不同添加物质对羟丙基木薯淀粉流变特性的影响

淀粉糊流变特性是影响淀粉类食品加工品质的主要因素。本文利用C-LTD80 RheolabQC流变仪测定了不同添加物质对羟丙基木薯淀粉流变特性的影响,结果表明：添加不同的物质均未改变羟丙基木薯淀粉糊的流体类型,各流变参数经Herschel-Bulkley模型进行拟合,拟合系数接近1。单甘酯、食盐、柠檬酸使羟丙基木薯淀粉糊的剪切应力不同程度降低,黏稠系数K减小,流变特性指数n增加;蔗糖酯、酪朊酸钠、黄原胶、CMC、瓜尔豆胶、蔗糖使羟丙基木薯淀粉糊的剪切应力明显提高,黏稠系数K增加,流变特性指数n减小。该结果对羟丙基木薯淀粉类食品深加工开发具有较大的指导意义。     

羟丙基木薯淀粉流变特性的研究

利用C-LTD80 RheolabQC流变仪,研究了不同质量浓度、温度、加热时间和pH值条件下羟丙基木薯淀粉糊的流变性。结果表明:羟丙基木薯淀粉糊是假塑性非牛顿流体,流变特性服从Herschel-Bulkley模型。随着质量浓度增大,非牛顿性增强,黏稠系数k增大;随着温度升高,非牛顿性减弱,黏稠系数k减小;随着加热时间延长,非牛顿性呈现先增强后趋于平稳的趋势,黏稠系数k先增大后减小;在pH2.5～11.5范围内,非牛顿性呈现先增强后减弱的趋势,黏稠系数k先增大后减小。     

添加剂对莲藕淀粉糊流变特性的影响

测定了不同添加物对莲藕淀粉糊剪切应力和表观黏度的影响,结果表明:添加剂不改变莲藕淀粉糊的流体类型;单甘酯、蔗糖、磷酸盐使莲藕淀粉糊的剪切应力不同程度降低,表观黏度也相应降低;CMC、食盐、黄原胶使莲藕淀粉糊的剪切应力明显提高,表观黏度稍有增大。     

羟丙基交联木薯淀粉对面团特性及挂面品质的影响

研究了羟丙基交联木薯淀粉对面团特性及挂面品质的影响,结果表明,羟丙基交联木薯淀粉可有效改善面团的面筋特性、粉质、拉伸和糊化特性,使面团的吸水率增大,提高糊化黏度和峰值时间,降低糊化温度、回生值和衰减值;添加0％～ 1.2％的羟丙基交联木薯淀粉可有效提高面团的面筋指数、稳定时间、拉伸能量、延伸度和拉伸阻力,降低弱化度;添加0％～0.8％的羟丙基交联木薯淀粉可有效延长面团的形成时间;添加羟丙基交联木薯淀粉可提高挂面的白度和亮度,增加挂面的弹性、硬度,改善挂面的烹煮品质;添加0％～1.2％的羟丙基交联木薯淀粉可有效改善生挂面的断裂强度,提高感官品质.综合分析,在本试验条件下,确定羟丙基交联木薯淀粉的最佳添加量为1.2％.     

三种羟丙基二淀粉磷酸酯对木薯淀粉特性的影响

为了研究三种羟丙基取代度相同、交联程度不同的羟丙基二淀粉磷酸酯（HDP）对木薯淀粉（TS）特性的影响，本文测定了三种羟丙基二淀粉磷酸酯的交联度，进行了淀粉糊液状态观察，在木薯淀粉中分别添加三种羟丙基二淀粉磷酸酯后，测定淀粉体系的冻融稳定性，并通过透明度测定、质构分析（TPA）和差示扫描量热法（DSC）对三种羟丙基二淀粉磷酸酯的添加对木薯淀粉老化性质的影响进行了研究。研究发现，添加三种羟丙基二淀粉磷酸酯均降低了木薯淀粉的析水率；在4℃储存过程中，添加羟丙基二淀粉磷酸酯后，木薯原淀粉的硬度有所改善，其透明度下降速率变缓，熔融焓值（ΔH）降低。三种羟丙基二淀粉磷酸酯的添加均改善了木薯淀粉的冻融稳定性，抑制了木薯淀粉的老化，而交联度较高的两种羟丙基二淀粉磷酸酯效果更佳。     

