Assessment of starch gelatinization by ultrasonic and calorimetric techniques

The process of starch thermal gelatinization can be studied and monitored by employing both invasive and non-invasive techniques. In this paper, the ultrasound technique is compared with differential scanning calorimetry (DSC), a more traditional procedure. DSC is a convenient way to fulfill this objective although it is, by nature, an invasive, discontinuous and off-line technique. Among the main features of this ultrasound technique are its real-time performance and its intrinsic non-invasive character: a sample cell fitted with two piezoelectric ceramics as emitter and receptor, is used. A pulse generator and an oscilloscope are used to generate the emitted signal and to analyze the response, respectively. The procedure is tested using aqueous corn starch suspensions at two concentrations. The temperature is increased through the gelatinization interval, and the changes in ultrasound amplitude are recorded. Experimental data are in good agreement with those obtained by DSC. The progress of the gelatinization process can be followed by this method and the possibility of its use for on-line processes is considered.     

Kinetics of cowpea starch gelatinization and modeling of starch gelatinization during steaming of intact cowpea seed

Steaming of cowpea seeds prevents weevil infestation during storage. Physicochemical changes such as starch gelatinization from steaming may lead to seed resistance to weevil penetration and digestion. A kinetics of starch gelatinization was constructed and incorporated in a heat and mass transfer model to quantitatively investigate starch gelatinization in intact seeds during steaming. The outer layers of steamed seeds (0.5 mm thick) were removed by a specially designed grinding device to measure degree of starch gelatinization (DG). The predicted DG in the outermost layer of seeds was found to be in good agreement with experimental data. The average relative error for DG was 14.6%.     

淀粉的不同糊化方法

综述淀粉的不同糊化方法,对目前常用的糊化方法和新型化学糊化方法分别进行概述,阐述了这些方法的原理和应用,探讨将新型化学糊化方法应用于淀粉颗粒结构研究的途径.     

角质玉米淀粉糊化的研究

以角质玉米粉为主要原料,在不同的角质玉米粒子半径下,研究糊化时间对玉米浆黏度、固形物含量、pH的影响,确定糊化玉米粉的最佳工艺参数。其最佳工艺参数为均质压力为15MPa,在90℃下糊化30min。     

淀粉糊化及其检测方法

淀粉糊在食品工业具有重要应用价值,淀粉糊性质直接影响食品品质。该文介绍淀粉糊化特性及其检测方法,详述各种检测方法在淀粉糊中应用实例,并指出其中优缺点;提出今后淀粉糊检测方法发展方向,为淀粉糊在食品工业广泛应用奠定基础。     

啤酒生产中玉米淀粉辅料糊化工艺改进

探讨了一种新的玉米淀粉辅料加工工艺，即在糊化锅内将淀粉直接糊化、糖化制成糖浆，然后直接导入煮沸锅，与麦汁一同煮沸、发酵。新工艺与传统工艺比较。大大缩短了麦汁过滤时间，制成的糖泉与麦汁成分相近，具有较传统工艺更高的麦芽糖．同时淀粉糊化后不需煮沸，节约了蒸汽能源。     

高直链交联变性淀粉结构及糊化性质的研究

本文采用OlympusVanoxBHS-2型多功能光学显微镜对高链及其交联变性淀粉的结构及糊化温度与pH值之间的关系进行了研究,对促进变性淀粉在生产中的应用有重要意义。     

小麦淀粉生产过程工艺因素对淀粉糊化特性的影响

研究小麦淀粉生产工艺因素中乳酸、焦亚硫酸钠、α-淀粉酶以及提取工艺对淀粉糊化特性的影响。结果表明,小麦淀粉中乳酸含量达到69.2 mg/kg,峰值黏度、回生值分别降低了42.1%和100%。焦亚硫酸钠对小麦淀粉糊化特性的影响和添加乳酸相似,含量达到3.3 mg/kg时,峰值黏度、回生值分别下降了18.0%和18.9%。小麦淀粉中α-淀粉酶活性达到123.1 U/100mL时,峰值黏度、回生值分别降低了45.7%和97.0%。提取工艺中旋流法和卧螺法对小麦淀粉糊化特性影响差异不明显,但马丁法小麦淀粉谷值黏度、最终黏度明显低于旋流法和卧螺法淀粉。通过对小麦淀粉生产工艺中各因素研究表明,减少杂菌感染产酸,适量添加焦亚硫酸钠以及尽量避免使用α-淀粉酶活性高的新小麦或发芽小麦制粉,有利于解决小麦淀粉在应用中出现的粘连、凝胶强度不够等问题。     

莲藕淀粉糊化温度的测定

对莲藕糊化温度的三种测定方法展开比较,得出偏光十字消失法测得莲藕淀粉的糊化温度为63.8～71.8℃,差示扫描量热分析法(DSC)测得糊化温度为63.5～74.7℃,动态流变仪法测得糊化温度为60.1～66.2℃。得出结论:在一般的实验室里,品种相同的情况下,应用偏光十字消失法是较为准确且经济的测定方法;如果条件允许,动态流变仪法是相对精确的方法。     

