不同大米类型淀粉凝胶的质构特征

从籼型、粳型、香型三种类型的大米中提取淀粉,采用低温法制备大米淀粉凝胶,用质构仪二次压缩模式测定淀粉凝胶的质构特性,研究碘兰值和酶解力对淀粉凝胶质构特性的影响。结果表明,不同类型的大米低温凝胶特性有显著差异。碘兰值与淀粉凝胶特性有显著相关性,黏附性用碘兰值指数模型表示,弹性用碘兰值线性表示都具有很高的拟合精度。     

Mechanical behavior of starch films

Zener's model, which considers viscoelastic components of sizing film behavior, is developed using data from axial tension tests. The stress–strain results at different size formulations are used to determine model parameters. The ability of the model to predict the response to different loading conditions is examined by comparing the model simulation with the available experimental data. Tensile strength and extension of films were affected by hydrophilicity of the plasticizer and its concentration. Lower mechanical resistance when using lipid additives was also reported. The performance of a warp-sizing formulation is determined in part by the properties of lubricant type applied with it.     

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)。      

Temperature dependence of starch gel rheological properties

In an attempt to learn more about molecular mechanisms and thermodynamic preconditions of development of spatial structures of starch systems, the authors analyzed the kinetics of structuralization processes in the temperature function of the course of these processes. The method of dynamic-mechanical analysis (DMA) was employed in the performed investigations. On the basis of empirical values of G₁ and G₂, the energetic status of the gel network as well as changes in this status during the structuralization process was determined. In the state of complete hydration, the retrogradation mechanism of the examined starch systems consisted in the bundle–coil transition. This transition required a decline in the temperature of the system below temperature θ determined by the ratio of the enthalpy to entropy transition: ΔH/ΔS ≈ 322 K ≈ 49 °C. This transition is a cooperative transformation of two fragments of neighboring chains in a condition of chaotic confrontation to a state of bihelical associated molecules. The bihelical association of starch chains is the main source of stabilization of the spatial structure of starch hydrogels below the θ transition temperature.     

马铃薯淀粉糊化及凝胶特性研究

采用快速黏度分析仪(rapid viscosity analyzier,RVA)测定淀粉浓度、pH、蔗糖、柠檬酸、卡拉胶等对马铃薯淀粉糊化特性和凝胶特性的影响.结果表明:随着淀粉浓度的增加,马铃薯淀粉糊的热稳定性和凝沉性变差,凝胶性增强,容易回生;在pH 7时马铃薯淀粉的热稳定性、凝沉性和凝胶性较差,马铃薯淀粉不易回生;添加蔗糖、卡拉胶、明矾、食盐或苯甲酸钠,马铃薯淀粉的热稳定性、凝沉性、凝胶性增强;添加柠檬酸后马铃薯淀粉的热稳定性和凝沉性增强,凝胶性减弱.     

Citric acid cross-linking of starch films

This paper shows that citric acid can cross-link starch and improve the tensile strength, thermal stability and decrease the dissolution of starch films in water and formic acid. The poor mechanical properties and water stability of starch have restricted its industrial applications. Although cross-linking is a common approach to improve the properties of starch products, current starch cross-linking methods are either expensive, toxic or do not impart the desired properties to the cross-linked materials. In this research, the possibility of cross-linking starch films using citric acid to improve their strength and stability was examined. Citric acid cross-linked starch films show about 150% higher strength than non-cross-linked films and have strength better than most cross-linked starch and synthetic polymer blended films previously developed. Films cross-linked with 5% citric acid had only 35% loss in weight after being in formic acid for 5 h at 50 °C whereas the non-cross-linked films dissolved immediately.     

青稞淀粉的糊化特性及凝胶性能

以青稞淀粉(hulless barley starch,HBS)为研究对象,以市售荞麦淀粉(buckwheat starch,BS)、小麦淀粉(wheat starch,WS)为对照,比较3种淀粉糊化特性,并考察蔗糖、NaCl、酸碱介质对糊化性能的影响;对3种淀粉凝胶的质构和冻融稳定性、组成、颗粒结构、结晶度、透明度进行研究。结果表明:青稞淀粉颗粒大,呈扁平椭圆形,系A型晶体结构,结晶度为26.7%;NaCl能大幅提高青稞淀粉糊化冷稳定性,降低老化作用;3种淀粉在pH 3~11及不同糖度条件下都保持相近的糊化特性。青稞淀粉凝胶黏着性较强,硬度适中,表现出较好的冷藏稳定性和较差的冻融稳定性。     