羟丙基化对木薯淀粉糊性质的影响

羟丙基化对改善木薯淀粉糊的性质具有重要作用。作者用不同醚化程度的羟丙基木薯淀粉进行试验，测定其Ｂｒａｂｅｎｄｅｒ粘度性质、冻融稳定性和糊透明度。结果表明，羟丙基化能大大提高淀粉糊的热粘、冷粘稳定性和抗剪切性能，使糊的透明度和冻融稳定性增加，当分子取代度大于０．１时，冻融稳定性高达３５次以上。作者还发现，深度羟丙基化木薯淀粉具有特殊的絮凝性质，能溶于冷水，当水溶液加热到一定温度时，溶液发生浑浊，进而絮凝成为胶状物质。胶状物质可从热水中取出，并复溶于冷水，在热水中再絮凝成胶，重复多次。     

高取代度羟丙基木薯淀粉流变特性研究(I)流变特征及羟丙基取代度的影响

研究了高取代度羟丙基木薯淀粉溶液（分子取代度ＭＳ＝１．６～４．５）的流变特性及羟丙基取代度对流变特性的影响规律。结果表明，高取代度羟丙基木薯淀粉呈现假塑性流体特征，符合幂定律τ＝Ｋγｍ。ｍ值在０．７～０．８范围，表明羟丙基化使木薯淀粉偏近牛顿流体。高取代度羟丙基木薯淀粉具有触变性和剪切稀化性质，并随溶液浓度升高而增大。羟丙基取代度对木薯淀粉流变特性有很大影响，当ＭＳ≤３．５时，溶液的表观粘度和剪切稀化现象随ＭＳ的增高而减小，当ＭＳ＞３．５时，溶液的表观粘度和剪切稀化现象随ＭＳ的增高而增大。这种变化规律符合羟丙基化反应机理。     

玉米醇溶蛋白对木薯淀粉理化性质的影响

以木薯淀粉为原料,考察不同质量分数(0%、0.5%、1.0%、5.0%)的玉米醇溶蛋白对木薯淀粉凝胶微观形貌、质构特性、流变性质和热力学性质的影响。研究结果表明,玉米醇溶蛋白使木薯淀粉凝胶颗粒表面变得粗糙,当添加量进一步增加时,其表面同时出现了凹槽和孔洞;玉米醇溶蛋白可降低木薯淀粉凝胶的硬度、黏附性,胶黏性和咀嚼性,增强木薯淀粉凝胶的内聚性和回复性;玉米醇溶蛋白会使木薯淀粉的剪切应力和表观黏度减小,浓度越小影响越大,使木薯淀粉的储能模量和损耗模量增加,1%时影响最大;玉米醇溶蛋白的加入抑制了木薯淀粉的糊化,浓度大的影响越大。     

交联程度对木薯淀粉特性的影响

为探讨交联作用对木薯淀粉凝胶的影响,利用快速黏度分析仪和动态流变仪研究不同交联度木薯淀粉的糊化特性和流变特性。黏度特性测试结果表明,随着交联度的增加,交联木薯淀粉的回生值和最终黏度先增加后减小,崩解值减小。由静态流变测试结果可知,不同交联木薯淀粉屈服应力T0大于0,流动指数n均小于1,表明该实验条件下木薯淀粉糊均为屈服-假塑性流体。淀粉糊(质量分数为6%)动态流变测试结果表明,在0.1~10.0 Hz频率范围内,交联木薯淀粉的储能模量(G’)和损耗模量(G")均高于原木薯淀粉G’和G";在4℃条件下老化2 h,适当的交联可以使木薯淀粉G’升高,损耗角正切值(tanδ=G"/G’)降低。淀粉糊(质量分数为15%)动态流变测试结果表明,在整个升温和降温过程中,交联木薯淀粉的G’和G"大于原木薯淀粉,降温过程中,淀粉凝胶的G’随交联度增加迅速增加,表现出更优越的凝胶特性。     

