微波改性高链玉米淀粉颗粒的抗消化性能与结晶结构的关系

通过控制不同的微波作用条件,获得了不同抗消化性能的微波改性高链玉米淀粉颗粒.并采用偏光显微和X射线衍射技术对不同抗消化性能的微波改性高链玉米淀粉颗粒的结晶结构进行了研究.结果表明,经微波改性后,高链玉米淀粉偏光十字和结晶形态都发生了改变,随着抗消化性能的提高,其偏光十字明显减弱,结晶形态从B型向V型转变.     

RS4型抗消化淀粉的结晶结构及消化性能研究

利用偏光显微、X射线衍射等现代分析技术，研究了酯化改性后淀粉颗粒形貌和结晶结构的变化。结果表明，与HylonV玉米淀粉相比，酯化改性后得到的RS4型抗消化淀粉的颗粒形貌和结晶结构都受到不同程度的破坏，尤其导致了结晶形态由B型向V型转变。由此引起淀粉的消化性能发生改变，经体外模拟试验表明，RS4型抗消化淀粉在人工胃液和人工小肠液中都有良好的抗消化性能，且随着抗消化淀粉含量的增加，抗消化性能越显著，显示了其良好的结肠靶向性。     

微波改性玉米淀粉的制备及其粘度性质的研究

采用微波对玉米淀粉进行辐照,运用Brabender粘度计对微波改性玉米淀粉的粘度曲线进行了测定.考察了不同微波时间、微波功率及微波时淀粉的水分含量时淀粉糊粘度性质的影响,并与原淀粉进行比较.结果发现:随着微波时间的延长,功率的增大,淀粉水分含量的增加,淀粉峰值粘度均下降,凝沉性降低,热糊稳定性和冷糊稳定性都有不同程度的增加,糊化温度也有所提高.其中水分对淀粉性质的影响最为显著.     

微波对蜡玉米淀粉糊流变特性的影响

本文采用微波辐射对蜡玉米淀粉糊进行改性.利用旋转粘度计对微波改性前后蜡玉米淀粉糊的流变特性进行研究,探讨了不同的温度、微波功率和微波时间对蜡玉米淀粉糊流特性的影响规律.结果表明,微波作用对蜡玉米淀粉糊的流变特性有显著影响.蜡玉米淀粉糊为假塑性流体,经微波处理后,由于淀粉的质量浓度变小,粘度下降,致使蜡玉米淀粉糊的流动曲线趋向平直,有向牛顿型流体变化的趋势,且随着微波加热温度的升高、微波功率的增大和时间的延长,变化趋势越明显.     

水溶性薄膜包衣对高链玉米淀粉结构的影响

利用高链玉米淀粉为包衣材料,通过高温高压及喷雾干燥方式进行聚合物水溶性包衣,研究了高链玉米淀粉在聚合物水溶性包衣条件下抗消化性能和结晶结构的变化。结果表明,相对于原淀粉而言,经过聚合物水溶性薄膜包衣的过程后,高链玉米淀粉的抗消化性能提高,抗消化淀粉的含量可达到28%,偏光十字消失,结晶程度降低。通过调节包衣条件可以调节淀粉的抗消化淀粉性能,从而使淀粉包衣薄膜能够达到对药物的控制释放。     

微波法制备羟丙基多孔玉米淀粉工艺优化

采用微波法对玉米多孔淀粉原料进行处理,经过正交试验优化工艺,制备具有不同取代度的羟丙基玉米多孔淀粉。研究在微波作用下,淀粉乳质量分数、微波处理时间、微波功率以及环氧丙烷用量对产品取代度的影响。结果表明,用微波法制备羟丙基玉米多孔淀粉的最佳反应条件为微波功率300W、环氧丙烷用量(质量分数)6.90%、微波时间3min、淀粉乳质量分数30%,在该条件下制备的羟丙基多孔淀粉的摩尔取代度为0.0103。     