变性淀粉复配及凝胶性能研究

明胶是一种在布丁类点心中应用广泛的食品辅料,但存在特殊人群忌食等问题,为了解决这些问题,使布丁类点心进一步推广,本文研究了以变性淀粉为主,卡拉胶、结冷胶、琼脂为辅的混合物,具体方法是将变性淀粉分别与卡拉胶、结冷胶、琼脂以不同的比率进行混合,并制成溶液,待其凝固后测定凝胶强度、弹性、析水率几方面的特性,通过各项性能的筛选,0.2%结冷胶与8%淀粉混合物的各项性能优,将此混合物与明胶分别制成溶液凝固,比较两者的弹性、析水率、凝胶强度。结果表明,当变性淀粉与结冷胶为14∶1时各项性能较为接近明胶,其中凝胶强度接近明胶,析水率优于明胶,凝胶弹性略低于明胶,从这些性能参数来看,该变性淀粉与结冷胶的混合物如果用来制作布丁类的甜点在成型和存放时的效果应比明胶的效果要好,但在耐咀嚼性方面应该略差,可以作为布丁点心类备选原料进行进一步的研究。     

用变性淀粉等添加剂改进淀粉膜强度的研究

以马铃薯淀粉为主要原料,通过制膜机制成了具有一定机械强度的可食性淀粉膜。为增加淀粉膜的机械性能,考察了变性淀粉等添加剂对淀粉膜性能的影响,试验发现添加马铃薯淀粉醋酸酯、海藻酸钠和卡拉胶等食品添加剂可以改进淀粉膜的强度。     

Improving gel formation of rice starch added with cross‐linked resistant starch prepared from rice starch

The gel formation properties of non‐waxy rice starch with cross‐linked resistant starch with phosphate (RS4, 10, 20, and 30% based on rice starch) prepared from three rice varieties with different amylose (AM) content were investigated to increase dietary fiber content, improve gel structure, and reduce the glycemic index of rice products. The AM contents of rice starches were 1.71% in Hanganchal1, 22.47% in Nampyeong, and 33.39% in Goamy. All RS4 showed A‐type crystallinity and their RS levels were 46.91, 54.54, and 66.01%, respectively. The initial pasting temperatures of RS4 added rice starches increased as RS4 contents increased, but peak and breakdown viscosities and enthalpy change (△H) reduced. The RS4 addition improved gel shape and texture properties including hardness, cohesiveness, and gumminess, except the 30% Goamy RS4 added gel. The 20% RS4 addition was appropriate to form rice starch gels. The network structure of RS4 added gel formed more regular and firmer than that of control, because RS4 granules were entrapped within the gel matrix like observed by light microscope and scanning electron microscopy. It is suggested that RS4 not only assist in forming a rigid network structure but also increasing a dietary fiber content.

     

5种豆类淀粉凝胶特性的比较研究

选取绿豆、豌豆、白芸豆、白豇豆、鹰嘴豆为原料,提取其淀粉,并制备及测定几种豆类淀粉凝胶的特性(凝胶强度及硬度、弹性、黏性等),比较分析各种豆类淀粉特性的差异。结果表明,不同淀粉浓度下,均以豌豆淀粉的凝胶强度最大,白豇豆淀粉的最小;5种淀粉的TPA质构结果显示,白芸豆淀粉凝胶在高浓度下(8%和10%)具有较大的硬度、弹性、咀嚼性和回复性;豌豆淀粉在中等浓度下具有较高的硬度、弹性、咀嚼性,但其回复性在3个浓度下均是最小的;白豇豆淀粉凝胶的硬度和咀嚼性小于其他4种豆类淀粉,但其弹性和回复性却较大;5种豆类淀粉中,豌豆淀粉的凝胶强度和TPA质构特性受浓度的影响最大,且适合在中等浓度(8%)下制作凝胶制品。相关性分析发现,豆类淀粉的凝胶强度与直链淀粉含量呈极显著正相关,而黏聚性呈极显著负相关,而其他质构参数与直链淀粉含量的关系因浓度不同而呈现差异。     

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。     

玉米淀粉与小麦淀粉复合可食用膜封合特性研究

采用单因素试验,研究封合温度、封合时间和封合压力对玉米淀粉与小麦淀粉复合可食用膜封合强度的影响,进一步采用正交试验的分析方法对封合工艺参数进行优化。结果表明,玉米淀粉与小麦淀粉可食用膜封合最佳工艺条件为封合温度140℃、封合时间1.5 s、封合压力0.4 MPa,其封合强度可以达到3.13 N/15 mm。     