高取代度羟丙基木薯淀粉流变特性研究（I）：流变特征及羟丙基取代度 …

研究了高取代度羟丙基木薯淀粉溶液（分子取代度ＭＳ＝１．６￣４．５）的流变特性及羟丙基取代度对流变特性的影响规律。结果表明，高取代度羟丙基木薯淀粉呈现假塑性流体特征，符合幂定律τ＝Ｋγ＾ｍ。ｍ值在０．７￣０．８范围，表明羟丙基化使木薯淀粉偏近牛流体。高取代度羟丙基木薯淀粉具有触变性和剪切稀化性质，并随溶液浓度升高而增大。羟丙基取代度对木薯淀粉流变特性有很大影响，当ＭＳ≤３．５时，溶液的表观粘度和剪切     

Flow properties of fruit fillings

The flow properties of the fluid portion of fruit fillings were assessed to investigate the effects of gums. Results indicated that the shear rate–shear stress relations of the fluid portion of commercial fruit fillings and the model fillings made of waxy corn starch, fructose, citrate buffer, and a gum which could be guar gum, locust bean gum, CMC, xanthan gum or κ-carrageenan, fit well into the Herschel–Bulkley equation for pseudoplastic fluids. The fluid portion of the commercial fruit fillings was characterized with a yield stress between 39–51 Pa, a consistency index between 52–104 Pa·sⁿ, and a flow index (n) around 0.4. In addition, the shear rate–shear stress relations could be fitted into a modified Herschel–Bulkley equation with a flow index fixed at 0.4. Addition of guar gum, locust bean gum and CMC increased while xanthan gum and κ-carrageenan decreased the consistency and flow indices in the modified Herschel–Bulkley equation. The effect of gum addition on the apparent viscosity of model fillings varies with the type of gum, amount of addition, and shear rate.     

Influence of selected hydrocolloids on triticale starch rheological properties

The aim of the study was to define the influence of selected nonstarch polysaccharides (guar gum, xanthan gum and arabic gum) on several rheological properties of triticale starch pastes/gels, at constant polysaccharide concentration (6.5 g/100 g). These included pasting characteristics, flow curves at 50 °C and mechanical spectra at 25 °C. It was found that the presence of a gum in a system modified the rheological properties of triticale starch gels/pastes, depending on the type and concentration of the gums. In the case of guar and xanthan gums, higher pasting viscosity was observed and the shear stress was increased compared with native starch. The presence of guar gum reduced the degree of thixotropy hysteresis, negative values for this being found for systems with xanthan in spite of their shear‐thinning behaviour. Systems containing arabic gum displayed lower values of pasting and flow viscosity. The type and concentration of gums added to the polysaccharide influenced the viscoelastic properties of the gels.     