微波对玉米淀粉结构及理化性质的影响

本实验采用微波（累积能量值为1 680 J/g）处理不同的淀粉-水体系,观察淀粉颗粒形态的变化,并测定透明度、沉降物体积、吸水率、持水性、相对结晶度和流变特性等指标。结果表明,随着淀粉-水体系中水分质量分数的增加,淀粉颗粒的完整性和偏光十字逐渐减弱;与玉米淀粉相比,微波处理淀粉乳透明度、沉降物体积、吸水率和持水性明显增加;X射线衍射图谱表明微波处理后淀粉颗粒仍为A型而相对结晶度下降,说明微波处理破坏了淀粉的结晶结构;微波处理没有改变淀粉乳流体的类型,弹性模量均大于黏性模量,表明均以弹性性质为主。结论：微波处理淀粉-水体系对淀粉的颗粒结构和理化特征均有显著影响,本研究结果可为开发具有独特理化性质的改性淀粉或改进淀粉改性工艺提供实验与理论依据。     

湿热处理对不同淀粉理化特性的影响

以普通玉米淀粉、高直链玉米淀粉、马铃薯淀粉和绿豆淀粉为试验材料,研究湿热处理对不同淀粉颗粒形貌、颗粒大小、糊化特性以及抗消化特性的影响。结果表明,在淀粉乳水分含量为30%,在120℃处理湿热处理10h,不同来源的淀粉,其颗粒形貌变化不同,其中普通玉米淀粉和高直链玉米淀粉的部分颗粒间发生粘结,少许淀粉颗粒中出现了较小的颗粒,淀粉表面有较大的凹坑;马铃薯淀粉和绿豆淀粉部分颗粒形态发生变化,颗粒的脐点处出现凹坑、部分淀粉颗粒有破碎;但湿热处理前后淀粉的偏光十字没有明显变化。与原淀粉相比,不同来源淀粉经过湿热处理后淀粉糊的溶解度、膨胀度和透明度均降低,降低幅度因淀粉种类的不同而有差异。湿热处理能够提高抗性淀粉含量。湿热处理后淀粉的糊化特性发生变化,糊化温度升高,峰值黏度、低谷黏度和破损值降低。普通玉米淀粉和绿豆淀粉的最终黏度和回生值下降,马铃薯淀粉的最终黏度和回生值增大。     

微波氧化过程对氧化淀粉阻垢性能的影响

以玉米淀粉为原料,采用微波处理方式,以双氧水为氧化剂,对玉米淀粉进行改性,引入羧基、羰基等官能团,缩短氧化反应时间,得到高羧基含量、少盐残的氧化淀粉阻垢剂。通过微波功率、氧化剂用量、水分含量等单因素实验,研究其对氧化淀粉阻垢性能的影响,得出羧基含量、羧基-羰基比与氧化淀粉阻垢性能呈正相关。通过监测微波反应过程中水分含量、羧基、羧基-羰基比例的变化过程,反映淀粉微波氧化反应过程中的条件变化(水分含量、p H、温度)对氧化淀粉的氧化程度、溶解度、阻垢性能的影响机制。得到了冷水可溶、高阻垢性能的氧化淀粉。     

微波法玉米油酸酯淀粉合成工艺参数及性质的研究

以玉米淀粉为原料,盐酸为催化剂,油酸为酯化剂,微波处理合成玉米油酸酯淀粉。通过单因素试验考察油酸用量、微波功率、盐酸用量和反应时间对微波辅助玉米油酸酯淀粉合成工艺的影响,并对其物化性质和微观结构进行了研究。结果表明:较佳工艺方案为淀粉100 g(干基),水分质量分数48%,微波630 W,辐射时间5 min,油酸用量为6.5%,催化剂的加入量为0.12%。玉米油酸酯淀粉糊与原淀粉糊性能相比,黏度降低、透光率高、抗凝沉性好并具有较好的乳化性能。     

Localisation of Amylose and Amylopectin in Starch Granules Using Enzyme-Gold Labelling

The independent localisation of amylose and amylopectin in a range of dry and hydrated native starch granules with varying amylose content (0—70 %) has been indirectly visualised using enzyme-gold cytochemical markers. Increasing amylose content was clearly demonstrated to result in distinct changes in granule architecture. In the absence of amylose (waxy maize starch) a framework of closely packed concentric layers of amylopectin exists in the granules. Low amylose content (potato starch) results in alternating layers of densely packed amylopectin and amylose molecules. High amylose content (amylomaize starch) granules were shown to possess an amylopectin centre surrounded by an amylose periphery encapsulated by an amylopectin surface. Elongated granules without the amylopectin centre were also observed in high amylose starches suggesting a relationship between amylopectin, amylose and granule shape. A model of starch granule architecture is proposed where increased compartmentalisation of amylose and amylopectin is observed in granules containing increasing levels of amylose.     

