普鲁兰多糖对大米淀粉糊化和老化特性的影响

以实验室自提高直链大米淀粉为原料,以10%的海藻糖为参照,采用差示扫描量热仪(DSC)和快速黏度分析仪(RVA)分别分析了不同添加量的普鲁兰多糖对大米淀粉的热力学性质和黏度特性的影响,并用扫描电子显微镜(SEM)对在4℃条件下贮存14d的大米糊化淀粉的颗粒形貌进行观察。结果表明,普鲁兰多糖的添加会不同程度降低高直链大米淀粉的老化焓值、峰黏度、谷黏度、终黏度、回生值,提高大米淀粉的糊化温度,当添加15%普鲁兰多糖时能较好的延缓大米淀粉的老化,RVA所测得的回生值从2463.67cP降低到471.33cP;当添加25%普鲁兰多糖时,对淀粉的老化抑制效果最好。      

普鲁兰多糖对绿豆淀粉功能特性的影响

以资源丰富的绿豆淀粉为基材,按照不同比例与普鲁兰多糖共混,对混合物的功能特性进行了研究。结果表明:普鲁兰多糖可以降低绿豆淀粉的峰黏度、谷黏度、终黏度、稀懈值和回凝值,并且在一定范围内,这种变化随着普鲁兰多糖质量分数的增加而增大。另外,普鲁兰多糖的添加提高了绿豆淀粉的糊化温度,使其糊化受到抑制作用,且当普鲁兰多糖与绿豆淀粉的质量比达到2∶5时,这种抑制作用开始达到极显著水平。少量添加普鲁兰多糖后,绿豆淀粉老化的焓变值大大降低,但当普鲁兰多糖与绿豆淀粉的比例大于1∶6时这种抑制作用变缓。普鲁兰多糖可以增强绿豆淀粉的硬度、黏着性、弹性和胶凝性,而逐渐减小其黏聚性。     

普鲁兰多糖对籼米粉凝胶及老化特性的影响

探究不同添加量的普鲁兰多糖(0%、2%、4%、6%、8%)对籼米粉糊化特性、流变特性、凝胶质构以及微观结构的影响。结果表明,普鲁兰多糖的添加使米粉的糊化特性、流变特性、凝胶质构和微观结构发生显著变化。随着普鲁兰多糖添加量的增加,混合粉的峰值黏度、最低黏度、崩解值、回生值、弹性模量、黏性模量均逐渐降低,糊化温度略有升高,表明普鲁兰多糖抑制了大米淀粉的糊化;X-射线衍射的分析表明普鲁兰多糖的添加降低了淀粉的重结晶度,抑制了淀粉老化;普鲁兰多糖添加后的凝胶呈现出多孔状结构,表明淀粉连续性的凝胶结构被破坏,从而导致凝胶的硬度、弹性、黏聚性、胶着度、咀嚼性逐渐降低。     

普鲁兰酶对甘薯淀粉糊化回生特性影响研究

采用普鲁兰酶对甘薯淀粉进行酶解脱支处理,通过单因素试验分别考察酶解时间、酶解pH、酶解温度、酶添加量对淀粉回生值以及直链淀粉含量的影响。并根据单因素试验结果设计正交试验,结果表明:最佳酶解条件为酶解时间15h,酶解pH 4.5,酶解温度55℃,酶添加量48ASPU/g。该条件下酶解淀粉的回生值达到最高为1 925cp,直链淀粉含量达到最高为25.21%。通过与原淀粉比较得出:淀粉凝胶强度、破裂强度都显著增大(P0.05),峰值黏度、谷值黏度和最终黏度均有降低,衰减值增大。     

大豆多糖对大米淀粉糊化及凝胶特性的影响

以大米淀粉为材料,研究了大豆多糖对淀粉糊化及凝胶特性的作用.通过布拉班德黏度计,DSC差示量热扫描和质构仪等分析手段,研究分别添加相当于淀粉干基质量分数1.0%、2.5%、5.0%的大豆多糖的影响.结果表明,大豆多糖能有效降低大米淀粉黏度,改善其凝胶品质,且添加量越大,效果越明显,对淀粉基食品的改良有重大意义.     

