颗粒状冷水可溶淀粉对豆类淀粉糊化及凝胶特性影响

研究颗粒状冷水可溶淀粉对绿豆淀粉和豌豆淀粉糊化特性及凝胶特性影响。通过对RVA和TPA数据分析,表明添加颗粒状冷水可溶淀粉后,二种豆类淀粉糊化温度随颗粒状冷水可溶淀粉添加量增加而升高,其峰值粘度、谷值粘度、终值粘度也随添加量增加而呈显著增大趋势;且添加颗粒状冷水可溶淀粉后,二种豆类淀粉凝胶硬度均呈显著下降趋势,而弹性则并未发生明显变化。     

湿热处理对玉米淀粉性质的影响

研究了湿热处理对不同直链淀粉含量的普通玉米淀粉?高直链玉米淀粉和蜡质玉米淀粉性质的影响。试验证明,经湿热处理后,三种玉米淀粉的颗粒形状都没有发生明显的变化,偏光十字也没有消失,但表面出现一些裂纹;湿热处理不会改变三种玉米淀粉的晶型,但经湿热处理后玉米淀粉的晶体结构变强,糊化温度提高,糊黏度降低。     

酸解-微波法制备RS3型玉米抗性淀粉工艺参数优化

以普通玉米淀粉为原料,经盐酸水解后进行微波处理,制备RS3型玉米抗性淀粉,采用单因素实验和响应曲面法相结合的方法对其工艺参数进行优化。以RS3型玉米抗性淀粉的产率作为评价指标,确定最佳的工艺参数。结果表明最佳工艺参数为:淀粉糊浓度29.1%,酸浓度1.5%,酸解时间2.4h,微波功率785.0W,作用时间18.0s,按以上工艺参数制备的RS3型玉米抗性淀粉的产率为12.3%。      

草酸侵蚀马铃薯回生淀粉制备晶种促进玉米淀粉回生的研究

回生淀粉具有积极的生理作用,本文采用草酸侵蚀马铃薯回生淀粉制备晶种促进玉米淀粉的回生,使得玉米淀粉的回生率从7.37%提高至11.46%。X-射线衍射表明经草酸侵蚀后马铃薯直链及支链回生淀粉均显示出了典型的B型衍射峰,即酸处理使得淀粉具有明显规则的形貌特征。以草酸侵蚀的马铃薯直链淀粉为晶种促进玉米淀粉回生长晶后,淀粉显示出了明显的B型衍射峰,且具有规则的外观形貌。这是由于分支度低的玉米淀粉分子在溶液中快速移动,向较规则形貌的马铃薯直链淀粉晶种上聚集并生长,这样既保持了马铃薯直链淀粉的晶体形貌又显著地提高了玉米淀粉的回生率。研究成果为促进玉米淀粉回生提供一条全新的途径。      

Physicochemical properties of cassava,potato and jicama starches oxidised with organic acids

The oxidising effects of organic (acetic, citric and lactic) acids on the physicochemical properties of starches from cassava, potato and jicama were investigated. Cassava starch oxidised with lactic and citric acids had the highest carbonyl contents (5.43 and 5.84 g kg^?1 respectively), while oxidised potato starch had the highest carboxyl contents. Oxidised jicama starch showed the lowest carbonyl and carboxyl contents. Oxidation increased the maximum viscosity of cassava starch (from 426.61 to 670.11 relative viscosity units (RVU)) and jicama starch (from 160.17 to 561.50 RVU) but decreased that of potato starch (from 669.44 to 206.92 RVU). When carbonyl and carboxyl groups were incorporated into jicama starch granules, the resistance of these granules to stirring at constant temperature (holding) increased, as did their final and retrogradation viscosities. However, the behaviour of oxidised cassava and potato starches, as indicated by a Rapid Visco Analyser, was different. The highest values of endotherm enlargement were found for native and oxidised jicama starch, while the lowest values were found for native and oxidised cassava starch. Native and oxidised potato starch had the highest enthalpy values (14.30–18.30 J g^?1), while jicama starch had the lowest (9.50–11.9 J g^?1). The high intrinsic viscosity of native potato starch was attributed to B‐type starch with a longer‐than‐average amylopectin chain length and a lower degree of crystallinity. Oxidised granules showed little erosion in the form of grooves; on the contrary, oxidation left the grains with a very smooth surface. Copyright © 2007 Society of Chemical Industry     

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)。     

Use of the resistance effect between retrograded starch and iodine for evaluating retrogradation properties of rice starch

A resistance effect between retrograded starch and iodine and its potential use for evaluating retrogradation properties of rice starch were investigated in this study. Our results showed that the resistance effect obviously occurred during the interaction of retrograded starch and iodine ions. The extent of the resistance was selected as a parameter to explore the kinetics of starch recrystallisation, indicating that the recrystallisation data obtained were suited to the Avrami equation (all correlation coefficients R > 0.99). Furthermore, the resistance was suitably employed to clarify some properties of starch retrogradation, including the rate constant (0.11 d⁻¹ ? k ? 0.17 d⁻¹) and the Avrami exponent (1.18 ? n ? 1.29). These results suggest that the resistance extent is able to provide potential data for measuring the degree of starch retrogradation.     

