高取代度淀粉醋酸酯合成工艺优化及结构表征

以玉米淀粉为实验材料,在催化剂用量、醋酸与醋酸酐体积比、反应时间、反应温度4个单因素试验基础上,利用响应面试验设计法进行试验设计,获得取代度与各单因素的函数关系,并建立高取代度淀粉醋酸酯合成工艺模型。通过回归方程和响应曲面,得到淀粉醋酸酯最佳合成工艺为催化剂用量0.11mL、醋酸与醋酸酐体积比1:1.39、反应时间1.59h、反应温度87.61℃。验证实验结果显示,在此条件下淀粉醋酸酯取代度为2.95。傅里叶红外光谱分析表明,淀粉醋酸酯葡萄糖单元上的羟基逐渐发生酯化,而且随着取代度测定值升高,乙酰基含量增大。扫描电镜照片显示,淀粉醋酸酯表面变得更为粗糙,孔隙增多且呈蜂窝状,说明酯化反应不仅发生在淀粉颗粒表面,同时也发生在淀粉颗粒内部。     

高直链淀粉微波制备高取代度醋酸酯淀粉的研究

以高直链玉米淀粉为原料,醋酸酐为乙酰化试剂.浓硫酸为催化剂,利用微波辐射技术合成高取代度的醋酸酯淀粉.通过正交实验确定了高取代度醋酸酯淀粉的最佳合成工艺为:绝干高直链玉米淀粉20g,醋酸酐70mL.浓硫酸用量0.4mL,辐射时间6min,辐射功率600W,制得取代度为1.4428的醋酸酯淀粉.并对高取代度醋酸酯淀粉的特性粘度和溶解性等性质进行了测定分析.     

取代度对醋酸酯淀粉结构与性能的影响

取代度的大小对醋酸酯淀粉的性能有重要的影响。利用相同的制备工艺获取3种不同取代度的醋酸酯淀粉,采用红外光谱仪对淀粉的分子构成做出表征分析,在扫描电镜(SEM)下观察不同取代度醋酸酯淀粉颗粒的表面及内部的微观结构与原淀粉进行对比分析,并对浆液的凝沉性及淀粉的成膜性进行测试。结果表明,取代度较低的醋酸酯淀粉颗粒表面发生的变化较小,浆液的凝沉性及成膜性与原淀粉相差不大,浆膜较脆硬;高取代度的醋酸酯淀粉中酯基含量较明显,淀粉颗粒的网状结构突出,浆膜的吸湿率较低,保湿性较差。     

醋酸酯化芋艿改性淀粉的制备及其性质研究

本文以芋艿淀粉为原料,选取醋酸为酯化剂制备醋酸酯化改性淀粉,考察反应温度、反应p H、醋酐用量及反应时间对醋酸酯改性淀粉中乙酰基质量百分比的影响,通过正交实验设计确定醋酸酯法芋艿改性淀粉的最优工艺,并对原淀粉和醋酸酯化淀粉进行性质比较分析。结果表明:反应温度、p H、反应时间对乙酰基质量分数有极显著的影响(p0.01),醋酸酐用量(0.16~0.37m L)对乙酰基质量分数的影响较显著(p0.01),醋酸酐用量(0.37~0.51m L)对乙酰基的影响不显著(p0.05);通过正交实验确定最佳制备条件为反应温度25℃、p H8.0、醋酸酐用量0.44m L、反应时间1.5h,在此条件下制备得到的芋艿改性淀粉乙酰基质量分数为3.56%。理化性质的检验结果表明改性淀粉较原淀粉透明度提高41.28%、溶解度增大12.36%,膨胀率提高2.94%。改性淀粉的X-射线衍射图和芋艿淀粉的特征谱线一致,晶型为A型;芋艿淀粉颗粒较完整,没有裂缝,表面较光滑,形貌呈多面体,大颗粒淀粉周围附着许多小颗粒。芋艿改性淀粉颗粒完整,较光滑、多孔,呈多面体。     

3种马铃薯改性淀粉的理化性质及结构分析

以马铃薯淀粉为材料,制备氧化淀粉、醋酸酯淀粉、氧化醋酸酯淀粉,比较其理化性质,并通过红外光谱(FT-IR)、电子扫描显微镜(SEM)等对其结构进行分析。结果表明:氧化淀粉、醋酸酯淀粉、氧化醋酸酯淀粉比原淀粉透明度高、流动性好、附着力强、涂抹性好。FT-IR实验表明氧化淀粉有羧基的特征吸收峰,而氧化醋酸酯淀粉酯化改性过程中有醋酸酯基团的生成。SEM扫描实验显示氧化淀粉的外形比较规整多为球状或椭球状,表面较光滑;醋酸酯淀粉颗粒形状未发生大的改变,但规整度很差;氧化醋酸酯淀粉颗粒完整,表面粗糙,低取代度的酯化反应仅发生在淀粉颗粒表面。     

