应用RVA仪分析凉薯淀粉的糊化特性

利用快速黏度分析仪(RVA),研究淀粉质量分数、蔗糖质量分数、食盐质量分数、p H及转速对凉薯淀粉糊化特性的影响。结果表明:随淀粉质量分数的增大,淀粉的糊化温度降低,峰值黏度、谷值黏度、最终黏度增大,热稳定性先减弱后增强,凝胶性、凝沉性逐渐增强;随蔗糖质量分数的增大,淀粉糊化温度逐渐增大,峰值黏度、谷值黏度先增大后减小,热稳定性先增强后减弱,凝胶性、凝沉性逐渐增强;随食盐质量分数的增大,淀粉糊化温度增大,峰值黏度、谷值黏度、最终黏度逐渐降低,热稳定性、凝沉性先增强后减弱,凝胶性先减弱后增强;在酸性条件下,淀粉糊化温度较高,热稳定性、凝胶性、凝沉性稍强,在碱性条件下,峰值黏度、谷值黏度、最终黏度较高;随着转速的增大,淀粉糊化温度逐渐降低,峰值黏度、谷值黏度、最终黏度先增大后减小,热稳定性、凝沉性逐渐增强,凝胶性逐渐减弱。     

用RVA仪分析玉米淀粉的糊化特性

以玉米淀粉为原料,利用RVA(快速黏度分析仪),研究了不同浓度玉米淀粉以及在同一浓度下氯化钠、蔗糖以及转速对淀粉糊化特性的影响,并且在此基础上将RVA糊化程序改为多重RVA程序,然后观察对淀粉的特性的影响。结果表明:随着玉米淀粉溶液浓度的增加,起始成糊温度降低,淀粉糊的热稳定性降低,凝胶性增强。随氯化钠浓度增大,起始成糊温度逐渐升高,到达峰值时间有所延长,热稳定性明显提高,但凝胶性降低。当蔗糖浓度增加时,淀粉成糊温度、峰值黏度、最低黏度和最终黏度都随之增加,热稳定性增强,冷却过程中淀粉糊形成凝胶的能力减弱。玉米淀粉在多重RVA程序中,淀粉胶体反复形成并且溶解。添加油脂后的玉米淀粉的黏度曲线的变化是复杂的,由淀粉和油脂之间的相互作用引起,油脂的水溶性以及淀粉颗粒与蛋白质的关系影响着它们的相互反应。     

荸荠淀粉的特性研究

荸荠淀粉是从荸荠中提取的，本文通过与马铃薯淀粉和玉米淀粉相比较，用显微镜、偏光显微镜、凝胶色谱等方法，研究了荸荠淀粉的颗粒形状和大小以及它的化学组成和淀粉分子分子量的分布，并测定了荸荠淀粉的糊化温度和成糊后的透明度和凝沉性。结果表明：荸荠淀粉的特性与玉米淀粉和马铃薯淀粉的特性有明显的不同。     

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。      

大米淀粉的糊化特性研究

采用快速黏度分析仪(RVA)对不同大米原淀粉的糊化特性和不同取代度的淀粉磷酸酯的糊化特性进行了测定和比较研究。RVA测试结果表明,大米原淀粉中的直链淀粉含量、大米淀粉磷酸酯中的取代度都对其黏度特性产生很大的影响。     

抗性淀粉黏度特性的研究

采用快速黏度分析仪（RVA）对不同原淀粉及各抗性淀粉样品的黏度特性进行了测试。RVA测试结果表明：马铃薯RS样品的黏度特征值远远高于玉米RS、小麦RS产品。随着RS含量的增加，玉米RS、小麦RS和马铃薯RS样品的黏度都随之降低。     

抗性淀粉糊化特性的研究

采用差示扫描量热分析技术(DSC)对不同原淀粉及各抗性淀粉样品的糊化温度及热焓值进行了测试.DSC扫描曲线表明:抗性淀粉的DSC吸热曲线完全不同于原淀粉的吸热曲线,原淀粉只在70℃左右有一个较小的吸热峰,而抗性淀粉在150℃左右有一个较大的吸热峰,热焓值在30J/g左右;由不同来源淀粉制成的抗性淀粉样品之间其糊化特性没有显著差别.     

黄原胶对玉米淀粉糊化性能的影响

将黄原胶引入到淀粉浆料中,采用快速黏度分析法(RVA)研究了黄原胶的加入对玉米淀粉糊化性能和浆液表观黏度的影响,讨论了黄原胶与玉米淀粉分子之间的相互作用.结果表明:黄原胶可促进淀粉糊化,降低淀粉的糊化温度,缩短糊化时间;随着黄原胶质量分数的增加,淀粉的糊化峰值黏度增加,表现了2种高分子的相互作用;黏度衰减值随黄原胶增加...     