直链淀粉链长对蜡质玉米淀粉膜性质的影响

研究制备3种不同链长直链淀粉,并将其分别以8%,15%,25%的比例与蜡质玉米淀粉混合,采用流延法在23℃,相对湿度为85%的条件下干燥成膜。研究发现短链的脱支蜡质玉米淀粉(DWMS)与蜡质玉米淀粉混合成膜不发生相分离,而中等链长的玉米直链淀粉(MAM)和长链马铃薯直链淀粉(PAM)与蜡质玉米淀粉混合成膜时发生相分离。添加直链淀粉均可促进蜡质玉米淀粉结晶:蜡质玉米淀粉膜呈现无定形,DWMS添加比例由0%增加到15%时,淀粉膜结晶度增大,但添加比例进一步增加至25%时,结晶度下降;MAM与PAM的添加比例由0%增加到25%时淀粉膜的结晶度增加。淀粉膜结晶度与拉伸强度显著正相关(r=0.771),与穿刺强度显著正相关(r=0.780),与透油率显著负相关(r=-0.730)。DWMS的加入不影响蜡质玉米淀粉膜透光性和溶解性。随着直链淀粉链长以及添加比例的增加,淀粉膜透光率和溶解度降低。     

RVA分析碳酸钠对玉米淀粉和马铃薯淀粉糊化性质的影响

主要研究了碳酸钠(Na2CO3)对玉米淀粉和马铃薯淀粉糊化性质的影响。用粘度速测仪(RVA)分析在浓度为3%、6%的玉米淀粉(MS)和马铃薯淀粉(PS)中加入不同量的碳酸钠(0、0.02、0.04、0.06、0.08g)后的糊化参数。当将0.02、0.04gNa2CO3加入到浓度为6%MS中时,未测得第二个峰值粘度,而加入0.06、0.08g时,第二个峰值粘度出现,且发现加入Na2CO3对玉米淀粉和马铃薯淀粉糊化性质影响不同。用RVA分析3%、6%PS淀粉乳时,加入0.02gNa2CO3后,除糊化温度和回值外,其它RVA谱特征值显著降低,但进一步增加Na2CO3的量,谱特征值没有明显地变化。而对6%MS而言,由于Na2CO3的加入,使得峰值粘度、崩解值、回值增加而糊化温度降低。      

燕麦淀粉与常见淀粉的性质对比研究

以常见市售淀粉(小麦淀粉、玉米淀粉、土豆淀粉)为参比,研究了燕麦淀粉的透明度、凝沉性、冻融稳定性、溶解度、膨润力和糊化特性.结果表明:燕麦淀粉的透明度、凝沉性、冻融稳定性比小麦淀粉、玉米淀粉和土豆淀粉都要差.燕麦淀粉的溶解度在4种淀粉中是最高的,而膨润力是最低的.燕麦淀粉的糊化特性与小麦淀粉较接近.     

有机蒙脱土对热塑性氧化淀粉膜性能影响

以不同有机蒙脱土为增强剂,采用熔融挤出流延制膜工艺,研究不同有机蒙脱土对淀粉膜性能影响。结果表明,有机蒙脱土可有效提高淀粉膜拉伸强度和断裂伸长率、增加膜透明度、并降低膜的水蒸气透过率和水溶性。添加不同有机蒙脱土对膜性能有不同影响,DK_1和DK_5蒙脱土可有效提高膜断裂伸长率,DK_4蒙脱土可明显提高膜拉伸强度,DK_3蒙脱土可提高膜透明度,DK_2蒙脱土可有效降低膜的水蒸气透过率。     

Thermal and rheological properties of hydrogels prepared with retrograded waxy rice starch powders

Waxy rice starch dispersed in water (50% solids) was gelatinized by heating the dispersion at 121°C for 20 min, and retrograded by storing the paste at 4°C for 2 days. The starch gel was then freeze-dried and ground into powders. The retrograded starch powders were hydrated at 20–30% solid concentration at different temperatures (4 and 23°C), and then thermal and rheological properties were analyzed using the hydrogels. The gel hydrated at 4°C had an onset temperature of melting at 34.9°C, which was approximately 10°C lower than that observed for the gel hydrated at 23°C. The enthalpy value was greater for the gel hydrated at 4°C (14.2 J/g) than the gel hydrated at 23°C (8.8 J/g). The yield stress and consistency of the hydrogels were proportional to the solid concentration. The hydrogel prepared with 30% retrograded starch powders at 4°C displayed a thick creamy texture with retrograded starch crystals that could melt at a temperature range of 35–51°C. The thermal and rheological properties of the hydrogels exhibited the possibility for the retrograded starch powders to be used as fat mimetic in foods.     

