Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

This paper describes the synthesis of long‐chain fatty esters of corn starch (starch laurate and starch stearate) with a broad range in degree of substitution (DS = 0.24−2.96). The fatty esters were prepared by reacting the starch with vinyl laurate or vinyl stearate in the presence of basic catalysts (Na₂HPO₄, K₂CO₃, and Na acetate) in DMSO at 110°C. The yellowish products were characterized by ¹H‐, ¹³C‐NMR and FT‐IR. The DS of the products is a function of the carbon number of the fatty acid chain, vinyl ester to starch ratio and the type of catalyst. When performing the reactions using Na₂HPO₄ as the catalyst, the DS for the starch laurate compounds is higher than for the corresponding starch stearates. For low vinyl ester to starch ratios, an increase in the vinyl ester concentration leads to higher product DS values. At higher ratios, the DS decreases, presumably due to a reduction of the polarity of the reaction medium. K₂CO₃ and Na acetate are superior catalysts with respect to activity compared to Na₂HPO₄ and products with DS values close to 3 were obtained.     

非水相中酶法合成糖酯的研究

以固定化脂肪酶作为生物催化剂在非水相反应体系中初步合成了葡萄糖月桂酸酯,探讨了温度、pH、初始水活度、分子筛添加量等影响酯化反应的因素。结果表明最适反应条件:温度45℃、初始水活度0.75、分子筛1g,最高酯化率达65%。     

硬脂酸玉米淀粉酯的合成工艺及性质研究

本文以玉米淀粉为原料,硬脂酸为酯化剂,在微波条件下合成了硬脂酸玉米淀粉酯,着重研究了硬脂酸玉米淀粉酯的性质,如粘度、透明度、抗凝沉性和乳化性。结果表明:经过硬脂酸酯化后的淀粉大大改进了原淀粉的性能,粘度较低、透明度较高、抗凝沉性好并具有一定的乳化性。     

月桂酸玉米淀粉酯的合成工艺研究

以玉米淀粉与月桂酸为原料,脂肪酶为催化剂,干法制备了低取代度的月桂酸玉米淀粉酯。以取代度和特性黏度为评价标准,对影响月桂酸玉米淀粉酯合成的因素:反应时间、反应温度、水分添加量、脂肪酶添加量和月桂酸添加量进行研究。并在此基础上,进行了4因素3水平的正交试验。用DPS软件对正交试验结果进行方差分析,得出了月桂酸玉米淀粉酯合成的最佳工艺条件:以20 g淀粉干基计,月桂酸添加量5%,酶添加量2.5%,水分添加量25%,反应时间3 h,温度60℃。     

月桂酸玉米淀粉酯的合成工艺研究

以玉米淀粉与月桂酸为原料,脂肪酶为催化剂,干法制备了低取代度的月桂酸玉米淀粉酯。以取代度和特性粘度为评价标准,对影响月桂酸玉米淀粉酯合成的因素：反应时间、反应温度、水分添加量、脂肪酶添加量和月桂酸添加量进行研究。在此基础上,通过正交实验得出了合成月桂酸玉米淀粉酯的最佳工艺条件：以20g淀粉干基计,月桂酸添加量5%,酶添加量2.5%,水分添加量25%,反应时间3h,温度60℃。     

酶促合成中长链脂肪酸淀粉酯的性质研究

通过对玉米淀粉经中长链脂肪酸酶促酯化改性后的理化性质的分析,考察其性质的变化,阐明其潜在应用价值,为其实际应用提供理论依据。中长链脂肪酸的引入不仅提高了淀粉乳的黏度、凝沉稳定性和冻融稳定性,且获得了良好的乳化性(67%~98%),且乳化效果明显好于明胶(40%)和蔗糖酯(50%),但与单甘脂(75%)相似。与辛烯基琥珀酸淀粉酯和醋酸淀粉酯相比,低取代度中长链脂肪酸淀粉酯的乳化性(92.36%~97.89%)和冻融稳定性(析水率为17%~20%)要优于辛烯基琥珀酸淀粉酯(析水率为47.2%)和醋酸淀粉酯(析水率为68.63%)。因此,酶促合成的中长链脂肪酸淀粉酯可以作为一种新型的、更为安全的乳化剂和冻融稳定剂广泛的应用到食品、医药及化妆品等领域。     