不同筋力小麦品种的搅拌值及其它淀粉糊化特性指标

以5个小麦品种为材料，利用快速粘度分析仪（RVA）研究了不同筋力品种间搅拌值的差异及搅拌值与其它淀粉糊化特性指标的关系。结果表明，不同品种间搅拌值有一定差异，酶浓度对搅拌值有显著影响。搅拌值与面团筋力无一致性，与糊化温度、糊化时间相关不显著，但是与高峰粘度、低谷粘度、粘度破损值、最终粘度以及回冷值等5项淀粉糊化指标显著正相关。同时求出了这5项淀粉糊化指标依搅拌值变化的回归方程。     

RVA日本大米品质分析法研究陈化对大米糊化特性的影响

快速黏度仪广泛应用于大米淀粉糊化特性的研究。对于质量相近的大米试样,RVA日本大米糊化特性评价法具有更好的优势。本文应用该方法将粳米、籼米及糯米在4、25和36℃下分别贮藏0、1、3和6月后通过快速黏度仪研究其糊化特性。在贮藏过程中大米发生代谢活动,加上脱支酶等引起的酶促反应,使其直链淀粉含量增加而支链淀粉含量减少,从而改变了直链淀粉/支链淀粉比例,因此,在加热-保持-冷却测试过程中反映出的峰值黏度、保持黏度、衰减值、最终黏度及回生值出现增加,同时,由于陈化后水分子进入淀粉颗粒所需能量减少使得糊化温度与峰值时间有所降低。另外,由于陈化使大米组织结构发生变化及大米淀粉微晶束产生改变等物理过程,加上不同种类大米的蛋白质及淀粉等组分受陈化温度与陈化时间的影响不同,使其淀粉糊化特性上的各个特性指标表现出明显的时间与温度依赖性。     

荸荠淀粉糊流变性质的研究

为有效开发利用荸荠淀粉,研究不同浓度的淀粉、食盐、蔗糖、黄原胶、卡拉胶以及瓜尔豆胶对荸荠淀粉糊动态及静态流变特性的影响,结果表明:荸荠淀粉糊是典型的剪切稀化的非牛顿型流体,荸荠淀粉浓度的改变以及食盐、蔗糖、黄原胶、卡拉胶和瓜尔豆胶的添加都对此性质不产生影响。表观黏度与剪切速率呈负相关。淀粉浓度越高,体系的储存模量(G′)、损耗模量(G″)越大,但损耗角正切值(tanδ)越小;食盐可提高体系的G′、G″和tanδ;高浓度的蔗糖使体系的G′、G″增大,但蔗糖的加入却使体系的tanδ降低;高浓度的黄原胶、卡拉胶和瓜尔豆胶3种亲水性胶体可提高体系的G′、G″和tanδ。     

不同筋力小麦品种的搅拌值及其它淀粉糊化特性指标_注

以 5个小麦品种为材料 ,利用快速粘度分析仪 (RVA)研究了不同筋力品种间搅拌值的差异及搅拌值与其它淀粉糊化特性指标的关系。结果表明 ,不同品种间搅拌值有一定差异 ,酶浓度对搅拌值有显著影响。搅拌值与面团筋力无一致性 ,与糊化温度、糊化时间相关不显著 ,但是与高峰粘度、低谷粘度、粘度破损值、最终粘度以及回冷值等 5项淀粉糊化指标显著正相关。同时求出了这 5项淀粉糊化指标依搅拌值变化的回归方程。     

响应面法分析球磨处理对玉米淀粉成糊温度和峰值黏度的影响

研究了经球磨处理后的玉米淀粉的成糊温度和峰值黏度。通过单因素试验和响应面法分析研究了球磨淀粉量,球磨转速和球磨时间对玉米淀粉成糊温度和峰值黏度的影响。结果表明:回归模型能很好地反映各因素水平与成糊温度和峰值黏度之间的关系;淀粉的成糊温度和峰值黏度随淀粉量的增加而升高,随球磨速度的增加和球磨时间的增长而下降;三因素对成糊温度的影响顺序为淀粉量>转速>球磨时间;三因素对峰值黏度的影响顺序为淀粉量>球磨时间>转速。结晶性研究和粒度分布结果表明,球磨后淀粉的结晶性下降,平均粒径上升,成糊温度和峰值黏度的变化是因为球磨改变了淀粉的结晶性及淀粉分子结构。     

小米淀粉与玉米淀粉糊性质比较研究

对小米淀粉和玉米淀粉糊性质进行较详细比较研究,包括透明度、冻融稳定性、凝沉性、膨胀力、酸解、酶解,和介质对糊粘度性质影响。结果表明,小米淀粉与玉米淀粉相比,糊的凝胶稳定性好、持水力强、膨胀力高、糊化温度高、热焓变值大、但透明度较差、冻融稳定性不佳、热稳定性差;且氯化钠及糖溶液对小米淀粉糊粘度性质影响较大。     

