Insights into the swelling process and drug release mechanisms from cross-linked pectin/high amylose starch matrices

Cross-linked pectin/high amylose mixtures were evaluated as a new excipient for matrix tablets formulations,since the mixing of polymers and cross-linking reaction represent rational tools to reach materials with modulated and specific properties that meet specific therapeutic needs.Objective:In this work the influence of polymer ratio and cross-linking process on the swelling and the mechanism driving the drug release from swellable matrix tablets prepared with this excipient was investigated.Methods:Cross-linked samples were characterized by their micromeritic properties(size and shape,density,angle of repose and flow rate)and liquid uptake ability.Matrix tablets were evaluated according their physical properties and the drug release rates and mechanisms were also investigated.Results:Cross-linked samples demonstrated size homogeneity and irregular shape,with liquid uptake ability insensible to pH.Cross-linking process of samples allowed the control of drug release rates and the drug release mechanism was influenced by both polymer ratio and cross-linking process.The drug release of samples with minor proportion of pectin was driven by an anomalous transport and the increase of the pectin proportion contributed to the erosion of the matrix.Conclusion:The cross-linked mixtures of high amylose and pectin showed a suitable excipient for slowing the drug release rates.

Effect of Cold-Water Irrigation on Grain Quality Traits in japonica Rice Varieties from Yunnan Province,China

The response of grain quality traits to cold-water irrigation and its correlation with cold tolerance were studied in 11 japonica rice varieties from Yunnan Province, China. The results indicated that the response of grain quality traits to the cold-water stress varied with rice varieties and grain quality traits. Under the cold-water stress, grain width, chalky rice rate, whiteness, 1000-grain weight, brown rice rate, taste meter value, peak viscosity, trough viscosity, breakdown viscosity and final viscosity significantly decreased, whereas grain length-width ratio, head rice rate, alkali digestion value, protein content and setback viscosity markedly increased. However, the other traits such as grain length, amylose content, milled rice rate, peak viscosity time and pasting temperature were not significantly affected by the cold-water stress. Significant correlations were discovered between phenotypic acceptability and cold response indices of taste meter value, protein content, peak viscosity and breakdown viscosity. Therefore, it would be very important to improve the cold tolerance of Yunnan rice varieties in order to stabilize and improve their eating quality.

Starch Digestibility and Functional Properties of Rice Starch Subjected to Gamma Radiation

This study investigated the effect of gamma radiation on the digestibility and functional properties of rice starch.Rice cultivars IRGA417 and IAC202 were used for isolation of starch by the alkaline method.Starch samples were irradiated with 1,2 and 5 k Gy doses of ^(60)Co at a rate of 0.4 k Gy/h.A control sample,which was not irradiated,was used for comparison.Irradiated and control starches were characterized by in vitro starch digestibility,total dietary fiber,color,water absorption index,water solubility index,syneresis,swelling factor,amylose leaching,pasting properties and gel firmness.Irradiations changed starch digestibility differently in either cultivar.Increasing radiation doses promoted increase in the color parameter b*(yellow),elevation in the capacity to absorb water,and solubility in water as well as the amylose leached from granules for both cultivars.Pasting properties showed a decrease that was proportional to the dose applied,caused by the depolymerization of starch molecules.Gel firmness of the starch from IAC202 was inversely proportional to the radiation dose applied,whereas for IRGA417,there was a reduction at 5 k Gy dose.Rice starches can be modified by irradiation to exhibit different functional characteristics and they can be used by the food industries in products such as soups,desserts,flans,puddings and others.