Effect of Octenylsuccinylation on Rheological Properties of Corn Starch Pastes

Rheological properties of corn starch octenylsuccinate (OSA starch) pastes (5%, w/w), at different 1‐octenylsuccinic anhydride (OSA) contents (0, 1.0, 1.5, 2.0 and 2.5%, w/w) were evaluated in steady and dynamic shear. The OSA starch pastes had high shear‐thinning behaviors and their flow behaviors were described by power law, Casson, and Herschel‐Bulkley models. Magnitudes of consistency index (K, K_h) and yield stress (σ_oc, σ_h) increased with the increase in OSA content and the decrease in temperature. Over the temperature range of 10–50°C, the effect of temperature on apparent viscosity (η_a,100) was described by the Arrhenius equation. The activation energy values (E_a = 10.7–13.9 kJ/mol) of OSA starches were lower than that (E_a = 15.9 kJ/mol) of native starch. Dynamic frequency sweep test showed that both storage modulus (G′) and loss modulus (G′′) of OSA starch pastes increased with the increase in OSA content. Dynamic (η^*) and steady shear (η_a) viscosities of OSA starch pastes at various OSA contents did not follow the Cox‐Merz superposition rule.     

挤压法制备的硬脂酸玉米淀粉酯的性质研究

以玉米淀粉为原料,硬脂酸为酯化剂,用双螺杆挤压机作反应器制备了硬脂酸玉米淀粉酯.对硬脂酸玉米淀粉酯的黏度、稳定性、溶解度、糊化度、乳化特性和消化性等性质进行了测定和分析.     

Empirical Modeling of Starch Ester Synthesis from Octenylsuccinic Anhydride

In the present work, response surface methodology (RSM) was used to determine the mathematical relationship between octenylsuccinic anhydride (OSA) treated maize starch and the octenylsuccinylation reaction conditions. A second‐order polynomial model was chosen to approximate the relationship between the response variable (y, as the degree of substitution “DS” used to define the extent of the octenylsuccinylation) and the three regressors, x₁ as the temperature, x₂ as the time and x₃ as the pH. Analysis of variance (ANOVA) showed a high R² coefficient of 0.9905, thus ensuring a satisfactory adjustment of the selected model with the experimental data. Only temperature‐pH interaction was found to have a non‐significant effect. The positive sign for the regression coefficient of the temperature variable indicated that the y_DS increased with the increased levels of this factor from 25 to 45°C. The negative sign for the coefficient of time and also pH indicated that y_DS decreased as either the time or pH increased in the region of the tested range. The negative coefficients of the interaction between x₂ and x₃ indicated that a simultaneous increase in reaction time with decrease in pH of the esterification reaction led to an increase in y_DS. Maize starch octenylsuccinate synthesis on basis of its DS value was optimized for the three independent variables tested in this study. The predicted value for the DS was 0.02 where temperature, time and pH of the reaction were 28.0°C, 8.1 h, and pH 7.11, respectively. Results of some of the selected physicochemical properties of starch, tested in the present work were also discussed.     

