芭蕉芋直链和支链淀粉纯品的提取及其光谱分析

分离提纯芭蕉芋淀粉中的直、支链淀粉,表征其纯度,建立快速测定芭蕉芋淀粉中直链淀粉含量的双波长法。正丁醇结晶法分离纯化直、支链淀粉;光吸收特性分析法表征直、支链淀粉纯度;根据双波长法原理,在测定波长617nm,参比波长504nm处测定芭蕉芋淀粉中直链淀粉含量。分离提纯得到的直、支链淀粉最大吸收波长分别为630～645nm和548～554nm,蓝值分别为1.167±0.209和0.122±0.001,均处于相应分布范围,表明提纯后直、支链淀粉的纯度较高;直链淀粉在0～80mg/L浓度范围内与吸光度呈线性关系,r=0.9998。正丁醇结晶法能有效地分离纯化芭蕉芋直、支链淀粉;光吸收特性分析法可有效地表征直、支链淀粉纯度;双波长法操作简便、准确,无需分离即可快速测定芭蕉芋淀粉中直链淀粉含量。     

葛根淀粉提取及直链、支链淀粉的双波长测定

以淀粉提取率为指标,采用正交实验研究了葛根淀粉的加工工艺,并确定了最佳工艺参数为:料水比为2:17,浸泡液的pH为8.5,浸泡时间为1h;同时采用双波长分光光度法对葛根中直链淀粉和支链淀粉的显色反应和光度测定的最佳条件进行了详细的考察,根据吸收光谱,确定直链淀粉的测定波长为617nm和476nm,支链淀粉的测定波长为415nm和532nm,建立回归方程并求得葛根淀粉中直链淀粉的含量为18.29%,支链淀粉的含量为77.24%。      

马铃薯中直链淀粉和支链淀粉含量测定方法的优化

本文以马铃薯为原料,优化马铃薯淀粉预处理方法,改善直链淀粉和支链淀粉的测定波长,完善淀粉的测定方法。采用直链淀粉和支链淀粉标准品绘制标准曲线,以未经过脱糖脱脂、脱脂、脱糖、先脱糖后脱脂、先脱脂后脱糖为样品预处理方法,分析不同预处理方法对直链淀粉和支链淀粉含量的影响。结果表明,直链淀粉和支链淀粉的最大吸收波长分别为609 nm和546 nm,参比波长分别为473 nm和734 nm。标准方程回归系数均大于0.999。先脱脂后脱糖样品颗粒溶解性好,支链淀粉含量为70.27%,直链淀粉含量为12.38%。因此,采用先脱脂后脱糖处理样品,在双波长法条件下可以准确测定马铃薯中直链淀粉和支链淀粉含量。      

近红外光谱应用于高粱中总淀粉、直链淀粉与支链淀粉的定量分析

酱香型白酒以高粱为主要原料发酵而成,高粱中的淀粉,尤其是支链淀粉的含量对于酱香型白酒的产品质量起着至关重要的作用,因此针对其总淀粉、直链淀粉与支链淀粉的检测手段研究也应受到人们高度的重视。傅里叶变换近红外光谱法因其准确性高、稳定性好以及快速无损检测等特点,在建立总淀粉、直链淀粉和支链淀粉同时定量分析模型方面得到了较为成功的应用。结果表明,总淀粉、直链淀粉以及支链淀粉的定量分析模型相关系数分别达到0.954 9、0.923 6和0.940 1,交互验证均方根误差分别为1.027 1、0.088 5和1.264 6。可见,基于近红外光谱技术的定量分析方法可适用于高粱中总淀粉、直链淀粉与支链淀粉的同时定量分析。     

双波长分光光度法测定新鲜怀山药中直链与支链淀粉的含量

以新鲜怀山药为原料制备山药粉,通过石灰水浸泡工艺提取山药淀粉。以碘为显色剂,扫描直链淀粉和支链淀粉与碘形成复合物的全波长吸收光谱。利用不同浓度的直链与支链淀粉标准品分别与碘形成复合物从而得到淀粉含量与吸光度差值之间的线性关系制作出标准曲线,根据标准曲线计算出样品中直链淀粉与支链淀粉的含量。根据双波长选择原理和扫描光图谱,确定直链淀粉的测定波长为 600nm,参比波长为 532nm; 支链淀粉的测定波长为560nm,参比波长 659nm。实验说明直链淀粉与支链淀粉的测定相对标准偏差分别为 0.27% 与 0.63% 、回收率也分别达到了96.18%与97.89%,检出限分别为0.09mg/L 与 1.58mg/L,再经准确性分析验证了用双波长法测定山药淀粉中直链淀粉与支链淀粉的含量的检测方法具有较为准确的效果。      