Effect of Modified Starches on Rheological Properties of Ketchup

The aim of this work was to study the effect of commercial modified starches of different origin on rheological properties of ketchup. The following starches were used to produce the ketchup samples: chemically modified potato (acetylated distarch adipate from potato starch), waxy maize (acetylated distarch adipate from waxy maize starch and hydroxypropyl distarch phosphate from waxy maize starch), and cassava (acetylated distarch adipate from cassava starch) starches and physically modified cassava and waxy maize starches (physically modified cassava starch and physically modified waxy maize starch). The SEM microphotographs revealed that swollen or disrupted starch granules were present in the ketchup samples. As was evaluated by particle size distribution analysis, two peaks characteristic for different starch granule sizes were observed, the first peak at about 100 μm for ketchup thickened with potato starch and the second one at about 50 μm for the rest of the samples. Ketchups showed non-Newtonian, shear-thinning flow with tendency to yield stress. Values of the rheological parameters describing the flow curves significantly correlated with Bostwick consistency. Ketchup samples exhibited different susceptibility for temperature changes, while values of flow activation energy were from 4.18 to 9.00 kJ/mol. On the basis of mechanical spectra, it is noted that values of G′ were higher than these of G″ showing that elastic properties dominated over the viscous ones. Ketchup samples exhibited properties of weak gels which were estimated from the values of G′ and G″ moduli and their relation and from values of tangent of phase angle (tan δ = 0.14???0.37). Principal component analysis revealed both similarities and differences in rheological behavior of the examined ketchup samples thickened with different modified starches.     

Steady and Dynamic Shear Rheology of Rice Starch‐Galactomannan Mixtures

Rheological properties of rice starch‐galactomannan mixtures (5%, w/w) at different concentrations (0, 0.2, 0.4, 0.6 and 0.8%, w/w) of guar gum and locust bean gum (LBG) were investigated in steady and dynamic shear. Rice starch‐galactomannan mixtures showed high shear‐thinning flow behaviors with high Casson yield stress. Consistency index (K), apparent viscosity (η_a,100) and yield stress (σ_oc) increased with the increase in gum concentration. Over the temperature range of 20–65°C, the effect of temperature on apparent viscosity (η_a,100) was described by the Arrhenius equation. The activation energy values (E_a = 4.82–9.48 kJ/mol) of rice starch‐galactomannan mixtures (0.2–0.8% gum concentration) were much lower than that (E_a = 12.8 kJ/mol) of rice starch dispersion with no added gum. E_a values of rice starch‐LBG mixtures were lower in comparison to rice starch‐guar gum mixtures. Storage (G′) and loss (G′′) moduli of rice starch‐galactomannan mixtures increased with the increase in frequency (ω), while complex viscosity (η*) decreased. The magnitudes of G′ and G′′ increased with the increase in gum concentration. Dynamic rheological data of ln (G′, G′′) versus ln frequency (ω) of rice starch‐galactomannan mixtures have positive slopes with G′ greater than G′′ over most of the frequency range, indicating that their dynamic rheological behavior seems to be a weak gel‐like behavior.     

沙蒿籽胶对马铃薯淀粉凝胶的热学性能、质构特性、流变特性的影响

为探究沙蒿籽胶的提取工艺,并研究沙蒿籽胶对马铃薯淀粉凝胶特性的影响,采用超声波辅助水提法提取沙蒿籽胶,利用正交试验得出其最优条件,将其得到的沙蒿籽胶添加至马铃薯淀粉凝胶中,通过差示扫描量热仪、扫描电镜等研究其对淀粉糊各项性能的影响。结果表明:料液比为1:40,温度50 ℃,时间1.5 h,沙蒿籽胶得率最高,达20.7%;添加沙蒿籽胶后马铃薯淀粉凝胶的糊化起始温度和糊化终止温度升高,焓值ΔH增大;微观结构观察表明,添加较低水平（0.1%～0.5%）沙蒿胶量的淀粉糊网络结构越来越致密,孔洞分布均一,空隙较小;同时观察淀粉糊的质构特征发现硬度、弹性等均增大;动态流变实验表明,在较低水平（0.1%～0.5%）沙蒿籽胶添加量下,G'、G'值明显升高,马铃薯淀粉糊的粘弹性提高,tanδ值明显降低,随后在较高水平（1.0%）沙蒿籽胶添加量下,G'、G'值明显下降;静态流变实验表明,添加沙蒿籽胶处理的马铃薯淀粉均为假塑性流体,并且淀粉糊稠度系数K增大,流体指数n减小,沙蒿籽胶添加量为0.3%的马铃薯淀粉糊,触变环面积减少,体系的剪切稳定性提高。因此,添加较低水平（0.1%～0.5%）沙蒿籽胶能够增强马铃薯淀粉凝胶质构性能,过高添加量（1.0%）反而对其凝胶质构性能产生不利影响。     

