Effect of Mesona Blumes gum on physicochemical and sensory characteristics of rice extrudates

The aim of this study was to evaluate effects of Mesona Blumes gum (MBG) on some physical, chemical, sensory and antioxidant properties of rice extrudates. MBG was added to rice flour at 0%, 5%, 10%, 15% and 20% (w/w). The water solubility index (WSI) increased from 4.19% to 15.32% with MBG addition. Both water absorption index (WAI) and moisture retention (MR) reached maximum at 15% MBG. Bulk density (BD) was the highest at 5% (131.22 g cm^?3) and the lowest at 15% MBG (121.44 g cm^?3). Hardness was maximal at 5% (8.44 N mm^?2) and minimal at 15% MBG (5.98 N mm^?2). Expansion ratio (ER) and lightness (L*) decreased for all extruded products with MBG. MBG at 5% or 10% level could improve sensory characteristics of final products. The extract of extrudates at 15% MBG had the highest antioxidation ability among those extrudates. Thus, it was possible to produce a new palatable rice extrudate with MBG.     

微波辅助碱液提取仙草多糖

研究微波辅助碱液提取仙草多糖的工艺条件。考虑沸水浴时间、碱液浓度、料液比和微波处理时间4个因素对仙草粗多糖提取率的影响,通过单因素试验选择各因素较理想的4个水平,再通过正交试验优化工艺参数。结果表明：碱液浓度是提高仙草多糖提取率的最显著因素,其次是料液比,微波处理时间和沸水浴时间对提取率的影响相对较小。在微波功率400W条件下,碱液浓度0.125mol/L、微波时间90s、料液比1:35(mg/mL)、水浸提1h时仙草粗多糖提取率最高,达到43.84%。     

香豆胶与玉米淀粉混合物流变特性的研究

为了研究不同质量分数（0%、2%、4%、6%、8%）的香豆胶对玉米淀粉糊化混合物剪切流变特性与动态黏弹性的影响,使用旋转流变仪,采用Herschel-Bulkley模型对剪切流变数据进行分析。测试结果为：香豆胶与玉米淀粉糊化混合物是假塑性流体。随着香豆胶质量分数的增加,混合物稠度系数K显著增加,下行线流体指数n显著降低,假塑性增强。动态黏弹性测定结果为：混合物贮能模量（G''）和损耗模量（G''）都随香豆胶质量分数增大而增大,损耗角正切tanδ＜1,说明香豆胶的添加增大了混合物的黏弹性。当香豆胶质量分数为8%时,混合物黏性最大,弹性最小,混合物具有更好的黏弹性。     

凉粉草多糖提取及纯化工艺的研究

研究Na2CO3浓度、料液比、提取时间对多糖提取率的影响,双氧水浓度和加入量对多糖脱色效果的影响,比较截留分子量为10K与50K中空纤维膜管对多糖超滤纯化的效果。结果发现,凉粉草多糖的最佳提取工艺为:碳酸钠溶液1.5%(M/V),料液比9/250(M/V),提取1.5h。在此条件下,测得凉粉草多糖的提取率为41.00%,总糖含量为3.495%;100mL料液中加入10%的双氧水20mL时脱色效果可达超滤工艺要求;截留分子量为10K的中空纤维膜管在超滤后多糖的保留率高于50K的。因此可选择截留分子量10K的中空纤维膜管对凉粉草多糖进行纯化。     

Rheological and physical characterization of film-forming solutions and edible films from tapioca starch/decolorized hsian-tsao leaf gum

Rheological properties of the film-forming solutions of tapioca starch/decolorized hsian-tsao leaf gum (dHG) as well as the structural properties and viscoelasticity of the resulting films were characterized as a function of dHG and glycerol concentrations. As compared to film-forming solutions with tapioca starch alone, the apparent viscosity, storage modulus and loss modulus of starch/dHG film-forming solutions increased, and tan δ decreased with increasing dHG. After casting of the film-forming solutions, all starch/dHG films showed relatively low opacity values. SEM and X-ray diffraction analysis revealed that all starch/dHG films exhibited homogeneous and highly amorphous structure. The extensional creep compliance of starch/dHG films increased with increasing glycerol concentration, implying weaker mechanical strength and higher mobility of polymer chains by the plasticizing effect of glycerol. However, addition of dHG pronouncedly increased the mechanical and elastic properties of tapioca starch films as evidenced by a decrease in extensional creep compliance and retardation time. Such results implied that dHG may possibly modify the network structure of tapioca starch film.     

