微细化马铃薯淀粉的生物降解性能研究

用机械球磨方法制备不同粒度的微细化马铃薯淀粉,采用半生物体内模型系统研究它们的生物降解性能。结果表明,颗粒的微细化有利于淀粉的生物降解微细化程度越高,淀粉越易被降解。超细马铃薯淀粉颗粒具有良好的生物降解性能。通过控制粒度大小可调节淀粉的生物降解速度和降解程度。     

微细化淀粉颗粒形貌及显微结构分析

采用真空球磨设备,以食用级马铃薯淀粉、木薯淀粉及玉米淀粉为原料,制备不同粒度的微细化淀粉,并对淀粉粒度变化、形貌及聚集态结构等进行表征。扫描电镜形貌分析表明,淀粉颗粒在球磨处理过程中,其形貌特征发生了明显的变化,淀粉颗粒破碎首先发生在颗粒的缺陷处、裂纹处、结晶区处等应力相对集中的区域,当球磨处理时间继续增加时,会呈现一种细化与团聚并存的动态平衡;研究中还发现,淀粉在微细化处理中,并不单是淀粉表面薄层逐渐剥落的过程,大多淀粉颗粒呈现出大块层破碎、淀粉核心崩解等现象。     

机械力化学效应对马铃薯淀粉消化性能和抗酶解性能的影响

采用In-Vitro消化模型和美国谷物化学协会（AACC）的76－13标准方法,研究被机械球磨微细化的马铃薯淀粉的消化性能的抗酶解性能,探讨机械力化学效应对马铃薯淀粉酶反应活性的影响。结果表明,微细化使得马铃薯淀粉颗粒的消化速度大大加快,抗酶解淀粉含量降低。机械力化学效应可提高淀粉颗粒对酶的敏感性,增加反应活性。     

微细化马铃薯淀粉的理化性质

采用Brabender粘度计及化学分析技术等测试手段 ,探讨了马铃薯淀粉颗粒在机械球磨微细粉碎后理化性质变化的规律 .结果表明 ,微细化改变了马铃薯淀粉的糊化性质 ,使其糊化变易 .随球磨时间的延长 ,马铃薯淀粉的糊化温度不断降低 ;当球磨 5 0h后 ,常温基本能糊化 ,同时糊粘度大大降低 ,热粘度和冷粘度稳定性提高 .微细化还导致马铃薯淀粉与水的结合能力增强 ,溶解度、膨胀度和吸湿性提高 .     

非晶颗粒态马铃薯淀粉的结构特征及酶降解活性研究

本文采用扫描电子显微镜、光学显微镜等分析测试方法，以原淀粉为参照，对非晶颗粒态马铃薯淀粉的颗粒形貌以及酶降解过程进行了观察和研究，结果发现，在非晶化处理过程中发生了从内向外爆裂式膨胀而形成一条大而深的长条形的爆裂孔，以此爆裂孔为突破口，在酶作用下非晶颗粒态淀粉逐渐降解，直至淀粉颗粒的完全消失，而原淀粉具有致密的结晶结构，在相同条件下酶降解活性远远低于非晶颗粒态淀粉。     

酸解-球磨法制备小颗粒淀粉及形成机理研究

传统微细化小颗粒淀粉的制备采用原淀粉直接球磨的方法,耗时长,能耗高,产物易糊化。采用先酸解再球磨的新工艺制备了微细化小颗粒淀粉,并与玉米原淀粉、酸处理淀粉的物化性质进行了比较。结果表明,玉米原淀粉的表面积平均粒径为12.9μm,酸处理后淀粉的表面积平均粒径没有明显变化,而微细化淀粉的表面积平均粒径有显著降低;酸处理淀粉的结晶度较原淀粉有所增加,而酸水解后球磨淀粉结晶结构减弱,部分偏光十字消失,双折射强度减弱。     

