大米辛烯基琥珀酸酯淀粉中取代基团的分布

以大米原淀粉为原料,采用湿法工艺制备辛烯基琥珀酸淀粉酯(OSA-starch)。以浓度2.0 mol/L HCl处理不同时间,得到不同酸水解程度的辛烯基琥珀酸淀粉酯。采用扫描电子显微镜、X-射线衍射分析、X射线光电子能谱分析(XPS)等方法研究辛烯基琥珀酸酐(OSA)取代基团在大米淀粉分子中的分布情况。结果表明,随着酸水解时间延长,OSA淀粉取代度降低,黏度显著下降。与原淀粉相比,OSA淀粉及酸水解OSA淀粉的表面均出现凹陷现象,而颗粒结构与晶型结构均未发生改变,结晶度增加。XPS结果表明辛烯基琥珀酸酐变性大米淀粉的表面分布大量的辛烯基琥珀酸基团。辛烯基琥珀酸酐(OSA)基团与淀粉分子的作用主要发生在淀粉颗粒表面和淀粉分子的非结晶区域,且较少破坏淀粉的内部结构。     

变性淀粉系列讲座（十）：阳离子淀粉

淀粉与含有胺基、亚胺基、铵、锍或鏻基的化合物化学反应所制得的淀粉衍生物,称为阳离子淀粉。由于这些试剂都带有一个阳电荷基团,因此衍生物中使淀粉大分子上引入了一个或多个阳离子基团,从而具有高分子阳离子性能。这类反应的发现在1930年已有报道。但直到1952年才见到有实用价值的研究报告,1955年开始有了工业性的规模生产。它是一类很有价值的变性淀粉,对它的变性工艺及性能分析还在不断地进行着。在七十年代及八十年代的淀粉变性研究文献中,阳离子淀粉的研究古有重要地位。     

变性淀粉的种类及应用

变性淀粉是通过物理或化学方法使淀粉分子链被切断、重排或引入其他化学基团以改变其结构而获得的.经过变性的淀粉比原淀粉具有更优良的性能.根据变性方法,主要分为物理变性淀粉、化学变性淀粉、酶变性淀粉和天然变性淀粉.     

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。     

变性淀粉的生产原理、性能及应用

淀粉广泛存在于各类谷物种子和薯类、块茎之中。淀粉在工业生产各个领域的用途,也随着人们认识的不断提高而日益广泛。为了扩大应用淀粉的来原,使廉价的淀粉赋有优异的性能,各国相继研究了以化学方法在淀粉分子中引入各种基团,对淀粉进行变性处理。现已开发的变性淀粉有:糊精、酸变性淀粉、氧化淀粉,交联淀粉、酯化淀粉、醚化淀粉,阳离子淀粉和淀粉接枝共聚物。下面着重介绍几种变性淀粉的生产原理、性能及用途。     

变性淀粉应用于粉丝中的研究进展

变性淀粉是将部分基团引入原淀粉中,使其性质发生改变,具有了粉丝改进所需的凝胶力强,分子链增长等特性,使粉丝弹韧性增强,煮沸损失减少,品质提升,被越来越多的应用于粉丝中。本文介绍了微波处理淀粉、交联淀粉、磷酸酯淀粉及复合变性淀粉等在粉丝生产中的作用及应用情况。     

接枝变性淀粉的分子结构设计

为合理设计接枝变性淀粉的分子结构,对接枝支链的主链结构、接枝支链的空间结构、接枝支链中的侧基和接枝支链的分子量及其分布等影响接枝淀粉分子结构的主要因素进行分析,指出:接枝支链的主链应为碳碳单键结构的线型长链;支链上侧基以疏水性酯基为主,辅以亲水性基团,分布尽量均匀;接枝支链的分子量适中,分布以略宽为宜.     

交联氧化乙酰化蜡质玉米淀粉性质的研究

以蜡质玉米淀粉为原料、三偏磷酸钠为交联剂、次氯酸钠为氧化剂、醋酸酐为乙酰化试剂,采用湿法工艺制备交联氧化乙酰化复合变性淀粉,并利用扫描电镜(SEM)及红外光谱仪(FT-IR)分析其淀粉颗粒的形貌及结构。结果显示:复合变性处理后的淀粉白度升高至97.2,糊透光率升高至71.0%,耐酸及抗剪切性能也有所改善。扫描电镜图表现了淀粉颗粒形貌的变化,红外光谱图中展现的各基团的特征吸收峰表明其分子结构发生了改变。蜡质玉米淀粉采用复合变性的处理手段,有益于增强其在食品加工领域的应用价值。     