凉粉草胶与不同淀粉混合体系糊化和质构性质的研究

凉粉草胶(MBG)与淀粉作用可以形成凝胶。为比较不同淀粉与MBG混合体系糊化和凝胶性质的差异,选取玉米等八种常见淀粉,利用Brabender糊化仪、质构仪、对MBG与不同淀粉混合体系的糊化和质构性质进行了研究。结果发现,MBG对谷类淀粉(大米、小麦、玉米)和豆类淀粉(绿豆、豌豆)的糊化性质的影响都比较显著,对薯类淀粉(木薯、马铃薯、甘薯)的不显著,但MBG与薯类淀粉混合体系的黏度远高于MBG与豆类和谷类淀粉的;MBG与大米淀粉形成的凝胶硬度最大,与马铃薯淀粉形成的凝胶硬度次之,与豌豆淀粉形成的凝胶硬度最小。淀粉与MBG之间相互作用的强弱可以从Brabender糊化曲线上的特征点值E-D来比较。     

瓜尔胶和黄原胶对马铃薯淀粉糊化特性影响的比较研究

将马铃薯淀粉分别与瓜尔胶和黄原胶以一定的比例复配,探讨两种胶体对马铃薯淀粉黏度、热稳定性、凝沉性、冻融稳定性和质构特性等糊化特性的影响。结果表明:瓜尔胶提高了淀粉糊的黏度和冻融稳定性,降低了淀粉糊的热稳定性、凝沉性、硬度、黏附性、胶黏性和咀嚼性;而黄原胶增加了淀粉糊的热稳定性和冻融稳定性,但降低了糊的黏度、凝沉性、硬度、黏附性、胶黏性和咀嚼性;且随着两种胶体含量的不同淀粉糊化特性也不同。      

魔芋胶和玉米淀粉混合物黏弹特性的研究

目的 研究魔芋胶对玉米淀粉黏弹特性的影响。方法 以玉米淀粉为原料, 加入不同比例的魔芋胶, 采用动态流变仪来研究魔芋胶玉米淀粉糊化混合物的黏弹特性。结果 Power-Low模型能够有效地表征魔芋胶玉米淀粉糊化混合物的流变性能。魔芋胶玉米淀粉糊化混合物为假塑性流体, 与单独的玉米淀粉糊相比, 随着魔芋胶的添加量增大, 糊化混合物黏稠性增大, 假塑性增强。随着频率的增大, G?和G?均增大, 损失正切值tan δ＜1, 说明魔芋胶的加入使得糊化混合物具有优越的黏弹性。结论 当魔芋胶/玉米淀粉质量比为0.4:0.8时, 糊化混合物弹性最小, 黏性最大, 糊化混合具有更好的协同增稠作用, 即糊化混合物流体流动特征显著。     

结冷胶对马铃薯淀粉回生特性的影响

向马铃薯淀粉中添加不同含量的结冷胶（0.4%、1.0%、2.0%、3.0%,以淀粉干基计）,采用差示扫描量热仪、X-射线衍射、全质构和凝沉体积测定方法,研究结冷胶对马铃薯淀粉的热特性、结晶度、凝沉性和质构特性的影响。结果表明:结冷胶在0.4%³.0%添加量下,显著提高了马铃薯淀粉回生焓值（p<0.05）;结冷胶在0.4%³.0%添加量下,冷藏7 d的样品相对结晶度由10.78%增加到13.91%。此外,结冷胶加速了马铃薯淀粉的凝沉,但在钙离子体系下提高了凝胶的稳定性。结冷胶改变了马铃薯淀粉的回生性质,为其成膜提供了理论依据。      

Rheological/textural properties of starch and crude hsian‐tsao leaf gum mixed systems