机械活化木薯淀粉制备低取代度醋酸酯淀粉的研究

以机械活化0.5h的木薯淀粉和木薯原淀粉为原料,以醋酸酐为酯化试剂,氢氧化钠为催化剂,制备低取代度木薯淀粉醋酸酯。以淀粉醋酸酯的取代度和反应效率为评价指标,分别研究反应温度、反应时间、醋酸酐用量、pH各因素对其取代度和反应效率的影响。实验结果表明,反应温度、反应时间、醋酸酐用量、pH对木薯淀粉醋酸酯的取代度和反应效率均有影响。机械活化能显著提高木薯淀粉醋酸酯化反应的取代度和反应效率。通过试验得到制备低取代度木薯淀粉醋酸酯的较佳工艺条件为:反应温度为30℃,反应时间为40min,醋酸酐用量为0.15mL,pH为8.5时,在此条件下制备的醋酸酯淀粉的取代度为0.075、反应效率为87.45%。并用红外光谱对醋酸酯淀粉进行分析。     

机械活化固相化学反应制备木薯醋酸酯淀粉

为获得制备醋酸酯淀粉的新工艺,采用机械活化固相化学反应法制备木薯醋酸酯淀粉。以醋酸酯淀粉的取代度为评价指标,分别探讨醋酸酐用量、NaOH用量、球磨温度、球磨时间、搅拌速度、球磨介质的堆体积等因素对木薯淀粉醋酸酯反应的影响,并对影响因素进行了正交优化。结果表明:在醋酸酐质量分数60%、NaOH质量分数2.0%、球磨温度60℃、球磨时间60 min、搅拌速度380 r/min、球磨介质堆体积500 mL的反应条件下,制备得到的木薯醋酸酯淀粉的取代度为0.263 2,反应效率为25.57%。并采用红外光谱(FTIR)、X-射线衍射(XRD)对木薯醋酸酯淀粉的结构进行了表征。机械活化对淀粉发生酯反应有显著的强化作用。     

响应面法优化高取代度黄姜醋酸酯淀粉的制备

以浓硫酸作催化剂,黄姜淀粉为原料,冰醋酸和醋酸酐为改性剂,合成了高取代度的黄姜淀粉醋酸酯。运用响应面法优化了制备工艺,结果表明制备黄姜醋酸酯淀粉的最佳反应条件为反应温度70℃,反应时间2.5h,0.20mL H2SO4作催化剂,醋酸酐与醋酸体积比为32∶68,取代度为1.70     

不同压力预处理对小麦醋酸酯淀粉制备的影响及产物结构表征

为探究不同预处理压力对淀粉酯化反应的影响效果,将小麦淀粉乳(40%)分别在0、20、40、60和80 MPa下处理后以醋酸酐进行酯化反应。通过傅里叶变换红外光谱仪(FTIR),偏光显微镜(PLM),X射线衍射(XRD)和扫描电镜(SEM)对小麦醋酸酯淀粉进行形貌和结构分析。结果表明:经过醋酸酐作用后,淀粉分子中引入酯羰基。高压均质预处理使小麦淀粉酯化程度显著提高,与未均质处理相比,取代度增幅达47.70%。醋酸酯淀粉在40 MPa下取得最大取代度0.096。偏光十字图显示随着压力增大,淀粉颗粒脐点处发生爆裂且裂缝沿脐点向外扩大。当均质压力达到80 MPa时,部分淀粉颗粒的双折射现象几乎消失。高压均质和低酯化反应都未改变小麦淀粉的A晶型,但压力迫使淀粉颗粒结晶结构破坏。醋酸酯淀粉保持了原小麦淀粉颗粒形貌,但在20 MPa下的淀粉颗粒出现剪切微变形和机械折叠。在80 MPa下,淀粉颗粒表面出现严重的机械损伤和断裂,一些大颗粒淀粉瓦解且相互之间有粘连,是取代度降低的原因之一。     

不同原料微波辐射制备醋酸酯淀粉及性质的研究

分别以马铃薯、小麦、玉米淀粉为原料,以醋酸酐为乙酰化试剂,利用微波辐射技术时醋酸酯淀粉的合成工艺和性能进行了研究.结果表明,由不同原料合成的醋酸酯淀粉取代度不同,其中马铃薯淀粉合成的醋酸酯淀粉取代度最高,小麦最低.并且对三种醋酸酯淀粉的凝沉性和透明度进行了测定分析.     