Acetylation of Starch Extracted from Rejected Fruits of <i>Musa ×paradisiaca L.</i>to Obtain a Pharmaceutical Disintegrant

There are many natural sources to obtain pharmaceutical grade starch, one of which is banana (Musa × paradisiaca L.);nevertheless, the use of native starch has certain disadvantages compared to modified starches, whose disintegrating properties are better. In this study, starch extracted from rejected fruits of Musa × paradisiaca L., was modified by acetylation, under the following optimized experimental conditions: 130 mL acetic anhydride, 3 mL sodium hydroxide 50% p/v for each 15 grams of native starch, at 123℃ during 3 hours. The reaction resulted in a modified green banana starch with twice as much swelling capacity compared to unmodified (native) starch;acetylation was verified by infrared spectroscopy and degree of substitution of acetyl groups by back titration. The dissolution profiles of Ibuprofen tablets made with banana modified starch and commercial disintegrant, have no differences according with their similarity factor, f2. It is concluded that it is feasible to use green banana starch modified through acetylation as a pharmaceutical disintegrant.

Synthesis and Characterization of Hydrogels Based on Potato Starch/Poly(vinyl Alcohol)/N,N′-Methylenebisacrylamide

Several hydrogels were synthesized by free-radical polymerization in an aqueous medium based on potato starch(PS),poly(vinyl alcohol)(PVA),and N,N′-Methylenebisacrylamide(MBAm),being possible to study these hydrogels as a function of the proportion of components incorporated.In this way,the products generated from the synthesis were characterized by swelling and deswelling kinetics,the first swelling being verified with Schott and statistical models,allowing to contrast the proximity between the experimental and theoretical behavior.Additionally,water retention in soil(R%),spectroscopy(FTIR),morphological(SEM),and thermal(TGA and DSC)analysis allowing to know the intrinsic characteristics of the material,increasing in general terms the knowledge of this type of material.In this context,it was possible to verify the characteristics and effectiveness of the synthesis and crosslinking of the main components.The experimental results obtained show that the synthesized hydrogels present representative swellings consistent with kinetic and statistical models,optimal thermal stability depending on the amount of crosslinker,and excellent water retention in environments such as soil,presenting it as an excellent alternative to be used in agro-industrial applications in an eco-friendly way.

水稻α-淀粉酶基因的表达模式与颖花开放的关系

【目的】淀粉降解与水稻浆片膨大和颖花开放过程密切相关,探究α-淀粉酶基因在颖花开放过程中的作用,为杂交水稻制种效率及产量的提高提供理论依据。【方法】在水稻扬花时,利用稀释碱性品红溶液进行离体穗子吸水试验,观察碱性品红在颖花中残留的组织,通过碘-碘化钾染色法确定11—14期(依据雄蕊发育分期)淀粉粒的分布变化,并通过RT-PCR、RT-qPCR和GUS报告基因检测多个α-淀粉酶基因在此期间的时空表达模式。【结果】水稻颖花开放前,内外稃片通过相互嵌合的钩合槽(marginal tissues of palea,mtp)将浆片和雌雄蕊封闭在内。当颖花开放时,浆片快速膨大,使得内外稃片的钩合点松开。扬花期间,离体穗子在稀释碱性品红溶液中吸水后,碱性品红染料主要残留在内外稃片钩合槽和浆片相连处组织以及花丝中。碘染试验显示,在12期(颖花开放前),淀粉粒主要分布在雄蕊和内外稃片钩合槽,浆片中也有少量淀粉粒,在13—14期(颖花开放中),内外稃片钩合槽和浆片中的淀粉粒均降解。RT-PCR分析发现OsRAmy2A和OsRAmy3D的表达量从12期开始上升,至13—14期表达量显著增强,到受精后1 d(1 day after pollination,DAP1)表达量又明显下降,OsRAmy3E和OsRAmy3F在此过程中持续表达,OsRAmy3F表达量弱于OsRAmy3E。RT-qPCR分析显示,在11—14期,OsRAmy2A表达量变化最显著,其次是OsRAmy3A和OsRAmy3E,OsRAmy3F的表达量变化幅度最不明显,OsRAmy2A和OsRAmy3A在13—14期表达量显著增加,而OsRAmy3E和OsRAmy3F在不同时期均表达,在13—14期表达量略有升高。在12期,OsRAmy2A主要在内外稃以及内外稃片钩合槽上表达,在13—14期主要在内外稃片钩合槽、浆片以及花丝上表达。【结论】水稻颖花开放过程中淀粉粒在mtp和浆片中明显降解,与OsRAmy2A、OsRAmy3D等α-淀粉酶基因时空表达模式相对应,可能与水稻浆片膨大导致颖花开放过程密切相关。