小麦淀粉凝胶质构特性研究

为了掌握不同小麦品种淀粉凝胶质构特性;陕西关中小麦品种和西澳面条用小麦品种的淀粉凝胶质构的异同;淀粉的直链淀粉含量、色度及粘度特性与淀粉凝胶质构特性的关系。以参加陕西省关中小麦品种区域试验的15个小麦品种(品系)、西澳8个面条用小麦品种(品系)为材料,研究了小麦品种淀粉凝胶质构特性及淀粉特性与凝胶质构特性的关系。结果表明:不同小麦品种淀粉凝胶质构特性不同,陕西关中小麦品种之间淀粉凝胶质构特性比西澳面条小麦品种之间差异大。直链淀粉含量与凝胶特性无明显关系;色度中L值与凝胶硬度呈显著正相关;粘度特性与淀粉凝胶质构特性显著相关。关中小麦品种小偃6号、小偃128、秦农068和西澳面条小麦品种具有相似的凝胶质构特性。     

非水相酶法催化长链脂肪酸淀粉酯反应研究进展

长链脂肪酸淀粉酯作为改性淀粉的一种重要类型具有广泛的应用前景。酶作为生物催化剂在非水相中可对淀粉和长链脂肪酸进行酯化,该反应具有底物选择性高、产物专一性强、条件温和、产物可生物降解等优点。本文从酶催化合成反应的机理、酶法催化长链脂肪酸淀粉酯的制备方法、取代度的测定方面进行综述。     

离子液体介质中无催化剂法制备硬脂酸玉米淀粉酯的结构与性能

以玉米淀粉(CS)为原料,离子液体氯化1-烯丙基-3-甲基咪唑(AMIMCl)为反应介质,硬脂酸甲酯(MS)为酯化试剂,无催化剂制备硬脂酸玉米淀粉酯(CSS)。利用红外光谱(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)、热重-红外联用(TGA-FTIR)和哈克流变仪对CSS的结构、热特性及流变特性进行分析。通过单因素及正交实验确定制备CSS最佳工艺条件为：温度90 ℃,时间2.5 h,MS与淀粉(以脱水葡萄糖单元AGU计)摩尔比可根据所需产品的取代度在0.5～3.0范围内选取。结构分析表明,CS已成功与MS发生了酯交换反应,反应按SN2亲核取代机理进行;所制备的CSS失去了CS的结晶与颗粒结构。热特性分析表明,在氮气氛围下CSS所接入的硬脂酸基团能稳定至220 ℃。流变特性分析表明,CSS糊液为符合幕律定律的假塑性流体,具有触变性。     

淀粉-玉米醇溶蛋白可食性膜的筛选与性能研究

以玉米淀粉和玉米醇溶蛋白作为基础原料,研究可食性膜的成膜条件和膜性能。玉米淀粉液经糊化、掺入脱色的玉米醇溶蛋白、添加甘油增塑剂、匀浆、脱泡、成膜后,检测膜的抗拉强度、断裂伸展率、溶解度、透明度、微观表面特征。配制质量分数为4%、5%、6%、7%的玉米淀粉液分别制膜,检测并筛选一适宜浓度,同时筛选制备脱色玉米醇溶蛋白液。玉米淀粉糊化后,分别按其体积的0%、10%、15%、20%、25%、30%掺入脱色玉米醇溶蛋白液,制膜,筛选适宜掺入比例。测试筛选添加质量分数为1.0%、1.2%、1.4%、1.6%的甘油增塑剂的成膜效果。结果显示,添加玉米醇溶蛋白液能够提高抗拉强度和断裂伸展率,降低透明度和溶解度,但添加10%有反抗拉强度现象。筛选确定淀粉质量分数5%,按体积分数15%掺入含玉米醇溶蛋白0.5%的脱色液,添加1.2%的甘油增塑剂,获得的可食性淀粉-玉米醇溶蛋白膜具有良好的机械性能和表观特征。     

Effect of Reaction Conditions and Alkyl Chain Lengths on the Properties of Hydroxyalkyl Starch Ethers