Effect of honey types and concentration on starch gelatinization

The complex and variable composition of honey, depending on source, season and processing, means different honey samples could cause variation in the characteristics of the finished product. The objective of this study was to determine how the minor components present in honey affect starch gelatinization. A Rapid Visco Analyser was used to measure changes in viscosity when unmodified maize starch was gelatinized in a honey or model sugar solution. When honey was compared to equivalent blends of sugars, there was an increase in starch viscosity with increasing levels of addition. However, at the same level, honey gave a lower viscosity than the blends of sugars. Honeys from different sources (differing in pH and amylase activity) show a varied effect on starch gelatinization, with starch viscosity increasing with addition level for six of the honeys, but decreasing with increasing addition level for two honey samples. Varying the pH also produced variation in starch gelatinization patterns between honey types. Between pH 3.0 and 4.0, starch viscosity was similar for all four honey types studied, while above this pH there were differences between all honey types. As expected, starch viscosity decreased as the solution pH neared the optimum for honey amylase activity (pH 5.3-5.6), though it did not increase as the pH moved away from the honey amylase activity optimum. Differences between honey samples, and between honey and a model sugar mixture, in their effect on starch gelatinization was attributed to honey amylase activity and the composition and concentration of minor organic compounds present.     

辐照淀粉与聚丙烯酰胺共煮糊化特性

淀粉经γ-射线辐照后将产生过氧化物和自由基,在其与聚丙烯酰胺共煮糊化的产物中,通过红外光谱分析检测出接枝反应的产物,这种接枝反应可能与过氧化物的分解以及聚丙烯酰胺的霍夫曼反应有关。同时,不同的糊化条件能使浆液的特征粘度发生变化,高压煮浆使浆液具有更高的粘度,但是相同糊化条件下浆液的粘度性能稳定。     

苦荞淀粉糊化性质的研究

通过使用DV-T2黏度温控一体机测定苦荞淀粉在不同溶剂中黏度的变化曲线.结果 表明,苦荞生粉的热稳定性、凝胶性较早餐粉苦荞强,更易回生;以硬度高的水为溶剂时苦荞淀粉的热稳定性较好,凝胶性较弱,不易回生;以柠檬酸溶液或食盐溶液为溶剂时,苦荞淀粉的热稳定性随浓度的升高而增强,凝胶性随浓度的升高而减弱,不易回生;以蔗糖溶液为...     

电导率法淀粉糊化温度测定及其影响因素的研究

改进通电加热淀粉悬浮液过程中电导率的测定装置,有效地防止淀粉悬浮液的沉淀及水分散失,提高测量精度,使之可用于淀粉糊化温度的测定,并将结果与差示扫描热量仪fDSCl测量结果进行了比较.并进一步研究淀粉浓度、NaCl浓度和电压对淀粉悬浮液的电导率、加热速率及所测得糊化温度的影响.结果表明:通电加热淀粉悬浮液时,随NaCl浓度的增加,所测得的糊化温度逐渐增大.随淀粉浓度的升高,所测得的糊化温度逐渐降低.随着电压的增大,淀粉悬浮液的电导率和加热速率也随之增大.改进后的装置可准确测定淀粉的糊化温度.与DSC结果相近.     

Effects of some anionic polysaccharides on the gelatinization and retrogradation behaviors of wheat starch: Soybean-soluble polysaccharide and gum arabic

Gelatinization and retrogradation behaviors of wheat starch were investigated in an aqueous system in the presence or absence of some anionic polysaccharides, soybean-soluble polysaccharide (SSPS), and gum arabic (GA). Weight-average molecular weight was almost equivalent between SSPS and GA, while z-average root-mean-square radius of gyration of GA was ca. twice as large as that of SSPS. The addition of each polysaccharide (0.1–1 w/v%) decreased the peak viscosity of the composite system (starch concentration: 5% or 13%) during gelatinization, and this effect of SSPS was greater than that of GA at the higher starch concentration. It also shifted the onset of viscosity increase to lower temperatures at the higher starch concentration, but no difference was seen in this effect between SSPS and GA. The addition of each polysaccharide (0.1–1%) decreased the amount of amylose leached during gelatinization, and this effect of SSPS was generally greater than that of GA. It hardly altered, on the other hand, the average particle diameter of the starch granules after gelatinization. “Starch ghosts” were less frequently observed microscopically in the presence of each polysaccharide, which appeared to exist around the surface of the starch granules to inhibit amylose leaching. The addition of each polysaccharide (0.5%) increased the rate constants, representing short-term (24 h) retrogradation of starch (5%). It also decreased the saturated dynamic storage modulus of the composite system after storage at 4 °C for 24 h, and this effect of SSPS was greater than that of GA with larger amount of syneresis generated. The results were discussed mainly in relation to the phase arrangement between starch components and each polysaccharide.     

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.     

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.     

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。