Study on the morphology,crystalline structure,and thermal properties of Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution

Fritillaria ussuriensis Maxim. starch acetates with different degrees of substitution (DSs) were prepared by reacting native starch with glacial acetic acid/acetic anhydride using sulfuric acid as catalyst. XRD of acetylated starch revealed that there was loss of crystallinity with increasing DS. The carbonyl group signal at 1750 cm⁻¹ appeared in the FTIR spectra. The intensity of this peak increased whereas the intensity of the hydroxyl groups at 3000–3600 cm⁻¹ decreased. The thermal behavior of the samples was investigated and the results showed that the acetylation decreased the gelatinization temperatures and ΔH_gel, and thermal stability of high DS acetylated starch (DS = 2.82) was much better than that of the original starch and partially substitute starch acetate (DS = 1.52). The SEM suggested that most of the starch granules were disintegrated into many visible fragments along with the increasing of DS. The starch acetate with different DS prepared in this paper has many potential uses in food and pharmaceutical applications for its lower gelatinization temperature and thermal stability properties.     

不同酰基改性淀粉结构及热稳定性研究

本文用不同链长酸酐对G50玉米淀粉进行化学改性获得酯化淀粉。利用扫描电子显微镜、傅里叶红外光谱、X-射线衍射仪、小角X-射线散射仪及热失重分析仪表征酯化淀粉的表面形貌、分子结构、结晶结构、有序微区结构以及热性能。结果表明,酸酐碳链越长,取代反应程度越低;酯化淀粉颗粒呈碎片状,丁酸酯淀粉(DS=1.38)和己酸酯淀粉(DS=1.37)易聚集成团;酯化淀粉整体呈现无定型态,高取代度乙酸酯淀粉内部有序微区破坏程度最大,取代度相近时,酸酐碳链越长,对应的酯化淀粉存在周期性长程有序结构;相比于原淀粉,酯化淀粉的热稳定性得到增强,且当酸酐添加量相同时,随着酸酐碳链的增加,酯化淀粉的热稳定性增强程度呈下降趋势。以上结果可为完善酯化淀粉应用提供参考。     

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。     

Homogeneous synthesis and characterization of starch acetates in ionic liquid without catalysts

Homogeneous modification of corn starch with acetic anhydride was performed in ionic liquids 1‐butyl‐3‐methylimidazolium chloride (BMIMCl) without catalysts. The results indicated that the pretreatment of starch, which starch was dissolved in BMIMCl at 105°C for 2 h before reaction, provided feasible reaction environment for starch functionalization. Optimum modification conditions for maximum degree of substitute (DS 2.11) were shown as following: acetic anhydride/anhydroglucose units (AGU) molar ratio 5:1, reaction temperature 105°C and reaction time 2 h. The pretence of acetyl groups in starch products was confirmed by FTIR and ¹H NMR spectroscopy. SEM and XRD data showed that the crystalline structure of native starch was disrupted and new structure was formed during the dissolution and modification processes. The higher DS due to acetylation had a beneficial effect on the thermal stability of samples.     

乙酰化柠檬酸酯化交联机械活化淀粉的制备及性质分析

以机械活化木薯淀粉为原料,醋酸酐为酯化剂,柠檬酸为交联剂,采用溶剂法制备乙酰化柠檬酸酯化交联淀粉,考察了机械活化时间、混合酸添加量、反应温度、反应时间、柠檬酸与乙酸酐质量比等因素对乙酰化柠檬酸酯化交联淀粉沉降积的影响,并对制备得到的酯化交联淀粉进行结构表征及性质测定.结果表明,制备最佳工艺条件为:机械活化时间40 mi...     

二氢杨梅素乙酸酯的合成及抗氧化作用

目的:将二氢杨梅素进行酯化改性,考察二氢杨梅素酯化衍生物结构与抗氧活性间的内在关系.方法:采用改变乙酸酐与二氢杨梅素投料比,合成不同酯化程度的二氢杨梅素酯,并用猪油体系测定其抗氧活性.结果:用磷酸作催化剂,可有效地合成二氢杨梅素酯,所合成的化合物均有较强的抗氧化能力.结论:通过对二氢杨梅素酯化改性,明显地提高了二氢杨梅素的抗氧化作用能力.     