马铃薯交联淀粉的制备与结构表征

以三偏磷酸钠为交联剂,水分散法制备了马铃薯交联淀粉,应用红外光谱、X射线衍射、扫描电镜和偏光显微镜等分析测试方法,观察和研究了不同取代度马铃薯交联淀粉的颗粒形貌及其结晶结构。结果表明,产物取代度随交联反应时间的延长而增大;交联反应主要发生在淀粉分子的无定形区,在结晶区也有一定程度的反应;随着取代度的增大,淀粉中受侵蚀的颗粒增多,颗粒表面的小凹痕数量明显增加,部分颗粒表面变粗糙,颗粒内部出现凹陷甚至爆裂;交联淀粉的偏光十字清晰易见;1 017.08cm-1的吸收峰强度加强,证实在淀粉中引入了磷酸根基团。     

不同品种马铃薯淀粉的多层次结构和理化特性研究

以5种不同来源的马铃薯淀粉为原料,采用扫描电镜、小角X射线散射、X射线衍射、流变仪、RVA黏度分析仪和质构仪,研究马铃薯淀粉的多层次结构和理化特性。结果表明:5种马铃薯淀粉颗粒形状都介于球形和椭球形之间,且表面光滑平整,但9728-04表面不平整;中薯五号淀粉颗粒最为致密,0623淀粉颗粒最为疏松;0687淀粉颗粒的半结晶层结构有序化程度最高,0623淀粉颗粒的半结晶层结构有序化程度最小;马铃薯淀粉有结晶区和非结晶区构成,且9728-04和中薯5号的结晶度较大,0687的结晶度最小;华薯一号的弹性模量最大,说明其弹性最高;0623的糊化温度最高,9728-04的糊化温度最低;五种马铃薯淀粉凝胶的质构特性表明9728-04淀粉凝胶的硬度最大,中薯五号的弹性和黏附性最大,0623的内聚性、胶黏性和咀嚼性最大,0687的回复性最大;透明度测定表明0687淀粉糊的透明度最大。最后,通过相关性分析发现马铃薯淀粉的结构与其凝胶的质构特性有一定的相关性。由于马铃薯品种的不同导致了马铃薯淀粉结构的不同,从而影响了马铃薯的理化特性。     

不同热处理方式下抗性淀粉形成机理研究

不同热处理方式对抗性淀粉的形成和淀粉的颗粒及结晶性质有较大影响。其中湿热处理前后淀粉的颗粒形貌变化较小。但淀粉的结晶结构发生一定程度的变化,表现为特征峰的部分融合、峰强度的下降以及结晶度的降低。其中马铃薯淀粉基本呈非晶状态。压热处理后淀粉,颗粒形貌已经完全发生了变化,颗粒破裂重组,不同淀粉颗粒中的链淀粉相互形成氢键,从而改变了原淀粉的结晶结构,从X射线衍射图谱我们可以看出,处理后淀粉有新结晶峰的形成。在过量水分条件下的压热处理有利于抗性淀粉的形成。     

酶解-球磨法制备微细化淀粉的性质研究

传统微细化小颗粒淀粉的制备采用原淀粉直接球磨的方法,耗时长,能耗高,产物易糊化。采用先酶解再球磨的新工艺制备微细化小颗粒淀粉,并与玉米原淀粉、原淀粉球磨淀粉的性质进行比较。结果表明:玉米原淀粉的表面积平均粒径为12.90μm,原淀粉球磨淀粉的表面积平均粒径略有增大,而酶解-球磨淀粉的表面积平均粒径显著降低;酶解-球磨淀粉的结晶结构受到一定程度的破坏,部分偏光十字消失,双折射强度减弱,结晶度显著降低。     

Effect of high hydrostatic pressure on modified noncrystalline granular starch of starches with different granular type and amylase content

Waxy corn (A-type pattern, amylopectin with trace amounts of amylase) and tapioca starch (C-type pattern, 17 g/100 g amylase content) were modified by High Hydrostatic Pressure (HHP) to produce noncrystalline granular (NCG) starch, respectively. The changes in the starch structure and properties occurring upon modified NCG after high-pressure treatment (300–600 MPa/30 min) were analyzed using polarized light microscopy (LM), differential scanning calorimetry (DSC), particle size distribution and scanning electronic microscopy (SEM). The resulting modified NCG starch took place when the 50 g/100 g starch suspension was treated under 450 MPa for the waxy corn starch with swelling degree of 57.07%, whereas 600 MPa for the tapioca starch with restricted starch swelling degree of 16.48%, indicating the stabilization effect of amylase. Also, they had reduced gelatinization temperatures, and lower pasting viscosities, which suggested that HHP had an effect on the physicochemical properties of native starch by destabilization, hydration and swelling.     