The Effects of hsian‐tsao leaf gum (HG) on the rheological/textural properties of non‐waxy starches were studied. Pronounced interactions between starch and HG were observed. The rheological properties, including pseudo‐gel viscosity in the rapid visco‐analyser test, storage and loss moduli in the dynamic rheological test, as well as firmness in the texture analyser test, of the mixed gels generally improved with increasing gum concentration to a certain level, then deteriorated with further increase in gum concentration. The critical gum concentration for the development of optimal rheological properties depended on the starch type and concentration. Within the concentration range studied, mixed systems with wheat starch could generally reach the highest pseudo‐gel viscosity, firmness, and storage modulus if the starch/HG ratio was appropriate, followed by those with corn and tapioca starch. Copyright © 2003 Society of Chemical Industry     

Physicochemical properties and sensory evaluation of Mesona Blumes gum/rice starch mixed gels as fat-substitutes in Chinese Cantonese-style sausage

Effect of Mesona Blumes gum (MBG)/rice starch mixed gels on the fat substitute of Chinese Cantonese-style sausage was investigated in this study, monitored with physicochemical properties and sensory evaluation analyses. Experimental results suggest that there were no significant differences among pH, yield, residual nitrite and TBARS of high-fat (28%), low-fat (18%) and fat-substituted (18%) sausages. The same fat content of low-fat and fat-substituted sausages would aid to compare their physicochemical properties more effectively. In addition, the emulsifying stability and water holding capacity of fat-substituted sausages were better than those of the other groups. During refrigerated storage (4 °C, 3 weeks), fat-substituted sausages reflected similar hardness, chewiness and shear force properties with those of high fat sausages and higher than those of low fat sausages. Furthermore, results of the sensory evaluation indicated that fat-substituted sausages showed superior total acceptability compared with low-fat one after a 2 week refrigerated storage, but was slightly less than that of high-fat one at the same condition. Therefore, MBG/rice starch gels can be effectively used as a fat substitute in Chinese Cantonese-style sausage allowing the manufacture of healthier sausages.     

Rheological properties of xanthan gum-gelatine spray-dried mixtures. Application in a custard-like formulation

 The effect of a spray-drying process on the rheological and textural properties of xanthan gum-gelatine dispersions was studied. Remarkable differences were found between co-dried samples and dispersion samples. Apparent viscosity and extrusion values were higher and shear-thinning behavior more pronounced than in non-dried samples. Also, stronger thickening and stabilizing properties were noticed. With regard to viscoelastic properties, an increase in the elastic component was observed. The new product was used in a standard confectioner's custard formulation and its properties were studied. When these samples were compared with a traditional custard made with starch, although enhanced rheological properties were recorded a similar visual appearance between samples was observed. Received: 27 March 2000     

Gellan gum/cassava starch mixtures in water systems and in milk systems

Cassava starch is an important ingredient in various foods. However, when processed, it develops some properties that are unsuitable for many industrial applications, such as unstable viscosity and excessive cohesiveness. To reduce those disadvantages, one alternative is a mixture of starch with hydrocolloids. The aim of this study was to evaluate the effect of 0:05, 0.1, 0.2, or 0.3% w/v gellan gum on the physical properties of pastes and gels of cassava starch in water and in milk systems. Differential scanning calorimetry (DSC), pasting properties, the texture profile, and the microstructure of gels were studied. The addition of gellan gum dispersions to the water system (WS) and the milk system (MS) gave rise to pastes with higher viscosity and, in the case of MS, with lower thermal and shear stability (higher breakdown). The addition of gellan gum had a greater textural effect on the MS, in which the addition of gellan at concentrations of 0.1 and 0.3% increased adhesiveness and decreased springiness of gels. Microscopy revealed a more uniform gel structure in the MS compared with the WS. Starch gelatinization temperatures were higher in MS than in WS.     