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。     

Rheological Characterization of Binary Combination of Gleditsia triacanthos Gum and Tapioca Starch

In the current study, Gleditsia triacanthos gum and tapioca starch were combined and rheological characterization of the binary mixture was performed. Gleditsia triacanthos gum at four different concentrations (0.1, 0.4, 0.7, and 1.0%, w/v) was mixed with tapioca starch at a constant level (2.5%, w/v). Steady shear and dynamic shear rheological properties of samples were determined using a stress/strain controlled rheometer at a constant temperature (25ºC). Oswald de Waele model was used to describe the shear rate effect on apparent viscosity values of the samples. Increase in the Gleditsia triacanthos level increased the apparent viscosity and consistency coefficient of the samples. Similarly, dynamic shear rheological parameters of the samples increased with the increase of Gleditsia triacanthos gum. The concentration of 0.7% for Gleditsia triacanthos gum was determined to be cross point for the liquid–solid phase. From this level, the elastic behavior became more dominant compared to viscous behavior because tangent delta was equal to one in this concentration. To describe the effect of Gleditsia triacanthos level on the studied rheological parameters, the Power law and exponential type models were used.     

Controlling rheology and structure of sweet potato starch noodles with high broccoli powder content by hydrocolloids

Incorporating high volume fractions of broccoli powder in starch noodle dough has a major effect on its shear modulus, as a result of significant swelling of the broccoli particles. Several hydrocolloids with distinct water binding capacity (locust bean gum (LBG), guar gum, konjac glucomannan (KG), hydroxypropyl methylcellulose (HPMC) and xanthan gum), were added to systems with 4 and 20% (v/v dry based) broccoli particles, and the effect of this addition on dough rheology, mechanical properties and structure of cooked noodles was investigated. Hydrocolloids with low (LBG and guar gum) and intermediate (KG) water binding capacity had no significant effect on shear rheology of the dough. Adding hydrocolloids with high water binding capacity (HPMC and xanthan gum) decreased the shear modulus of dough with 20% broccoli particles significantly. CLSM analysis of cooked noodles showed that in samples containing xanthan gum there was also an inhibition of swelling of starch granules. Strength and stiffness of cooked noodles with 20% broccoli particles were higher for samples containing xanthan gum, than samples without xanthan gum. The cooking loss and swelling index of samples with added hydrocolloids were slightly lower than samples without hydrocolloids. Our results showed that hydrocolloids with high water binding capacity can be used to control the degree of swelling of vegetable particles and starch granules in starch noodle products, and thereby control both dough rheology and textural properties of the cooked noodles.     

Effect of non-starch polysaccharides on the in vitro digestibility and rheological properties of rice starch gel

The starch digestibility and rheological properties of gels were evaluated in the presence of three non-starch polysaccharides (agar, xanthan gum and konjac glucomannan) with rice starch. Each polysaccharide was added to 30% (w/w) rice starch suspension at defined concentrations and starch gels were prepared. The extent of starch gel digestibility was determined by an in vitro method and rheological properties by a dynamic oscillatory test and a compression test. The added polysaccharides suppressed starch hydrolysis in the gels compared with the control, and a concentration dependency of this suppressive effect was observed. Adding agar and xanthan gum increased the storage shear modulus (G′) of starch gels, while adding konjac glucomannan decreased G′ values. The results indicate that the suppressive effect of non-starch polysaccharides on starch digestibility appears to be not only due to the rigidity of the gel, but also the interaction between starch and non-starch polysaccharides.