Physicochemical Properties and Digestion Characteristics of Corn Starch Esterfied by Malic Acid

The objective of this study was to evaluate the effects of different degree of substitution on structural characteristics and crystalline properties of resistant starch esterfied by L‐malic acid. With the deepening of the esterification reaction, malate starches particles became larger, particle surface cracks and grooves increased which led to a decline in whiteness of malate starches. With the increase in the degree of substitution (DS), the initial phase transition temperatures (To) and endothermic enthalpies (ΔH) of malate starch gradually decreased. The XRD results indicated that with the increase of DS, the diffraction peak at 15.1° disappeared in the spectrum. When the DS of malate starches reached 0.116, the content of resistant starch (RS) accounted for the majority of the total starch.     

甘薯淀粉辛烯基琥珀酸酯物化性质的研究

以甘薯淀粉为参照,采用扫描电镜分析、红外光谱、差示扫描量热分析、快速粘度分析等现代仪器分析方法对甘薯淀粉辛烯基琥珀酸酯的颗粒形貌、结构特征、热力学特性、黏度特性等物化性质进行了测定和研究。结果表明,甘薯淀粉经辛烯基琥珀酸酐酯化后,其颗粒表面出现不同程度的凹陷和破裂,说明酯化反应发生在淀粉颗粒表面;产品的红外光谱在1718 cm-1和1554 cm-1处出现新的吸收峰,其中1718 cm-1处的吸收峰表明酯羰基的存在,说明分子中引入了新的官能团,1554 cm-1处出现的特征峰是缘于RCOO-不对称的伸缩振动;产品的起始糊化温度、峰值糊化温度、糊化结束温度和糊化热焓值降低,说明淀粉结晶结构的致密程度下降;随着产品取代度的增加,淀粉糊峰值粘度升高,出峰时间提前,糊化温度降低。     

羟丙基戊二酸酯复合改性木薯淀粉的性质分析

以木薯淀粉为原料,利用乙醇溶剂法先进行羟丙基醚化改性,再采用戊二酸酐作酯化剂进行处理而制得复合改性淀粉。采用傅里叶变换红外谱仪（FT-IR）、扫描电镜（SEM）和DV-I Prime旋转粘度仪等对样品的微观结构进行表征及其性能分析。红外分析表明改性淀粉在1287 cm-1处出现羟丙基的吸收峰,羟丙基戊二酸复合改性淀粉在1733 cm-1处和1555 cm-1处出现新的酯化吸收峰,说明原淀粉已接入了羟丙基和戊二酸基团。复合变性前后淀粉的表观形貌变化,证实了反应不仅发生在淀粉颗粒表面,也发生在淀粉颗粒内部。旋转粘度仪分析则表明了复合改性后的羟丙基戊二酸酯淀粉的粘度和抗流变性有很大的提升,当DS为0.0362时,淀粉糊的粘度为12100 mPa?s,比羟丙基木薯的粘度提高了6.72倍（羟丙基木薯淀粉的粘度为1800 mPa?s）。     

Preparation and Properties of Octenyl Succinic Anhydride Modified Early Indica Rice Starch

Octenyl succinic anhydride (OSA) modified early indica rice starch was prepared in aqueous slurry systems and the major factors affecting the esterification were investigated systematically. The physicochemical properties of the products were determined by means of Fourier transform infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction and Rapid Visco Analyser (RVA). The results indicated that the suitable parameters for the preparation of OSA starch from early indica rice starch in aqueous slurry systems were as follows: concentration of starch slurry 35% (in proportion to water, w/w), reaction period 4 h, pH of reaction system 8.5, reaction temperature 35°C, amount of OSA 3% (in proportion to starch, w/w). The degree of substitution (DS) was 0 018 and the reaction efficiency (RE) was 78%. FT‐IR spectroscopy showed characteristic absorption of the ester carbonyl groups in the OSA starch at 1724 cm^‐1. SEM and X‐ray diffraction revealed that OSA groups acted by first attacking the surface and some pores formed, but OSA modification caused no change in the crystalline pattern of rice starch up to DS 0.046. RVA results indicated that the starch derivatives gelatinized at shorter time to achieve higher viscosities with increased OSA modification.