氧化程度对羧酸型两性淀粉性能的影响

氧化型两性淀粉是一种新型的两性淀粉,同时包含羧基和阳离子基团。其制备采用两步法,先将淀粉阳离子化,再将阳离子淀粉氧化。阳离子淀粉最佳制备工艺为:淀粉乳浓度35%,醚化剂的用量为5%,pH11.6,反应先在50℃活化2h,再降温到45℃反应8h。通过添加不同量的NaClO到阳离子淀粉中制得羧基含量不同的两性淀粉,所得淀粉洁白,糊透明度高,稳定性强,凝沉性弱,热糊粘度也较阳离子淀粉明显下降,且这些性能均随羧基含量的增加而增强。     

交联和羟丙基改性对蜡质玉米淀粉糊化和流变性质的影响

以蜡质玉米淀粉为原料,制备了交联淀粉、羟丙基淀粉和交联羟丙基淀粉,通过扫描电子显微镜、X-射线衍射仪、快速黏度仪和流变仪等现代分析仪器分析了淀粉的结构、糊化性质和流变特性,探究了交联和羟丙基改性对淀粉的糊化和流变学性质的影响。结果表明:交联改性降低了淀粉的峰值黏度,增大了淀粉成糊温度、稠度系数和抗剪切性,淀粉黏弹性得到明显改善;羟丙基改性淀粉的峰值黏度提高,成糊温度、抗剪切性和结晶度降低,淀粉颗粒结构破坏;交联羟丙基改性淀粉具有交联淀粉的糊化和流变特性,但成糊温度和结晶度降低。     

Pasting and rheologic properties of potato starch and maize starch mixtures

This study characterized the pasting and rheologic behavior of potato/maize starch mixtures of various ratios. Pasting analysis using a Brabender Viscograph indicated that most important pasting parameters did not show a linear change that reflected the ratio of starches. A significant effect on final viscosities and setback was evident. The diameter distribution of starch granules that were heated to 70°C was determined by a laser particle size analyzer. The result suggested that the swelling of starch granules in the mixtures was reduced at the onset of gelatinization. Measurement of dynamic viscoelasticity measurement demonstrated that the mixtures showed slightly higher loss modulus than those seen for the control at small measuring frequencies. The mixture pastes with a high proportion of potato starch exhibited more pseudoplasticity and had a more significant thickening effect than either control paste. Nonadditive behavior was found by mixing potato and maize starch. This suggests that an appropriate blend of starches from diverse botanical origins may provide a simple practical avenue for manipulation.     

介质阻挡放电等离子体处理对玉米淀粉结构和功能性质的影响

目的 研究低温介质阻挡放电等离子体对高直链玉米淀粉和蜡质玉米淀粉的多尺度结构及功能性质的影响。方法 以高直链玉米淀粉(high-amylose corn starch, HAMS)和蜡质玉米淀粉(waxy maize starch, WMS)为研究对象, 采用介质阻挡放电等离子体技术, 控制输入电压110 V, 调节输入电流为0.8、1.0、1.2和1.4 A, 分别对淀粉粉体进行改性处理1 min, 探究两种淀粉在不同处理电流下等离子体场中的多尺度结构和理化功能性质的变化。结果 经过等离子体处理后, 两种淀粉颗粒的粒径增大, HAMS颗粒出现团聚现象, WMS的表面孔道和刻蚀现象更加明显, 淀粉乳的pH降低, 其溶胀力和成糊黏度均呈现降低的趋势, 其中WMS峰值黏度从3113.50 cP显著降低至795.50 cP。随着处理电流的增加, 两种玉米淀粉的吸热相转变焓值降低, 其中蜡质玉米淀粉焓值从(13.83±0.07) J/g降低至(8.20±0.03) J/g, 广角X射线衍射结果显示淀粉相对结晶度逐渐降低, 而傅立叶变换红外光谱法分析发现红外比值R1047/1022和R1022/995分别略微下降和升高。结论 等离子体处理对WMS的改性效率相比HAMS较大, 等离子体改性处理主要影响玉米淀粉的长程晶体结构, 而对短程双螺旋结构的影响较为有限。     

羟丙基糯玉米淀粉的制备及其性质的研究

以糯玉米淀粉为原料,环氧丙烷为醚化剂,在碱性条件下对羟丙基淀粉的制备工艺及其性质进行了研究.考察了醚化剂、膨胀抑制剂、pH、反应温度、反应时间对羟丙基淀粉取代度和反应效率的影响.实验结果表明,随着pH的增大,羟丙基淀粉的取代度和反应效率都增大;提高反应温度,羟丙基淀粉的取代度和反应效率都增加;增加环氧丙烷的用量,羟丙基淀粉的取代度随之增加,但反应效率呈下降的趋势;延长反应时间,淀粉的取代度和反应效率都呈上升趋势;增加硫酸钠的用量,羟丙基淀粉的取代度和反应效率都先增大,当硫酸钠用量超过12g时,随着硫酸钠用量的增加取代度和反应效率都降低.并且确定出最佳的反应条件:淀粉用量为100g时,pH为11.5,膨胀抑制剂12g,环氧丙烷10mL,反应温度50℃,反应时间20h.随着羟丙基糯玉米淀粉取代度的增加,其冻融稳定性、透明度、耐酸性、黏度热稳定性都增加.