双波长法测定绿豆中的直链和支链淀粉

建立绿豆中直链淀粉和支链淀粉含量同时测定的双波长分光光度法,研究光度测定的影响因素,并对方法精密度和加标回收率进行考察。直链淀粉的测定波长和参比波长分别为610nm和498nm,支链淀粉为553nm和709nm。方法精密度良好,直链和支链淀粉平均回收率分别为94.10%和90.94%。建立回归方程并求得3种绿豆的直链淀粉含量为11.70%~12.67%,支链淀粉含量为32.70%~34.22%。     

Effect of retrogradation,pancreatin digestion and amylose/amylopectin ratio on the fermentation of starch by Clostridium butyricum (NCIMB 7423)

Using three different maize starches (maize, waxy maize and high amylose maize, containing 25%, 1% and 52% amylose, respectively) the influence of amylose/amylopectin content and of retrogradation on fermentation by the porcine caecal anaerobe Clostridium butyricum was assessed. Small intestine digestion was simulated using pancreatin before the starches were exposed to bacterial fermentation. It was found that retrogradation appeared to alter the extent of the fermentation and hence the amount of short-chain fatty acids produced, while pancreatin digestion appeared to alter the way in which the organism fermented the starch and hence the acetate/butyrate ratio. The amylose/amylopectin ratio seemed to have more influence on the way the starch was fermented by the bacteria after the starch had been subjected to digestion with pancreatic enzymes, but had less influence when the starch had been retrograded. © 1998 SCI.     

Retrogradation of sweet potato amylose and amylopectin with narrow molecular weight distribution

Retrogradation of sweet potato amylose and amylopectin with narrow molecular weight distribution at different temperatures was investigated by X-ray diffraction (XRD). Atomic force microscope (AFM), scanning electron microscope (SEM) and light microscopy were combined to study the morphology of the molecular assemblies during retrogradation. Avrami equation was used to the retrogradation kinetics the of above starches by determining the crystallinity and the ratio of peak area of two distinctive peaks. It was found that only the ratio of peak area/total area at 2θ = ~16.3° could represent the crystallinity of retrograded starch-containing amorphous regions. Considering the crystallinity as retrogradation rate, only the retrogradation kinetics of sweet potato amylose could be analysed by Avrami equation, but not the amylopectin’s. All Avrami exponents n of amyloses at any temperatures were less than 1.0, indicating instantaneous nucleation and rod-like growth. AFM results showed that the maximum heights of layered structure for sweet potato amylose, amylopectin and blending of both were approximately 4800, 180 and 200 nm, respectively. The height of the former two decreased during storage, but the height of blending remained unchanged. Amylose served as nuclei of amylopectin during starch retrogradation.     

淀粉颗粒结构体系

该文就淀粉分子、微晶和淀粉颗粒结构组成及其相互间关系进行论述。由支链淀粉分子形成无定形层和结晶层构成微晶,当低分支或链长较短分子存在于微晶时会形成缺陷微晶,常态微晶组成淀粉颗粒中硬质骨架,而缺陷微晶组成软质骨架,微晶还原端朝向颗粒脐点;依据常态微晶和缺陷微晶排列,淀粉颗粒分为同型骨架和异型骨架两种类型。     

盐对不同直链含量玉米淀粉理化特性及流变学特性的影响

分析了盐对不同直链含量玉米淀粉的理化特性及流变学特性的影响。结果表明,盐抑制了淀粉颗粒的膨胀,盐浓度越大,抑制作用越强。盐质量浓度为0 g/100 mL的蜡质淀粉和普通淀粉膨胀势在65℃到75℃迅速增加,2.0 g/100 mL时膨胀势在75℃到85℃迅速增加且幅度最小。蜡质淀粉和普通淀粉DSC图谱呈G峰和M2峰,高直链淀粉呈G峰。盐提高了凝胶化起始温度,蜡质淀粉从50.1℃增加到90.2℃,普通淀粉从56.6℃增加到99.6℃,高直链淀粉从98.8℃增加到105.7℃。盐也抑制了淀粉的糊化进程,盐浓度越大,糊化温度越高。普通淀粉的储存模量G',损耗模量G"和表观黏度η大于蜡质淀粉。普通淀粉和蜡质淀粉在低盐浓度(0.6g/100 mL)下的G'、G"和η值均大于高盐浓度(2.0 g/100 mL)。     