微波对板栗淀粉结构和理化性质的影响

为探讨微波辐照对板栗淀粉颗粒结构和理化性质的影响,采用微波辐照板栗淀粉,通过扫描电镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、差示扫描量热仪(DSC)等研究微波处理不同时间后板栗淀粉的颗粒结构和理化特性。研究表明:与原淀粉相比,微波处理后板栗淀粉的微观形貌发生明显变化,但淀粉颗粒仍为C型晶体。随着微波处理时间的增加,直链淀粉含量增大,淀粉颗粒表面出现裂纹、孔洞和黏结越显著,淀粉颗粒的相对结晶度降低、红外光谱(1 047/1 022)cm~(-1)峰强度比值降低;淀粉膨胀度和透光率也随微波处理时间的增加而降低。DSC分析表明,微波处理80 s的淀粉相转变温度(T_o和T_p)降低、糊化焓(ΔH)减少。表明微波辐照对板栗淀粉的颗粒结构和理化特征均有显著影响。     

Effect of Acid‐Methanol Treatment on the Physicochemical and Structural Characteristics of Cassava and Maize Starches

Physicochemical, structural and morphological characteristics of maize and cassava starches treated with 0.36% concentrated HCl in anhydrous methanol at 54ºC for 1–8 h were analyzed and compared. Average yield of modified starch was about 97% for both starches. The solubility of the acid‐methanol treated starches increased with temperature and after 3 h of treatment reached 93% for maize starch and 97% for cassava starch at 95ºC. After 8 h of treatment, the average size of the cassava starch granules decreased from 14.9 to 11.1 µm. The action of acid‐methanol on the maize starch was more subtle, reducing the granule average size from 11.8 to 11.3 µm. Scanning electron micrographs showed that the granule surfaces were rough and exfoliated after treatment suggesting exocorrosion that was more evident for cassava starch. From GPC, it was noted that amylose and amylopectin were partially degraded during treatment. Starch crystallinity gradually increased with duration of treatment. The amylose content decreased from 21.4 to 18.8% and from 26.3 to 23.0% and the intrinsic viscosity was reduced from 2.36 to 0.21 and from 1.85 to 0.04 for cassava and maize starches, respectively. The gelatinization temperatures increased whereas pasting viscosities decreased with reaction time, especially for cassava starch. These results suggested that the attack of acid‐methanol, which was more effective on cassava starch granules, occurred preferentially in the amorphous areas located in the granule periphery and composed of amylose and amylopectin.     

THE SUSCEPTIBILITY OF CEREAL STARCHES TO AMYLOLYSIS DURING GERMINATION AND MATURATION

During the maturation of normal and high amylose barley the susceptibility of the raw starches to attack by α-amylase remains constant until the moisture content of the grain falls below about 60%. Thereafter the starch develops a resistance to amylolysis which is directly proportional to the loss of grain moisture. The mean diameter of the starch granules of barleys and malt remains unchanged during digestion but the blue values of the residual starches decrease throughout. During the malting of wheat and barley the bulk of the starch solubilized is the amylopectin fraction although amylose is increasingly utilized when germination is prolonged. When high amylose barley is malted the blue value of the starch declines steadily throughout the growth period, suggesting that the spatial arrangements of the molecules within the granule influence the solubilization of the starch. The susceptibilities of wheats and normal and high amylose barleys to amylolysis were significantly lower than those of the corresponding malted products.     

Physicochemical Property of Starch-Soluble Dietary Fiber Conjugates and Their Resistance to Enzymatic Hydrolysis

Preparation and investigation of the resistant starch-soluble dietary fiber conjugates are very important, considering the different and meaningful physiological properties of resistant starch and soluble dietary fiber. In this study, the different starch-soluble dietary fiber conjugates were obtained by crosslinking using sodium trimetaphosphate, under the different treatments of conventional heat moisture and microwave heat moisture. The starch-soluble dietary fiber conjugates prepared under the treatment of conventional heat moisture almost completely resisted the hydrolysis of the amylolytic enzymes. However, the hydrolysis of the starch-soluble dietary fiber conjugates treated by microwave heat moisture was obvious. In the treatment of conventional heat moisture, soluble dietary fiber was combined into outer layer of the overall starch granule by the linking with 2-, 3-, or 6-OH of glucose in the amorphous region. This combination showed a large protective effect on the resistance to enzymatic hydrolysis of the whole starch granules. Whereas, in the treatment of microwave heat moisture, soluble dietary fiber was linked into the amorphous part of starch blocks derived from destructive starch granule, resulting in the conjugates with high homogeneity. Therefore, the as-prepared resistant starch-soluble dietary fiber conjugates under the treatment of conventional heat moisture have a potential to be used as new dietary supplement in the food industry.     