木薯淀粉与木薯变性淀粉鱼糜加工性质的影响

本研究比较了木薯淀粉、木薯醋酸酯交联淀粉和木薯磷酸酯交联淀粉对鱼糜加工性质的影响。首先测定了2种木薯醋酸酯交联淀粉、2种木薯磷酸酯交联淀粉以及木薯淀粉的冻融稳定性、透光率、黏性、膨胀度和凝沉性等特性。然后将木薯淀粉和4种变性淀粉分别添加到鱼糜中,测定鱼糜冻融过程中的持水性、白度以及凝胶强度等品质特性。结果表明:木薯变性淀粉因引入了磷酸基、羧甲基等亲水性基团,在透光率、冻融稳定性、黏性和凝沉性等性质方面较木薯淀粉均有提高,添加木薯变性淀粉所得到的鱼糜制品白度、持水性和凝胶强度分别增加了17.7%、10.2%、77.7%。木薯变性淀粉较木薯淀粉更适合用于加工鱼糜。     

几种木薯变性淀粉凝胶化性质的研究

对木薯醋酸酯淀粉、磷酸酯淀粉和氧化淀粉的糊化性质、流变特性和凝胶强度等凝胶化性质进行了比较研究.研究表明:醋酸酯淀粉和磷酸酯淀粉的糊化温度与原淀粉相当,氧化淀粉的糊化温度降低.醋酸酯淀粉和磷酸酯淀粉糊具有剪切稀化特性,属假塑性流体,氧化淀粉糊呈牛顿流体的特征.3种变性淀粉糊的表观粘度受浓度、温度和pH值的影响,与木薯原淀粉相比,变性淀粉糊具有较好的耐热和耐酸碱稳定性.而凝胶强度因变性基团的不同,差异较大.     

Moisture profiles of wheat noodles containing hydroxypropylated tapioca starch

Wheat noodles were prepared using flour to which hydroxypropylated tapioca starch was added, and the effect of this addition on the moisture distribution within the noodles during cooking was examined using a digital image processing technique. The addition of the modified starch slightly increased the moisture content and narrowed the flat distribution near the noodle surface. The distribution features reflected the changes in the water absorption behaviour caused by the properties of the modified starch and the reduction in the gluten content. Addition of the modified starch lowered Young's modulus and the energy for 99% strain of the noodles in the texture analysis to, at maximum 35% and 65%, and decreased the breakability of the noodles. These changes in the moisture distribution and textural properties have been ascribed to changes in both the state of the starch granules near the surface and the structure of the gluten network.     

Synthesis of Starch Copolymers by Silicon Tetrachloride Plasma‐Induced Graft Polymerization

Corn starch was surface‐functionalized by 13.56 MHz RF SiCl₄‐plasma, in situ reacted with ethylenediamine for stabilization, and subsequently graft‐polymerized using dichlorodimethylsilane as monomer. SiCl₄‐plasma treatment was studied and discharge parameters were optimized. X‐ray photoelectron spectroscopy (XPS/ESCA), Fourier transformed infrared spectroscopy (FTIR), scanning electron spectroscopy (SEM), gas chromatography/mass spectroscopy (GC‐MS), and differential thermal analysis/thermal gravimetry (DTA/TG) proved the presence of a polydimethylsiloxane (PDMS) graft‐copolymer layer on the modified starch‐granule surfaces. These analyses show that the surface morphology of starch granules, the thermal properties, the swelling characteristic, and the hydrophilicity of starch were all changed due to the existence of a protective hydrophobic PDMS layer. It is suggested that the starch graft‐copolymer might find its applications as reinforcing component in silicone‐rubber materials for starch‐based composites.     

Changes in the structural and physicochemical characterization of pea starch modified by Bacillus-produced α-amylase

In this study, changes in structural and physicochemical properties of pea starch treated with Bacillus-produced α-amylase were determined. The results showed that enzymatically modified pea starch had lower amylose content and granule size but higher branching degree and relative crystallinity. After enzyme hydrolysis, the distribution of A and B1 chains slightly decreased, while the distribution of B2 and B3 chains increased lightly. Enzymatic hydrolysis preferentially occurred in the amorphous region and cannot change the crystalline structure of pea starch. Moreover, pea starch showed lower light transmittance, peak viscosity, breakdown viscosity, pasting temperature, shear viscosity, storage modulus and loss modulus, while the oil adsorption capacity and gelatinization enthalpy significantly increased with increasing α-amylase hydrolysis time. Correlation analysis indicated that α-amylase hydrolysis had different effects on different pea varieties. This research could provide ideas for exploring new applications for enzymatically modified pea starch in food industry.Industrial relevanceThis study found that Bacillus-produced α-amylase significantly changed the amylose content, granule size and viscosity of pea starch, which was helpful to further investigate the modified starch. This technology is expected to widen the applications of pea starch modified by Bacillus-produced α-amylase in food industry, for example as thickener, stabilizer and beverage, to improve the texture, stability and shelf-life of various food products.     