Milk production and nutrient digestibility by dairy cows when fed exogenous amylase with coarsely ground dry corn

The digestibility of starch provided by coarsely ground corn is often low, which reduces the digestible energy (DE) concentration of the diet. We hypothesized that adding exogenous amylase to diets based on coarsely ground dent corn would increase dietary DE resulting in greater milk production. Total-tract nutrient digestibility was measured in a partially replicated Latin square experiment (6 cows and 4 periods) with a 2 × 2 factorial arrangement of treatments. Diets had 26 or 31% starch with or without exogenous amylase (amylase was added to the concentrate mixes at the feed mill). In the low and high starch diets, coarsely ground dry corn (mean particle size = 1.42 mm) provided 43 and 62% of total dietary starch (corn silage provided most of the remaining starch). No treatment interactions were observed. High starch diets had greater dry matter (DM), organic matter, and energy digestibility than low starch diets, and diets with amylase had greater neutral detergent fiber digestibility than diets without amylase. Digestibility of starch averaged 88% and was not affected by treatment. A long-term (98-d) lactation study with 48 Holstein cows (74 d in milk) was conducted using 3 of the diets (low starch diets with and without amylase and the high starch diet without amylase). Addition of amylase to a diet with 26% starch did not affect intake, milk yield, milk composition, body weight, or body condition. Cows fed the diet with 31% starch had greater DM and DE intakes; yields of milk, fat, and protein; and feed efficiency than those fed diets with 26% starch. Milk composition was not affected by starch concentration. Adding exogenous amylase to a lower starch diet did not make the diet nutritionally equivalent to a higher starch diet.     

Visual Observation of Hydrolyzed Potato Starch Granules by α‐Amylase with Confocal Laser Scanning Microscopy

Porous starch was produced by digestion of freeze‐dried potato starch with α‐amylase from Bacillus sp. The surface structure of the granules became perforated and in the interior of the granules a capsule‐like cavity was formed, i.e. the hydrolyzed starch can be used as an encapsulant. The structure change of the granules was observed with confocal laser scanning microscopy and scanning electron microscopy. The degree of starch hydrolysis could be correlated with the Avrami equation. The activation energy of starch hydrolysis by α‐amylase was 83 kJ/mol.     

大米淀粉老化特性的研究进展

概述了近几年国内外对大米淀粉老化特性的研究。简要阐述了大米淀粉的老化机理,表明大米淀粉的老化可以划分为短期老化(short-term retrogradation)和长期老化(long-term retrogradation)两个阶段。然后介绍了直、支链淀粉、糖类、蛋白质、脂质、水分含量及温度等影响因素对大米淀粉老化的作用原理,其中重点介绍了直链淀粉含量的多少、支链淀粉结构及蔗糖、魔芋葡甘露聚糖(KGM)、β-葡聚糖、β-环糊精等糖类的食品添加剂对大米淀粉老化的影响机理。最后展望了大米淀粉老化性质未来的研究和应用方向。     

高直链玉米淀粉的糊化特性研究

目的研究水浴加热、微波加热和高压加热方法对高直链玉米淀粉糊化性能的影响,为高直链淀粉的进一步开发和应用提供理论基础。方法以高直链玉米淀粉为原料,在过量水分存在条件下,分别采用水浴加热、微波加热和高压加热制备高直链玉米淀粉糊,分别研究不同温度和微波功率下,高直链玉米淀粉糊碘兰值和酶解力随糊化时间增加的变化规律。结果水浴加热、微波加热和高压加热糊化过程中高直链玉米淀粉的碘兰值和酶解力均随时间的延长呈上升趋势,微波加热高直链玉米淀粉糊的碘兰值和酶解力低于高压加热但高于水浴加热,微波加热淀粉的糊化速度大于水浴加热和高压加热。结论高压加热淀粉糊化效果好,淀粉的糊化程度高,是使高直链淀粉完全糊化的较好方法。     