淀粉链/支比对淀粉-壳聚糖交联薄膜结构及性质的影响

本文以4种玉米淀粉(waxy、normal、G50、G80)制备淀粉-壳聚糖交联薄膜,利用扫描电子显微镜(SEM)、红外光谱分析仪(FTIR)、X-射线衍射仪(XRD)、接触角仪(CA)及热重分析仪(TGA)探讨了不同淀粉-壳聚糖交联薄膜的结构和性质差异。结果表明,壳聚糖自交联薄膜的断面易产生孔洞,而淀粉-壳聚糖交联薄膜断面中无孔洞结构;随着直链淀粉含量升高,交联薄膜断面的粗糙形貌更加明显。在交联体系中,壳聚糖与淀粉分子形成新的氢键,G50、G80自交联薄膜在2θ=17.36°附近弱衍射峰消失,4种淀粉-壳聚糖交联薄膜整体均呈无定型态;壳聚糖自交联薄膜的水接触角CA=76.57°±1.35°,不同链/支比淀粉与壳聚糖交联后,淀粉-壳聚糖交联薄膜的接触角均增大,且支链淀粉含量越高,薄膜的亲水性越强;同时,淀粉-壳聚糖交联薄膜的热稳定性低于壳聚糖或淀粉自交联薄膜。以上结果可为淀粉-壳聚糖交联薄膜在食品包装中的合理应用提供参考。     

微乳化法合成羟丙基高直链淀粉研究

系统地研究以玉米高直链淀粉、环氧丙烷为主要原料,采用微乳化法合成羟丙基高直链淀粉工艺,通过实验探讨各影响因素对产品取代度的影响;并用X射线衍射仪、电子扫描仪等对产品性能进行分析。     

支链淀粉含量对玉米淀粉浆料糊化和结晶性能的影响

将支链淀粉加入到玉米淀粉中组成混合纺织浆料,采用RVA和XRD研究了支链淀粉含量对淀粉浆料流变性以及结晶性能的影响。结果表明：随着支链含量的增加,淀粉浆液的峰值粘度、谷值粘度、末值粘度逐渐降低,衰减值和回生值也逐渐变小,达到峰值的时间缩短,加入支链淀粉有利于淀粉糊化和浆液稳定;同时,淀粉膜的结晶度随支链淀粉含量增加而减小,晶体尺寸呈增长趋势。     

Simultaneous estimation of amylose,resistant, and digestible starch in pea flour by visible and near-infrared reflectance spectroscopy

Due to its health benefits, resistant starch (RS) has received increasing attention from the public, and there is a need to develop methods to measure the amylose and RS concentration in pea (Pisum sativum L.) flour. The aim of this study was to develop a visible and near-infrared reflectance (vis–NIR) model for the simultaneous determination of amylose, RS, and digestible starch (DS) in pea flour. A total of 123 dry pea samples consisting of different pea varieties grown in different environments were collected, and ground to flour, and then the vis–NIR spectra were scanned. The amylose, RS, and DS contents of the pea flours were also measured by an enzymatic colorimetric assay. The spectra data were calibrated with the enzymatic colorimetric-assayed values. Results showed that amylose, RS, and DS in the pea flours can be simultaneously estimated using the vis–NIR spectra. Instead of using the full spectrum (300–2300 nm), we found the most efficient wave bands lying in the visible region between 370 and 560 nm and the NIR spectra in the range of 1600–1800 nm. Using the stepwise regression with backward elimination method, the multiple linear regression (MLR) models were developed from the most efficient wavelengths. The MLR models had the determination coefficients R² of 0.95, 0.76, 0.80, and 0.88 for amylose, RS, DS, and total starch, respectively. The correlation coefficients between model estimated and the enzymatic colorimetric assayed values were 0.97, 0.80, 0.85, and 0.93 for amylose, RS, DS, and total starch, respectively.     