高链玉米淀粉改善面包的品质及消化性能

本文研究添加高链玉米淀粉对面包品质特性和消化性能的影响,以期为高链玉米淀粉等抗性淀粉在慢消化食品中的应用提供理论依据。结果表明,添加高链玉米淀粉能显著性提高面包的持水性和表面亮度,有利于提高消费者的接受度。但面包比容随高链玉米淀粉添加量的增加而逐渐显著降低。弹性、粘附性和恢复性未受高链玉米淀粉的影响,但硬度明显增加,添加10%和20%高链玉米淀粉的面包硬度升高为未添加时的1.2和1.8倍。面包的胶黏性和咀嚼性在高链玉米淀粉添加量小于10%时没有明显变化,而添加量进一步增加时,其胶黏性和咀嚼性逐渐显著提高。高链玉米淀粉能显著降低面包的消化速率,添加量为20%时面包的消化速率降低了54%。说明添加高链玉米淀粉会对面包的品质产生一定的影响,但合理控制其添加量可在面包的品质没有大幅降低的同时显著降低淀粉的消化速率。     

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.     

Changes in Starch Granules Trapped and Heated Using Optical Tweezers

A microscopic method to investigate the swelling process of individual starch granules heated in excess water is proposed. A starch granule focused under a light microscope is adjustably trapped using the optical tweezing of a near-infrared laser beam, which simultaneously heats the granule. Using this method, morphological changes in starch granules during heating were continuously recorded and quantitatively analyzed by image-processing techniques. The changes in granules of domestic wheat starches with differing amylose content were investigated under irradiation by the laser beam at constant optical power. The shapes of swollen granules of waxy wheat starches were observed to be distinctly different from those of non-waxy starches. Numerical indicators, specifically the time constant of swelling for the granule and its swelling magnification, were also obtained. These showed little relation to the pasting profiles of the same starches, obtained with a Rapid Visco Analyser.     

Structural Change of Maize Starch Granules by Ball-mill Treatment

Effect of ball-mill treatment on physical properties and molecular change of maize starch granule was investigated. Ball-mill treatment was done by rotary type mill, and species of maize starch are normal, waxy and high amylose (amylo). Running time of the treatment is 0–320 h. Starch granules loss smoothness on surface and became rough, even though their changing speed was different among the three species. But, they retained whole figure and size after 320 h treatment in the all cases. Amylase susceptivity and water absorption activity were measured. Structural change of starch components was compared among the three species with X-ray diffraction, DSC and GPC. High Performance An-ion Exchange Chromatography (HPAEC) pattern of debranched sample treated with ball-mill for 320 h showed that formation of very short chain in amylopectin is little. ¹³C solid-NMR spectra suggest that disruption of molecules of amylopectin and amylose with ball-mill might occur at their glycosidic linkage. However, very slight radical was observed by Electron Spin Resonance spectroscopy (ESR) in the case of 320 h sample.     

微波复合酶解改性对小米淀粉结构表征及其理化特性的影响

本文以小米淀粉为原料，采用微波、酶解、微波复合酶解三种方法改性淀粉。从淀粉颗粒形貌、偏光特性、结晶结构、短程有序性、粒径分布等方面对小米淀粉进行结构表征，测定其直链淀粉含量、溶胀力与透明度等指标以分析小米淀粉的理化特性。结果表明：改性后，小米淀粉的颗粒结构被破坏，偏光十字特性消失，结晶结构发生改变，但三种改性方法均不影响小米淀粉的基本官能团。其中，微波改性小米淀粉为A型晶体，酶解和微波复合酶解改性淀粉结晶型为B型，微波复合酶解改性淀粉的相对结晶度提高了35.32 %。改性淀粉的粒径、直链淀粉含量均有所提高，与原淀粉相比，微波复合酶解改性淀粉的直链淀粉含量增加了49.03 %。综上所述，与单一法相比，微波复合酶解法对淀粉颗粒结构和理化性质的改善效果最佳，这对于小米淀粉基食品的开发应用具有重要意义。