微波辅助提取马铃薯淀粉及其特性研究

微波辅助提取马铃薯淀粉,并对淀粉化学组成及特性进行分析。通过单因素和正交试验研究微波功率、微波时间、马铃薯破碎粒度及料水比对马铃薯淀粉提取率的影响。结果表明：各因素均对马铃薯淀粉提取率具有极显著影响;马铃薯处理量300g,在微波功率500W、微波时间4min、马铃薯破碎粒度0.246mm、料水比1:1(g/mL)时,马铃薯淀粉提取率高达93.85%,比传统方法增加6.31%。马铃薯淀粉蛋白质含量0.13%,直链淀粉含量34.60%,颗粒形状为椭圆形、扇形或圆形,平均粒径23.1μm,峰值黏度1332BU,溶解度、膨润力及透明度降低,凝沉性提高。     

Optimisation of porous starch preparation by ultrasonic pretreatment followed by enzymatic hydrolysis

Porous starch granules were formed by the partial hydrolysis of starch using amylase. Fungal amylase and corn starch were chosen as the original amylase and substance from different sources, respectively. Ultrasonic technique as an assistant of enzymatic hydrolysis was used to pretreat raw starch. Scanning electron microscopy was used to examine the structure of native and treated starch, revealing the size of the pores in each occasion. The extent of enzymatic hydrolysis (y%) was markedly enhanced by statistical optimisation of enzymatic conditions. A significant influence of amount, temperature and pH of enzyme has been noted with Plackett–Burman design. It was then revealed with response surface methodology (RSM) that 503.26 U (g substance)^?1 amount of enzyme, temperature of 55 °C and pH of 5.1 were optimum. This optimisation strategy led to the enhancement of y% from 53.4% to 61.38%.     

交联微孔淀粉基本性质的研究

微孔淀粉是一种功能材料。文中运用电子显微镜、X-衍射、布拉班德粘度仪等分析仪器对交联微孔淀粉颗粒形态、晶体结构、理化特性、糊化特性进行研究。结果表明淀粉经交联、酶等处理后影响到颗粒表面及内部,但未影响到晶体结构;交联微孔淀粉的孔径、溶解度、溶胀度及吸水能力和吸油能力均明显改善,同时提高了淀粉的结构性能。证明了用先交联后微孔化处理的方法改善微孔淀粉的结构强度和吸附功能是可行的。     

淀粉类酶降解鲜烟叶中淀粉的研究

为降低烤后烟叶中淀粉含量,研究了烘烤过程中外加淀粉类酶对淀粉降解的影响.结果表明,烘烤过程中,通过外加淀粉类酶来降解烤烟中的淀粉是有效的.烘烤变黄初期,不同外加淀粉类酶烟叶淀粉降解动态基本一致;变黄后期至定色前期,淀粉降解随外加酶量增加而加剧.烤后烟叶淀粉含量随外加酶量增加而减少,水溶性糖和还原糖含量随外加酶量增加而增加.方差分析表明,不同处理烤后烟叶之间淀粉含量存在极显著差异.多重比较结果表明,K326品种适宜的外加酶量为(6 60)U/g;HD品种适宜的外加酶量为(8 80)U/g.     

Some Enzyme Properties of Raw Starch Digesting Amylases from Streptomyces sp. No. 4

Streptomyces sp. No. 4 produce two forms of amylase that attack raw cassava starch. Both forms, amylase‐1 and amylase‐2, were purified by starch adsorption, affinity chromatography, and ion exchange chromatography. The molecular weights of amylase‐1 and amylase‐2 as determined by SDS‐PAGE were 56 kD and 77 kD, respectively. Optimal enzyme activities occurred at pH 5.5 and at 50°C for amylase‐1 and at 45°C for amylase‐2. The activation energy of amylase‐1 and amylase‐2 were 67 and 42 kJ/mol, respectively. Hg²⁺ and pCMB inhibited both enzymes, whereas 2‐mercaptoethanol activated only amylase‐2. EDTA inhibited amylase‐1 but activated amylase‐2. The main product of hydrolysis of raw cassava starch by amylase‐1 was maltose, followed by maltotriose, maltotetraose and dextrin. Amylase‐2 cleaved raw cassava starch to produce glucose and maltose as main products. Both amylase‐1 and amylase‐2 are α‐amylases, as shown by the fast disappearance of iodine staining, the corresponding reaction products and the ability of both enzymes to hydrolyze crosslinked blue starch.