小麦淀粉与面条质量关系的研究进展

小麦淀粉品质对白盐面条的质量(尤其是煮后的感官特性)有重要影响。直链与支链淀粉的含量及比例是影响面条质量的重要因素,是造成不同小麦品种淀粉糊化和膨胀特性及面条质量差异的物质基础。较低直链淀粉含量的小麦粉具有较好的糊化和膨胀特性,制作的面条煮制时吸水率高,烹调损失低,具有较高的感官评分。优质白盐面条的直链淀粉含量应在22%左右。峰值黏度、稀懈值、峰值时间是影响面条质量的重要糊化参数,这3项参数高的小麦粉适合制作优质面条。高膨胀势或膨胀体积的小麦粉制作的面条中等偏软,光滑且富有弹性,可以作为面条用小麦的重要选择标准。一般认为,直链淀粉含量较低、峰值黏度和稀懈值高、峰值时间长、膨胀势或膨胀体积高的小麦粉适合制作优质白盐面条。其中,直链淀粉含量、峰值黏度和膨胀势是优质面条小麦评价的关键品质性状。

小麦淀粉膨胀体积和直链淀粉含量的研究

为了了解陕西关中小麦品种与澳大利亚西部小麦品种间淀粉品质的差异 ,以参加陕西关中小麦品种区域试验的 15个小麦品种 (系 )、西澳 8个面条用小麦品种为材料 ,通过比较和相关分析的方法研究了小麦淀粉的膨胀体积、直链淀粉含量及其相互间的关系。结果表明 ,陕西关中和澳大利亚西部小麦品种的淀粉膨胀体积平均值分别为 2 8.91和 2 8.72 m l/g,直链淀粉含量平均值分别为 2 6 .39%和 2 6 .14 % ;小偃 5 0 3、小偃 137和西农 383表现出较高的淀粉膨胀体积 (依次为 31.90、31.6 7和 2 9.5 9ml/g)和较低的直链淀粉含量 (依次为 2 0 .39%、2 3.85 %和2 4 .2 5 % ) ,已达到了澳大利亚小麦品种的水平 ;膨胀体积与直链淀粉含量呈极显著负相关。

小麦品种Waxy蛋白亚基缺失类型若干淀粉性状研究

研究了小麦不同Ｗａｘｙ蛋白亚基缺失类型品种（系）与正常类型的直链淀粉含量和膨胀势的平均表现。结果表明，多数Ｗａｘｙ蛋白亚基缺失类型品种（系）的直链淀粉含量和膨胀势分别低于和高于Ｗａｘｙ正常型，并在不同缺失类型间存在差异。讨论了Ｗａｘｙ蛋白亚基缺失类型材料的利用价值等问题。

三偏磷酸钠交联马铃薯淀粉颗粒膨胀历程及溶胀机理研究

本文利用淀粉与三偏磷酸钠的交联反应,通过控制交联反应程度,成功地控制了交联淀粉颗粒地膨胀并使其停留在不同的溶胀阶段,详细地研究了处在不同溶胀阶段交联淀粉颗粒的结构特征和变化趋势,揭示了交联淀粉颗粒由高交联非糊化到低交联溶胀糊化具体地膨胀历程及溶胀机理,即交联马铃薯淀粉是以颗粒尾端为主的不均衡膨胀。

大米淀粉纯化工艺及其性质的研究

该文采用碱性蛋白酶对碱法制备得到的大米淀粉进行纯化,酶解条件为pH 9,温度45℃,酶与底物比48 AU/kg,时间60 min。大米淀粉中的蛋白质含量从2.87%降低到0.40%。扫描电镜分析大米淀粉的超微结构显示,碱性蛋白酶纯化处理后的大米淀粉中未见明显的蛋白质颗粒存在。比较纯化前后的大米淀粉发现,大米淀粉经过碱性蛋白酶纯化后,其溶解度和膨润力都明显增加。