普鲁兰多糖对挤压流延法制备淀粉膜性能的影响

对普鲁兰多糖改善淀粉基可食性膜的性能进行研究,并用光学显微镜对膜表面进行观察。结果表明:添加普鲁兰多糖后有效的改善了淀粉膜的拉伸性能;随着普鲁兰多糖添加量的增加,降低了淀粉膜的水溶解时间和O2透过率;当普鲁兰多糖添加量在5%~9%时,淀粉膜具有较低的透湿性,且淀粉膜的白度较高,黄色值较低。光学显微分析膜表面,当普鲁兰多糖添加量为9%时,普鲁兰多糖与淀粉能较好的融合。综合膜的各项性能得出,普鲁兰多糖的添加量不宜超过9%。     

动态高压微射流改性可溶性大豆多糖对大米淀粉老化特性的影响

采用动态高压微射流（dynamic high pressure microfluidization,DHPM）分别在80、120、170 MPa条件下对可溶性大豆多糖（soluble soybean polysaccharides,SSPS）改性,通过扫描电镜（scanning electron microscope,SEM）和傅里叶红外光谱（fourier transform infrared spectroscopy,FTIR）比较改性前后SSPS表面形态和分子结构的变化。结果表明：改性后SSPS的主体结构基本未发生变化,只是样品内部氢键作用减弱,有序性降低;外观形态发生破碎断裂现象,形成多孔结构,整体结构变得松散。然后通过快速黏度分析仪（rapid visco analyser,RVA）、差示扫描量热法（differential scanning calorimetry,DSC）、FTIR手段研究改性后可溶性大豆多糖（modified solublesoybean polysaccharides,MSSPS）对大米淀粉（rice starch,RS）老化特性的影响。添加MSSPS组与SSPS组比较,RS糊化峰值黏度、最终黏度、回复值、糊化焓值以及FTIR图谱1 047、1 022 cm-1处的峰高比值均显著降低（P＜0.05）。结果表明：添加MSSPS后,RS的老化程度显著降低（P＜0.05）,且改性压强增大,MSSPS抑制老化的效果显著增强（P＜0.05）。     

芒果皮粉对淀粉糊化与老化特性的影响

采用布拉班德黏度仪、差示扫描量热仪等测定芒果皮粉的添加对玉米淀粉和大米淀粉黏度、热特性、透光率、沉降率、凝胶硬度与色泽的影响。结果表明,随芒果皮粉添加量(0%~15%)的增加,2种淀粉的起糊温度逐渐降低,玉米淀粉糊峰值黏度在添加15%芒果皮粉时显著升高,崩解值增大;大米淀粉糊峰值黏度呈降低趋势,崩解值先降低后升高,2种淀粉回生值都显著降低。芒果皮粉的添加显著降低了2种淀粉的糊化和老化焓值及贮藏中透光率与沉降率的下降程度,减小玉米淀粉凝胶的硬度,降低了2种淀粉凝胶色泽的变化程度。说明芒果皮粉的添加影响淀粉的糊化特性,且影响趋势随淀粉品种不同而异,但能有效抑制2种淀粉的老化。     

普鲁兰多糖在土豆淀粉废水中的发酵条件研究

普鲁兰多糖是一种具有重要应用价值的微生物胞外多糖。淀粉废水是加工淀粉过程中不可避免的一种产物,成分复杂,营养丰富。利用淀粉废水作为碳源制得普鲁兰多糖,不仅使多糖的生产成本降低,变废为宝,还会减少环境污染。应用改进的非水解法进行发酵,通过单因素实验确定了菌种W2003在土豆淀粉废水中发酵的最佳条件为:28℃,转速为150r/min,初始pH=6.5,120h。     