纤维素纳米晶体对甘薯淀粉糊化特性和流变特性的影响

采用快速黏度分析仪以及流变仪分析纤维素纳米晶体对甘薯淀粉短期回生的影响。结果表明:随着0.03、0.06、0.09、0.12、0.15 g的纤维素纳米晶体添加到1.5 g甘薯淀粉中,其回生值明显低于纯淀粉。静态剪切流变测试结果表明,复合体系符合幂定律模型,是一种假塑性流体,剪切应力随着纤维素纳米晶体添加量增加而呈现降低趋势,稠度系数K减少,流体指数n增大。动态黏弹性测试结果表明,纤维素纳米晶体增强了体系的流体性。纤维素纳米晶体是一种有前景的淀粉短期回生抑制剂。     

Pasting Properties of Ohmically Heated Rice Starch and Rice Flours

ABSTRACT:  Pasting characteristics were examined for conventionally or ohmically heated rice starch and rice flours. Brown rice flour showed the greatest cooking stability and least retrogradation potential. Brown rice flour also showed the greatest pasting temperature and lowest peak viscosity, whereas commercial starch had the lowest pasting temperature. Nonstarch components of the brown rice flour, such as fat and protein, may have acted as stabilizers delaying water access into the granules and reducing swelling of the starch. Ohmic heating reduced pasting temperature for commercial rice starch, resulting in a starch that swelled faster. Furthermore, ohmic heating produced better cooking stability in white rice flour 1 and 2 than in the native sample, and caused white rice flour 2 to have less potential for retrogradation than the conventionally heated sample. At lower electric field strength (20 V/cm), ohmic heating resulted in the greatest cooking stable starches compared to higher voltages (40 and 70 V/cm) because more starch granules were disrupted from a longer cooking time, so there were fewer intact granules for pasting. Ohmic heating has been shown to alter rice starch and flour pasting characteristics with an added influence of lipids, proteins, and amylose contents.     

Changes in Starch Pasting Properties Due to Sugars and Emulsifiers as Determined by Viscosity Measurement

The effects of sugars, emulsifiers, and their interactions on starch pasting properties were determined by the Rapid Visco-Analyser (RVA). Solutions of 50% sugars in water were used. The disaccharides, sucrose and lactose, delayed pasting more than did the monosaccharide, dextrose. Sugars’effects on starch pasting delay and on starch paste consistency varied with the starch. Addition of the same emulsifier (1%) to different starches did not result in the same change in paste consistency in the presence of high amounts of sugar. Both sucrose ester F-160 (SE) and polysorbate 60 (PS) reduced the hot paste consistency of starch-sugar mixtures, with SE having a greater effect than PS.     

Pasting Properties of Potato Starch and Waxy Maize Starch Mixtures

The pasting viscosity, morphological properties, and swelling properties of potato starch and waxy maize starch mixtures at different ratios were investigated. Pasting analysis of the starch mixtures (7% solids in water, w/w) using a Rapid Visco Analyser showed linear changes in peak viscosity and pasting temperature according to the mixing ratios of both starches, but not in breakdown and setback. The pasting profile revealed that the starches rendered mutual effects during pasting, more significantly when the amounts of potato and waxy maize starches were similar. The volume fraction of swollen granules and the presence of amylose appeared to be important parameters in the mutual effects of both starched during pasting. Under a light microscope, the swelling of potato starch granules was delayed by the presence of waxy maize starch. Overall results indicate that new pasting properties can be generated by mixing starches of different botanical sources.     

Using Ozonation and Amino Acids to Change Pasting Properties of Rice Starch

ABSTRACT:  In this study, the effects of ozonation and the addition of amino acids on rice starches were determined in terms of pasting properties using a rapid visco-analyzer. Results from viscosity analysis showed that 30-min ozone treatment on commercial rice starch exhibited the greatest swelling extent among the treatments and least retrogradation tendency. The control pure oxygen treated sample had the best cooking stability. The addition of lysine (6%) to 30-min ozonated commercial rice starch significantly reduced peak viscosity (PV), minimum viscosity (MV), and final viscosity (FV) by 918, 1024, and 1023 cP, respectively. Moreover, it decreased Ptime, resulting in the faster swelling upon heating and less rigid gel formation upon cooling. Furthermore, the presence of lysine in 30-min ozonated starch isolate (WSI) also significantly reduced PV, MV, FV, pasting time, and total setback (TSB) and produced starch gel with the best cooking stability and the least retrogradation tendency. Ozonated starch exhibited similar pasting properties to those from oxidized starches treated with low concentrations of chemical oxidizing agents. The combination of lysine with ozonation resulted in pasting properties similar to starches treated with high levels of chemical oxidizing agents. The ozonated starch could be used as a thickening agent, whereas ozonated starch with lysine might be an alternative for a highly chemically oxidized starch. Therefore, ozonation alone or the combination of ozonation and addition of lysine might be used to develop new starch ingredients with various functionalities without using typical chemical modifications.