小麦淀粉润胀过程中颗粒性质的研究

本文以郑州9023小麦粉为原料,采用湿法直接提取天然淀粉,研究小麦淀粉的形貌、润胀特性及其分子量分布。结果表明:郑州9023小麦淀粉是由直链淀粉、中间级分和支链淀粉组成。光学显微镜观察小麦淀粉颗粒呈圆盘形或椭圆形,观察到轮纹和脐点,小麦淀粉在不同糊化温度的糊化过程,偏光十字逐渐消失,糊化温度为80℃时,此时,偏光十字完全消失;在糊化过程中淀粉的粒径、溶解率和膨胀势均随加热时间的延长而增大,随温度的升高而升高。

关中小麦品种籽粒糊化特性研究

以参加陕西省关中小麦品种区域试验的 15个小麦品种 (品系 )为材料 ,研究了全麦粉、小麦粉和淀粉的粘度参数和膨胀体积 ,及各参数间的相关性。结果表明 :样品不同处理形式和添加AgNO3对糊化特性有较大影响。全麦粉与小麦粉峰值粘度呈极显著正相关 ;加AgNO3小麦粉与淀粉、加AgNO3全麦粉的峰值粘度显著正相关。小麦粉与全麦粉的膨胀体积呈显著正相关 ,但淀粉与小麦粉、全麦粉的膨胀体积不相关。全麦粉和淀粉的膨胀体积与其粘度参数不相关 ;小麦粉膨胀体积与其峰值粘度、冷糊稳定性、热糊稳定性呈极显著或显著正相关 ;加AgNO3小麦粉膨胀体积与其回生值呈显著正相关。以全麦粉、小麦粉和淀粉的膨胀体积和粘度参数进行聚类分析 ,结果表明 :不同处理形式下所得小麦品种聚类结果并不一致。这说明 ,小麦籽粒中其它组分或样品粒度对淀粉糊化特性有重要影响。

湿热处理对不同直链含量的玉米淀粉性质的影响

以普通玉米淀粉和高链玉米淀粉(Hylon V和Hylon VII)为研究对象,考察了湿热处理前后其抗性淀粉含量、直链淀粉含量、热力学性能、膨胀度及消化性等性质的变化.结果表明:湿热处理后3种玉米淀粉的抗性淀粉含量和直链淀粉含量均有所提高;湿热处理提高了3种淀粉的糊化温度和糊化焓,使糊化变得困难;湿热处理后偏光十字没有消失,部分淀粉颗粒的表面出现凹坑,十字中心部位强度减弱,直链淀粉含量越高,强度减弱越明显;湿热处理使3种淀粉的膨胀度和消化性降低.

影响谷蛋白溶涨指数测定因素研究

谷蛋白溶涨指数 (简称SIG)是一定量小麦粉在SDS乳酸溶液中溶涨、离心后的面粉重量与小麦粉原始重量的比值。该方法适宜应用于小麦不溶性谷蛋白含量的评价 ,进而评价小麦的焙烤特性、面条和通心粉的蒸煮特性。研究表明 ,SDS溶液仅对蛋白质起作用 ,能将蛋白质大分子分解成小分子 ,而淀粉在SDS溶液中不分解 ,淀粉对测定结果无影响。随着温度升高 ,谷蛋白溶涨指数呈增高趋势。对测定的样品用量、试剂用量进行调整 。

稻米淀粉的润胀特性研究

采用光学显微镜对淀粉颗粒在糊化过程中的润胀特性进行了研究。淀粉颗粒润胀具有松驰、膨胀和收缩 3个过程。松弛是糊化前淀粉的吸水和结构的松弛过程 ,膨胀是淀粉颗粒晶体熔融和直链淀粉脱离以及淀粉颗粒大量吸水的过程 ,收缩表明了直链淀粉脱离后颗粒内外压力差的变化 ,颗粒外部压力大于内部压力 ,致使颗粒被压缩。