Combining high‐amylose and waxy starch mutations in barley

Inbred lines, from a cross between barleys carrying the waxy and high‐amylose genes respectively, were characterised by the presence of both, either or neither of the genes and grown under field conditions. Starch granule proteins were separated by SDS‐PAGE and lines carrying the waxy gene, with or without the high‐amylose gene, had greatly reduced intensities of the 60 kDa band associated with granule‐bound starch synthase. One representative sample of each starch type was also grown under two controlled environment (CE) regimes. Starch properties were assessed on field‐ and CE‐grown samples of these genotypes and large differences were observed among starch types. Growth conditions generally had comparatively little effect on the starch properties measured. The waxy and high‐amylose genes appeared to have additive effects, both in reducing modal granule size and in increasing gelatinisation temperature significantly above that observed when only one of the genes was present. The genotype with both mutations produced a starch with phosphorus content and blue value, after removal of lipid, slightly higher than those of the waxy type and with an RVA profile similar to that of the wild type, but with lower peak and final viscosities. © 2001 Society of Chemical Industry     

微波对高链玉米淀粉颗粒性质影响的研究

微波是一种能以高频的方式使物质在电磁场中加热的非电离能量。本文研究了淀粉经微波作用后性质的变化,结果表明,微波作用后淀粉的颗粒形貌没有发生变化,偏光十字存在,部分颗粒脐点表面出现小孔,X-射线主要衍射峰的强度增大,晶型由B型转为A型。     

直链淀粉晶种对淀粉回生的影响机制

由于淀粉回生影响因素复杂和研究手段局限,基于直链淀粉主导的短期回生阶段和支链淀粉主导的长期回生阶段关联性的回生共性机制未得到系统阐述。基于此,该研究制备短期回生的直链淀粉晶种,采用FTIR、¹³C CP/MAS NMR等手段,研究其诱导大米淀粉的长期回生过程与规律,揭示短期回生与长期回生关联性。结果表明,所制备的直链淀粉晶种粒度分布在200～450 nm,添加晶种导致淀粉短程有序度由0. 670最高提高至0. 887,双螺旋含量由14. 86%最高提高到了22. 80%。回生淀粉的短程有序度、双螺旋含量显著提高,表明所制备直链淀粉晶种显著促进淀粉长期回生过程,这种晶体协同增长效应,丰富了淀粉回生共性机制。     

不同直链淀粉含量的稻米淀粉黏滞特性研究

用快速黏度分析仪分析了不同直链淀粉含量的稻米淀粉黏滞特性,结果表明不同品种具有不同特征性RVA谱。消减值和直链淀粉含量达极显著正相关,相关系数为0.93,根据消减值可以区分出直链淀粉含量高低的品种,低或中低直链淀粉含量的品种的消减值一般为负值或较小的正值,中高或高直链淀粉含量的品种的消减值是正值。消减值和崩解值与胶稠度相关系数分别为-0.91和0.81,由此可根据消减值和崩解值来判断稻米食用品质的优劣。     

双波长比色法测定不同产地和品种青稞中直链淀粉和支链淀粉的含量

利用一种更简便、准确的双波长比色法来测定不同产地和品种青稞中直链淀粉和支链淀粉的含量,以此代替以往复杂繁琐的样品前处理过程。根据双波长比色原理——若溶液中某溶质在两个波长下均有吸收,则两个波长的吸收差值与该溶质浓度成正比,以及根据直链淀粉和支链淀粉与碘试剂作用分别产生纯蓝色和紫红色的性质,用紫外分光光度计对两种淀粉与碘试剂的反应液进行全波长扫描(450~900nm),用作图法在同一个坐标系里确定其各自的测定波长和参比波长。结果测得直链淀粉的测定波长和参比波长分别为560nm和506nm,支链淀粉的测定波长和参比波长分别为545nm和722nm。青稞中直链淀粉和支链淀粉分别在0.20~0.59mg和0.50~3.00mg范围内具有良好的线性关系(R2=0.9993和R2=0.9995),平均加样回收率分别为91.14%和91.73%,RSD分别为1.70%和2.25%(n=9)。该方法简便、准确、稳定性和重现性好,适用于测定青稞中直链淀粉和支链淀粉的含量,可为青稞的质量控制提供依据。      

磷酸酯化直/支链淀粉的性能测试与比较

为了研制应用性能可以在一定范围内定量调整的磷酸酯化淀粉,采用干法制备了磷酸酯化直链淀粉和磷酸酯化支链淀粉,并用IR光谱、X-衍射光谱进行了表征;测定和比较了质量比分别为3∶1、1∶1、1∶3的磷酸酯化直/支链淀粉的透光率、抗凝沉性、冻融稳定性、吸水性、吸油性、黏度及黏度热稳定性等应用性能。试验结果表明:磷酸酯化直/支链淀粉的透光率、抗凝沉性、冻融稳定性、吸水性、黏度及黏度热稳定性随着磷酸酯化支链淀粉比例的增加而逐渐增大,吸油性则逐渐减小。