水分含量对燕麦淀粉糊化老化特性影响的研究

本研究采用扫描电镜法、X-射线衍射法和差示扫描量热法(DSC),从淀粉的颗粒形貌特性、晶体结构特性和热力学特性的变化,来研究水分含量对燕麦淀粉糊化老化特性的影响。结果表明:燕麦淀粉的X-衍射图谱为A型,含水量较低(70%)时,老化后的燕麦淀粉凝胶质地坚硬表面空隙较大,衍射峰相对强度大,含水量较高(90%)时,凝胶表面质地均匀,衍射峰的相对强度较弱。燕麦淀粉重结晶晶体融化的起始温度(To)、顶点温度(Tp)、终止温度(Tc)和融化热焓值(ΔH),以及晶体生长速率均随含水量增加而降低,说明增加含水量可延缓燕麦淀粉老化;随着贮藏时间的延长焓值(ΔH)有所增加,说明燕麦淀粉老化度随贮藏时间延长而增加;同时,含水量在60%~90%时,燕麦淀粉重结晶的成核方式为一次成核。说明燕麦蒸煮类食品的老化度随着贮藏时间的延长而增加,但适当增加含水量可延缓贮藏过程中燕麦淀粉的老化现象。     

Influence of xyloglucan on gelatinization and retrogradation of tapioca starch

Dynamic and steady shear rheometry and differential scanning calorimetry (DSC) were used to investigate effects of xyloglucan (XG) on gelatinization and retrogradation of tapioca starch (TS). The viscosity of TS/XG pastes immediately after gelatinization increased with increasing XG content at the total polysaccharide concentration of 3.5%. Gelatinized TS alone showed pseudoplastic flow at low shear rates and dilatant behavior at higher shear rates (about >1 s⁻¹), while mixtures with XG did not show dilatancy. Mechanical spectra of TS pastes containing XG were more liquid-like than those of TS pastes without XG. XG provides shear stability to the TS during storage. Increases in dynamic moduli during storage at 5 °C were suppressed in the presence of XG. In contrast, the retrogradation ratio determined based on DSC increased more rapidly in the presence of XG. These results suggest that XG forms a continuous liquid phase in a mixture to impart better mechanical stability during storage but to accelerate re-ordering of starch polysaccharides by effectively reducing the amount of water available for starch.     

Effects of phosphorus contents on the gelatinization and retrogradation of potato starch

ABSTRACT:  Effects of phosphorus content (510 to 987 ppm) on the gelatinization and retrogradation of 6 potato cultivars (Benimaru, Hokkaikogane, Irish Cobbler, Konafubuki, Sakurafubuki, and Touya) were studied. Pasting properties were analyzed by RVA, thermal properties by DSC, and mechanical properties of the starch gels by TA. Phosphorus was positively correlated with swelling power ( r = 0.84) and negatively correlated with solubility ( r = 0.83). Phosphorus content showed significant effect on certain pasting properties of potato starch such as peak viscosity, breakdown, and setback. Phosphorus content showed a significant positive correlation with peak viscosity ( r = 0.95) and breakdown ( r = 0.90). Increasing concentration of phosphorus tends to decrease the setback. Phosphorus content had no influence on thermal properties and mechanical properties of potato starch gel.     

Effect of low molecular weight dextrins on gelatinization and retrogradation of starch

!-Amylases, usually added to bread recipes as anti-firming agents, are known to produce low molecular weight dextrins by starch hydrolysis. The influence of these compounds on the gelatinization and retrogradation of starch was studied by differential scanning calorimetry. Adding oligosaccharides to starch caused a delay in gelatinization, although its extent was not quantified. However, oligosaccharides of degrees of polymerization (DP) 3-5 reduced the enthalpy of the retrogradation endotherm, shown as the staling endotherm. The addition of gluten to starch and starch/oligosaccharide mixtures had no effect on the gelatinization and retrogradation of starch. The retrogradation of starch in dough samples was also analysed, after 'baking' in the calorimeter, to obtain additional information about starch retrogradation during storage. Oligosaccharides of DP 3-5 also reduced the enthalpy of the retrogradation endotherm. This work provides evidence that oligosaccharides influence starch changes during the baking and storage of bread. These effects could be considered as the mechanism by which the bacterial !-amylase reduces starch retrogradation and acts as an anti-firming agent.     