Starch applications in the plastics industry have been investigated intensively for many years. Unfortunately, native starch is unsuitable for most applications in polymers, because of its hydrophilic and brittle character. Modification of native starch can be a solution of this problem. In our research programme we developed an environmentally friendly process for the preparation of starch derivatives with long hydrophobic side chains based on natural products derived from vegetable fats and oils on the one hand and amylomaize starch on the other hand. In this process modification is carried out by the addition of longchain 1,2‐epoxyalkanes (chain lengths varying between 6—18 C atoms) to starch in an alkaline aqueous medium. Reaction yields and molar degrees of substitution depended on chain length, reaction time, temperature and catalyst concentration. Under optimised reaction conditions molar degrees of substitution of hydroxyalkyl starch ethers for theoretical molar substitution (MS) = 3.0 decreased from MS=1.8 (C₆ starch ether) to MS=0.2 (C₁₈ starch ether), respectively. Hydrophobic properties of starch products were measured in order to reveal structural effects obtained at different reaction conditions. Water solubility and water absorption properties of hydroxyalkyl starch ethers decreased with increasing chain length and number of hydroxyalkyl substituents. Thermal and thermoplastic properties of starch ethers were investigated in order to determine their potential use as biodegradable polymers in the plastics industry. As expected, thermoplasticity of starch ethers increased with increasing MS and increasing chain length of the hydroxyalkyl side groups.     

EPR Studies of Thermally Treated Oxidized Corn Starch

The formation of radicals in oxidized corn starch at 20–250°C in air was investigated by quantitative EPR spectroscopy. It was found that the presence of carboxyl groups in the oxidized starch increases the starch's ability to generate radical species. Introducing Cu²⁺ ions into the starch, as a catalyst or as an EPR probe, leads to the formation of copper‐carboxyl complexes containing two carboxyl ligands. Drastic increase in the number of radical species at about 250°C is accompanied by a decrease in the intensity of EPR signal of Cu²⁺‐carboxyl complexes, indicating that the thermal degradation of oxidized corn starch occurs with the formation of radicals, probably via breaking the chemical bonds in the carboxyl groups.     

玉米抗性淀粉的制备及其性质的研究

对玉米抗性淀粉的制备工艺进行了研究,确定了最佳的制备工艺:淀粉调乳(浓度2 5 % ,pH值8 0 )→预糊化→压热处理(12 0℃,30min)→冷却→低温静置(4℃,2 4h)→提纯。按该工艺制备RS ,其产率可达10 4 7%。研究了玉米抗性淀粉的性质,包括抗酶解能力、对普通淀粉黏度特性的影响、吸水能力及微观颗粒形貌。     

玉米淀粉与玉米变性淀粉性质比较研究

测定了玉米淀粉、羟丙基淀粉、羧甲基淀粉、淀粉磷酸酯的冻融稳定性、透光率、膨胀度、粘度、糊化特性等主要物理性质并进行了比较。试验结果表明：变性淀粉与玉米淀粉的性质不同，由于变性淀粉引进了羟丙基、羧甲基、磷酸基团等亲水性基团，使淀粉极性增强，亲水能力增大，使其都具有较强的冻融稳定性、抗凝沉性，较高的膨胀度、透明度，因此变性淀粉具有更广阔的应用性。     

机械活化玉米淀粉的辛烯基琥珀酸酐酯化改性

采用行星式球磨机对玉米淀粉进行机械活化,再与辛烯基琥珀酸酐（octenyl succinic anhydride,OSA）发生酯化反应制备OSA淀粉酯。研究机械活化时间、反应温度、反应体系pH值、淀粉乳质量分数、反应时间因素对玉米淀粉酯化反应的影响,并采用二次回归正交旋转组合设计方法和响应面分析对制备条件进行优化。结果表明,机械活化对玉米淀粉OSA酯化反应有明显的增强作用,且反应不受pH值的影响;得到最优工艺条件为机械活化10 h、反应温度33.1 ℃、pH 8.45、淀粉乳质量分数12.2%、反应时间3 h,在此条件下制得机械活化辛烯基琥珀酸淀粉酯的平均取代度为0.020 3。