低取代度阳离子淀粉-丙烯酰胺接枝共聚物的制备及应用

以低取代度的阳离子淀粉为原料,硝酸铈铵为引发剂,制备了低取代度阳离子淀粉-丙烯酰胺接枝共聚物。研究了丙烯酰胺与阳离子淀粉质量比、反应温度、反应时间和引发剂浓度对接枝率和接枝效率的影响。结果表明:接枝率和接枝效率最高的条件为:m(丙烯酰胺)∶m(阳离子淀粉)=2.5∶1,反应温度为55℃,反应时间为3 h,c(引发剂)=2 mmol/L。将合成的聚合物用于纸张增强,当低取代度阳离子淀粉-丙烯酰胺接枝共聚物的用量为1.0%时,对纸张的增强效果最好,可使纸张抗张指数增加23.0%,撕裂指数增加12.7%,耐破指数增加63.7%,耐折度增加115.1%。     

乙酰化辛烯基琥珀酸蜡质玉米淀粉酯的制备及性质研究

以蜡质玉米淀粉为原料,选取乙酸酐和辛烯基琥珀酸酐对其进行双重酯化改性,以取代度为衡量标准,确定了蜡质玉米双重酯化淀粉的制备顺序是先进行乙酸酐的乙酰化再进行辛烯基琥珀酸酐的酯化,得到产物乙酰化辛烯基琥珀酸蜡质玉米淀粉酯。按照确定好的酯化顺序,以实验室自制取代度为0.0768的乙酰化淀粉为原料,采用单因素和正交实验的方法研究湿法工艺制备乙酰化辛烯基琥珀酸蜡质玉米淀粉酯,得出最佳工艺条件为:在辛烯基琥珀酸酐加入量为3%的情况下,淀粉乳初始浓度30%,反应体系pH8.5,反应温度35℃,反应时间4h。采用最佳工艺条件所得产品辛烯基琥珀酸酐酯化取代度为0.0197,利用红外光谱分析方法对乙酰化辛烯基琥珀酸蜡质玉米淀粉酯的结构进行了初步表征,并对产品的乳化性及乳化稳定性、透明度、表观黏度等性质做了测定和分析。     

Synthesis and Preparation of Crosslinked Allylglycidyl Ether‐Modified Starch‐Wood Fibre Composites

Native potato starch has been modified with allylglycidyl ether (AGE) under various reaction conditions including different sodium hydroxide and AGE concentrations, reaction temperatures and times. ¹H‐NMR and FT‐IR were used to analyze the products. AGE‐modified starch, with two degrees of substitution (DS), namely DS = 1.3 and DS = 2.3, was synthesized and used for preparation of a new family of crosslinked composites reinforced with various amounts of bleached softwood fibres. Composite premixes of modified starch, wood fibres and ethylene glycol dimethacrylate (EGDA) were cured in a hot press using 2% (w/w) of benzoyl peroxide at 150°C under high pressure for 10 min. The matrix with high degree of substitution exhibited good processability and was easily processed even for the highest fibre contents, up to 70% (w/w). In addition, scanning electron micrographs showed good dispersion and adhesion between the starch matrix with high degree of substitution and fibre. The original poor mechanical properties of the cured modified starch were markedly improved by the addition of wood fibres. In the extractions tests cured high‐DS and low‐DS composite samples showed weight losses in the range of 1 and 15% (w/w), respectively. No unreacted crosslinker ethylene glycol dimethacrylate was detected in the solutes as determined by NMR.     

Preparation of highly substituted carboxymethyl starch using a twin‐screw extruder

Carboxymethyl starch was prepared by reacting corn starch with sodium mono chloro acetate (SMCA) in a Brabender TSE‐20 co‐rotating twin screw extruder. The effects of the SMCA/starch ratio (theoretical degrees of substitutions 2.73, 3.62, and 4.53), aqueous ethanol/(starch + SMCA) ratio (0.13 and 0.25) and the screw configuration (0, 1, and 2 kneading blocks) on the degree of substitution (DS) and reaction efficiency were studied. A 3 × 2 factorial design with 3 levels of the starch/SMCA ratio and 2 levels of the aqueous ethanol/(starch + SMCA) ratio were used. This 3 × 2 factorial design was blocked, with the screw configuration as the blocking variable. The effects of the SMCA/starch ratio and the screw configuration were found to be significant. The carboxymethylated starches were characterized using FTIR, SEM, and XRD. The microstructure of the carboxymethylated starches, studied using SEM, revealed that the integrity of the starch granules was partially preserved at low aqueous ethanol levels when no kneading block was used. However, for all other reaction conditions either granule agglomeration or fusion was observed. XRD analysis indicated substantial loss of crystallinity in the carboxymethylated starches, irrespective of the damage to the granule structure. The highest DS and the highest reaction efficiency obtained were 1.54 and 0.42, respectively.