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。     

细菌纤维素对大米淀粉凝胶老化的影响

为了解细菌纤维素对淀粉凝胶老化的影响,利用快速黏度分析仪、差示扫描量热仪、X-射线衍射和扫描电镜测定添加不同量细菌纤维素的大米淀粉凝胶糊化特性、热力学特性、结晶性和微观结构。结果表明,随细菌纤维素添加量的增加,大米淀粉糊化时崩解值、回生值、糊化焓值显著降低,显示细菌纤维素抑制了大米淀粉凝胶的短期老化;随细菌纤维素添加量的增加,大米淀粉凝胶老化焓值显著降低,而重结晶从13.26%降至7.93%,说明细菌纤维素抑制了大米淀粉中支链淀粉的重结晶;大米淀粉凝胶微观结构显示细菌纤维素的添加使大米淀粉凝胶的表面更加完整、结构更加致密。由此表明细菌纤维素对大米淀粉凝胶老化具有显著的抑制作用。     

Analysis of water binding in starch plasticized films

The water-binding properties of wheat starch films were studied through the determination of water vapour adsorption isotherms at 20 °C. Starch films were obtained by casting after mixing native starch at 95 °C for 15 min with different ratios of plasticizer (glycerol).     

Distribution of aroma in a starch–polysaccharide composite gel

The location of different aroma compounds in a gel containing sucrose, cross-linked waxy corn starch and carrageenan was investigated. Different systems were designed by varying the carrageenan and the sucrose contents and were flavoured with a mixture of aroma compounds. These systems are described as composite gels formed by a dispersed phase composed of swollen starch granules and a continuous phase containing the other polysaccharide. The separation of the two phases was done by centrifugation. The concentration in aroma compounds was measured in both phases and a partition coefficient was calculated for every compound in the different formulations. When the gel contained only starch, the distribution between the two phases for all aroma compounds was uniform. When carrageenan was present, the aroma compounds were found to be more concentrated in the continuous phase than in the dispersed phase. The addition of sucrose induced the opposite effect with a greater concentration of aroma compounds in the dispersed phase. The combination of these results with those of the gas/matrix partition is finally discussed to understand how the distribution of aroma compounds in a biphasic system influences aroma release in the headspace under equilibrium.     

淀粉类凝胶三维打印研究进展

食品三维打印技术是食品加工业革命性的创新发展, 能够在未来解决我国食品加工业和食品产业面临的营养个人订制性以及生产适合老人和婴幼儿的易咀嚼食品诸多问题。淀粉是食品中最常见的组分, 其在高温发生糊化并且与其他组分交联形成的凝胶体系是很好的食品三维打印材料。本文先是阐释了挤压式食品三维打印技术的工作原理, 以及淀粉的结构及物理化学性质, 揭示了淀粉的物理化学性质与淀粉类材料三维打印形状稳定性之间的联系, 从而进一步介绍了材料特性、三维打印挤出行为及后处理方法对淀粉三维打印产品形状稳定性的影响以及兼具易咀嚼特性和个性化营养特性的三维打印产品的相关研究。     

羧甲基淀粉钠与凝胶性多糖的应用及发展

分别介绍了羧甲基淀粉钠和魔芋胶、海藻酸钠与卡拉胶等三种凝胶性多糖的结构性质及其在食品等工业中的应用.羧甲基淀粉具有好的分散力和结合力、吸湿性、乳化性,稳定性好,透明度好等特点.作为食品的乳化剂、稳定剂及增稠剂,使组织细腻且可口性好,可显著提高食品品质及风味.海藻酸钠在水中具有良好的溶解特性、凝胶特性、生物相容性、成膜性、稳定性和螯合性,用作食品添加剂、澄清剂和增稠剂.魔芋胶具有良好的成膜性和凝胶性,具有流变性、增稠性、增效性、黏结性、吸水性、成膜性、衍生性等性质.卡拉胶具有形成亲水胶体、凝胶、增稠、乳化、成膜、稳定分散等特性,在食品工业中的作用主要表现在具有凝胶、增稠和蛋白反应性三个方面.同时对羧甲基淀粉钠和一种凝胶性多糖共混的一些研究作了简要阐述,并根据各自的特性展望了它们的发展方向.     

玉米淀粉和红薯淀粉对草鱼鱼糜凝胶性质的影响

以草鱼鱼糜凝胶为研究对象,从凝胶质地特性(破断强度、凹陷度、压缩功、凝胶强度)和凝胶析水率2方面研究了添加玉米淀粉和红薯淀粉对草鱼鱼糜凝胶品质的影响,结果表明:添加玉米淀粉和红薯淀粉均可改善草鱼鱼糜凝胶的质构性质,2种淀粉的适宜添加量分别为10.8%和7.2%;2种淀粉对草鱼鱼糜凝胶性质的改善作用大小不同,在各自的适宜添加量条件下,红薯淀粉对草鱼鱼糜凝胶性质的改善效果比玉米淀粉更明显。