小杂粮淀粉糊化及回生研究进展

荞麦、燕麦、糜子是特色小杂粮,但由于对其糊化特性和老化特性影响因素缺乏系统的研究,对其开发依旧停留在初级加工的水平,制约了甘肃特色杂粮加工产业的发展。该文从淀粉自身特性、外源物质添加和加工方式三个方面综述了近年来促进粉糊化与抑制淀粉回生新技术,为特色小杂粮的高质化利用提供理论支持。     

糯米淀粉凝胶的老化特性分析

以传统加热糊化法制备的糯米淀粉凝胶为研究对象,通过测定凝胶老化过程中的9项品质特性指标,分析糯米淀粉凝胶老化过程中各指标的变化规律及其相关性。利用主成分分析法确定影响糯米淀粉凝胶老化的主要因素及时间拐点。结果表明,随着储藏时间的延长,糯米淀粉凝胶硬度、胶着性呈逐渐增加的趋势,回复性、弹性、水分、持水性、碘蓝值和酶解力呈递减的趋势,除碘蓝值外的其他理化指标均与质构指标有一定的相关性。主成分分析表明,第7 d是糯米淀粉凝胶老化过程中质构品质变化的拐点,硬度和胶着性可以作为糯米淀粉凝胶评价体系的主要指标。     

羟丙基交联木薯淀粉对籼米淀粉老化特性的影响

以籼米淀粉为原料,考察添加不同比例的羟丙基交联木薯淀粉（HP-CLTS）,对籼米淀粉粘度特性以及样品糊化后贮藏过程中持水力、质构特性、外貌形态和红外光谱的影响,发现随HP-CLTS添加量增加,籼米淀粉糊化温度、衰减值逐渐降低,而峰值粘度、热糊粘度、崩解值、终值粘度呈升高趋势。样品贮存过程中持水力增强而凝胶硬度显著下降（p<0.05）;添加HP-CLTS后混合淀粉糊化凝胶4℃老化7d的冻干样品,扫描电镜观察显示添加HP-CLTS的淀粉凝胶具有比纯籼米淀粉更疏松多孔的网络空腔结构,从微观结构上证明了HP-CLTS具有高的持水能力,能老化过程中凝胶水分损失;凝胶傅里叶红外光谱显示随HP-CLTS添加量增加1047cm-1处吸收峰减弱,而1022cm-1处的峰强度增强,说明HP-CLTS能够抑制籼米淀粉老化结晶。结果表明添加一定量HP-CLTS能有效抑制籼米淀粉老化。      

聚葡萄糖对大米淀粉凝胶老化特性的影响

为探究聚葡萄糖(PD)对大米淀粉(RS)凝胶老化特性的影响,利用快速黏度分析仪(RVA)、差示扫描量热分析(DSC)、X-射线衍射分析(XRD)和扫描电子显微镜(SEM)研究聚葡萄糖对大米淀粉糊化黏度特性、热特性、晶体结构和微观结构的影响。结果表明,随着聚葡萄糖添加量的增大,大米淀粉糊化的峰值黏度、崩解值和回生值均显著下降(p<0.05);但是糊化温度升高,大米淀粉的糊化焓值和老化焓值均显著降低(p<0.05),大米淀粉凝胶的相对结晶度从14.09%降到8.61%。SEM结果表明添加聚葡萄糖后,大米淀粉凝胶孔洞变小,表面更致密、光滑,说明聚葡萄糖可以抑制大米淀粉凝胶的重结晶,延缓大米淀粉凝胶的老化。