Characteristics of microencapsulated β-carotene formed by spray drying with modified tapioca starch,native tapioca starch and maltodextrin

Acid-modified tapioca starch, native tapioca starch, and maltodextrin were tested for their ability to serve as wall materials for encapsulating β-carotene. The modified tapioca starch had wider particle size distribution, toward the smaller diameters, as compared to its native starch and maltodextrin. Moisture content and water activity of microcapsules were found to be dependent on type of wall materials. There were differences in total β-carotene and surface β-carotene contents among samples. The total β-carotene was highest for modified tapioca starch while it was lowest for maltodextrin. The surface β-carotene was lowest for modified tapioca starch while it was highest for native tapioca starch. The modified tapioca starch was more effective than its native starch in β-carotene retention. Results obtained suggest that the modified tapioca starch can be considered as potential wall material for encapsulation of β-carotene.     

不同种类淀粉对罗非鱼鱼糜凝胶品质的影响

为了改善淡水鱼鱼糜制品的品质,以冷冻罗非鱼鱼糜为原料,分别添加4%木薯原淀粉、3种木薯变性淀粉（磷酸酯淀粉、羟丙基淀粉和乙酰化二淀粉磷酸酯）及复配木薯变性淀粉（乙酰化二淀粉磷酸酯与羟丙基淀粉质量比为3∶2）,考察淀粉添加对鱼糜凝胶质构、流变学特性、持水性及水分分布和微观结构等的影响,探讨不同种类淀粉对鱼糜凝胶品质的改善。结果表明,与对照组相比,添加5种淀粉均会显著降低罗非鱼鱼糜凝胶的白度（P<0.05）,但其凝胶强度、硬度和咀嚼性显著增大,凝胶持水性显著提高（P<0.05）,蒸煮损失率显著下降（P<0.05）,结合水含量显著增加（P<0.05）,凝胶微观结构更加均匀致密,且添加了复配木薯变性淀粉的凝胶质构特性最好,持水性最高。低场核磁共振成像和光学显微镜观察结果显示,不同种类的淀粉均能有效锁住鱼糜凝胶基质中的水分;升温过程中淀粉吸水膨胀,在鱼糜凝胶网络结构中起浓缩和填充作用;添加了复配木薯变性淀粉的鱼糜凝胶结构最致密均匀。因此,添加复配木薯变性淀粉可以有效改善罗非鱼鱼糜制品的品质,为淡水鱼鱼糜制品的开发提供了理论支撑。     

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。     

Effect of Modified Starches on Rheological Properties of Ketchup

The aim of this work was to study the effect of commercial modified starches of different origin on rheological properties of ketchup. The following starches were used to produce the ketchup samples: chemically modified potato (acetylated distarch adipate from potato starch), waxy maize (acetylated distarch adipate from waxy maize starch and hydroxypropyl distarch phosphate from waxy maize starch), and cassava (acetylated distarch adipate from cassava starch) starches and physically modified cassava and waxy maize starches (physically modified cassava starch and physically modified waxy maize starch). The SEM microphotographs revealed that swollen or disrupted starch granules were present in the ketchup samples. As was evaluated by particle size distribution analysis, two peaks characteristic for different starch granule sizes were observed, the first peak at about 100 μm for ketchup thickened with potato starch and the second one at about 50 μm for the rest of the samples. Ketchups showed non-Newtonian, shear-thinning flow with tendency to yield stress. Values of the rheological parameters describing the flow curves significantly correlated with Bostwick consistency. Ketchup samples exhibited different susceptibility for temperature changes, while values of flow activation energy were from 4.18 to 9.00 kJ/mol. On the basis of mechanical spectra, it is noted that values of G′ were higher than these of G″ showing that elastic properties dominated over the viscous ones. Ketchup samples exhibited properties of weak gels which were estimated from the values of G′ and G″ moduli and their relation and from values of tangent of phase angle (tan δ = 0.14???0.37). Principal component analysis revealed both similarities and differences in rheological behavior of the examined ketchup samples thickened with different modified starches.     

预糊化变性淀粉在麻糬面包中的应用

本文研究了预糊化木薯变性淀粉、预糊化马铃薯变性淀粉、预糊化玉米变性淀粉和预糊化大米粉对麻糬面包的感官评价、比容、弹性的影响,分析了预糊化变性淀粉的布拉班德粘度曲线,结果表明,预糊化木薯变性淀粉与预糊化马铃薯变性淀粉制作的麻糬面包口感及外观较好,而预糊化玉米变性淀粉与预糊化大米粉制作的产品口感不佳、比容小,预糊化木薯变性淀粉与预糊化马铃薯变性淀粉质量比为1:1时,麻糬面包加工性能好、口感清爽、弹性强、比容较大、保型性佳。     

小麦氧化-酯化淀粉的制备及其性质的研究

以醋酸酐为酯化剂,对小麦氧化淀粉进行酯化,研究酯化程度与反应条件的关系,测定粘度性质和结构特征.研究表明,反应体系pH、醋酸酐用量和氧化淀粉氧化程度的影响比较大.淀粉经氧化-酯化复合变性后,颗粒受到了更大程度的破坏,存在明显的酯羰基;复合变性后的淀粉更易糊化,糊的粘度有所降低,稳定性更好.