淀粉接枝衣康酸/丙烯酸高吸水材料制备与性能

旨在为降低吸水材料成本、拓宽原料来源、提高生物降解性、减少对石油化工产品的依赖提供指导,以水溶液接枝共聚法制备了淀粉接枝衣康酸/丙烯酸高吸水材料(S/IA/AA),讨论了淀粉糊化条件、中和度、单体含量、反应温度等因素对材料吸水性能的影响,采用FTIR、SEM、EDX等对吸水材料进行表征。研究表明:淀粉糊化最佳条件为糊化温度80℃,糊化比为10g·g-1,糊化时间30min;吸水材料合成最佳条件为中和度50%,衣康酸40%,淀粉20%,引发剂为4×10-3mol·L-1,交联剂0.075%,反应温度50℃;利用40%衣康酸替代丙烯酸所制S/IA/AA同S/AA相比,其吸水性能有一定提高且保水性能优良。

三偏磷酸钠交联玉米淀粉颗粒膨胀历程及结构特征

利用淀粉与三偏磷酸钠的交联反应 ,通过控制交联反应程度 ,成功地控制了交联淀粉颗粒膨胀程度并使其停留在不同的溶胀阶段 ,详细研究了处在不同溶胀阶段交联淀粉颗粒的结构特征和变化趋势 ,揭示了三偏磷酸钠交联玉米淀粉颗粒的膨胀历程及结构特征 ,即随着淀粉颗粒交联程度的降低 ,颗粒的膨胀历程由中心脐点处爆裂膨胀方式转化为颗粒整体向外的均匀膨胀方式 .

高直链玉米淀粉的理化特性研究

【目的】研究高直链玉米淀粉的理化特性,为高直链淀粉玉米新品种的培育及高直链玉米淀粉的产业化开发利用提供参考。【方法】以源自13份高直链淀粉玉米自交系和1份普通玉米自交系的籽粒为材料,研究了高直链玉米淀粉和普通玉米淀粉的淀粉粒表型特征、热特性、糊化特性、溶解度和膨胀势的差异。【结果】普通玉米淀粉中直链淀粉含量为27.72%;高直链玉米淀粉中直链淀粉含量为44.22%~78.81%,可分为Ⅳ、Ⅴ、Ⅵ、Ⅶ4个级别。SEM结果显示,随着直链淀粉含量的增加,A型淀粉粒形态由饱满光滑、有蜡质光泽的球体或多面体变为皱缩无光泽的不规则多面体,B型淀粉粒则由饱满光滑的小球体逐渐变为无蜡质光泽的椭圆形,直至扭曲成不规则颗粒。随着直链淀粉含量的升高,初始温度(To)、峰值温度(Tp)、最终温度(Tc)、温变范围(To-Tc)逐渐升高,焓变(ΔH)则逐渐降低。普通玉米淀粉有明显的粘度峰,糊化曲线呈现出典型的'双峰'特征,高直链玉米淀粉的粘度峰随直链淀粉含量的增加逐渐消失,曲线呈'S'型。普通玉米淀粉和高直链玉米淀粉的溶解曲线和膨胀曲线都显示了相同的趋势,但溶解度和膨胀势随直链淀粉含量的增加而显著降低。【结论】与普通玉米淀粉相比,高直链玉米淀粉在淀粉粒形态、热特性、糊化特性、溶解度和膨胀势等方面都表现出了不同程度的差异,且直链淀粉含量越高差异越大。

利用^(60)Coγ辐射聚合技术研制淀粉型农用高吸水材料

利用60Co g 辐射聚合技术合成淀粉接枝丙烯酸盐高吸水材料。辐照剂量7 kGy左右、交联剂用量0.01墶?墶⑺芤旱膒H值为5—8、淀粉用量在10%—30%时制成吸水倍率可达600倍、性价比较高的农用高吸水材料。