Preparation of resistant starch from starch–guar gum extrudates and their properties

Mixtures of starch, guar gum and citric acid were extruded at a temperature of 150 °C and screw speed of 180 rpm. Properties of the extrudates such as bulk density, expansion ratio, apparent viscosity and resistant starch content were measured with different concentrations of guar gum. Extrusion with citric acid influenced the physical properties and resistant starch content of the extrudate. Expansion ratios were lower for samples extruded with citric acid, and decreased as starch–gum concentration increased. The apparent viscosity of the extrudate increased with increasing guar gum concentration; however, citric acid at 2.0% concentration was found to lower the viscosity of the extrudate. Resistant starch content increased from 6.23% for extruded starch only to 14.21% for starch–gum extrudate, and further enhanced to 16.19% with the addition of 2.0% citric acid to the starch–gum extrudate. Resistant starch increased with increase of gum concentration and decreased with increase of starch–gum concentration from 7.5% to 12.5%.     

亚麻籽胶对糯米淀粉凝胶冻融稳定性影响

为了解亚麻籽胶对糯米淀粉凝胶冻融稳定性的影响,利用差示扫描量热仪、X-射线衍射、傅里叶变换红外光谱仪和扫描电镜测定添加不同比例亚麻籽胶的糯米淀粉凝胶经过7次冻融循环后的热力学特性、结晶性、分子结构和微观结构。结果显示,亚麻籽胶能显著降低糯米淀粉凝胶的析水率;淀粉凝胶熔融焓/糊化焓降低显示糯米淀粉凝胶老化受抑制;随着亚麻籽胶添加量增大糯米淀粉凝胶相对结晶度降低,显示亚麻籽胶抑制了淀粉凝胶的重结晶;亚麻籽胶使淀粉凝胶羟基伸缩振动峰发生较大的位移,增强分子间氢键作用力,而没有生成新的基团;添加亚麻籽胶的淀粉凝胶微观结构表面光滑平整,凹洞较小,基质较紧密。说明亚麻籽胶能提高糯米淀粉凝胶的冻融稳定性。     

马铃薯淀粉和豌豆淀粉复配体系的流变与凝胶特性研究

以马铃薯淀粉和豌豆淀粉按照一定的比例进行复配,采用动态流变仪和质构仪测定复配体系的糊化、流变特性及凝胶强度。结果表明:复配体系的糊化温度随着马铃薯淀粉比例的增大而有所下降,由70.1℃降低到64.6℃;在淀粉质量分数为6%的体系中,马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的弹性模量G′较大(分别为810.1 Pa和814.7 Pa),而在比例为1∶3或1∶5时复配体系的粘性模量G″较大(分别为41.0 Pa和41.6 Pa);马铃薯淀粉和豌豆淀粉的比例为1∶5和1∶11时复配体系的Tanδ较小,此配比的两个复配体系具有较好的凝胶形成能力,且凝胶强度较大(98.5~100.1 g)。      

Influence of sucrose on thermal and pasting properties of tapioca starch and xanthan gum mixtures

Sugars and hydrocolloids are used in starch-based product formulations during processing for improving the final quality of foods. Effect of sucrose (0–30%) on thermal and pasting properties of 5% w/w tapioca starch (TS) – xanthan gum (Xan) mixtures was investigated using differential scanning calorimeter (DSC), rapid visco-analyser (RVA) and rheometer. Sucrose increased gelatinization temperatures and enthalpies of TS and TS/Xan dispersions. RVA pasting temperatures, peak viscosity, final viscosity, breakdown and setback values of TS/Xan mixtures increased with increasing sucrose concentration (p < 0.05). Addition of sucrose in all TS/Xan pastes increased the rate of viscosity breakdown during RVA heating under constant shear and temperature. Setback values of TS/Xan pastes increased with sucrose addition but decreased significantly with increasing Xan content. Xan enhanced thermal stability of steady shear viscosities to TS pastes with and without sucrose. Linear regression from pasting profile revealed a good relationship for predicting final viscosity. These results could facilitate the development of TS-based products with improved thermal and pasting properties.     

黄原胶的流变特性及其在食品工业中的应用

黄原胶是一种广泛应用与食品、化工等领域的微生物多糖,本论文主要论述了黄原胶的分子结构、流变性质及其在食品工业中的应用.