黄原胶流变学特性的研究

分别研究了黄原胶浓度、温度、热处理时间、pH值、抗氧化剂VC、氧化剂H2O2、金属离子以及大豆分离蛋白对黄原胶黏度的影响.实验结果表明,随着黄原胶浓度的增大,黏度增大直至基本不变;温度、热处理时间使其黏度稍微有所下降:pH值为6.0时,黏度最大;抗氧化剂VC、氧化剂H2O2使黏度降低;随着金属离子Na+、Fe2+浓度的增大,黄原胶黏度呈下降变化;大豆分离蛋白使黄原胶黏度有所增加.     

脂质体对黄原胶流变特性的影响

为研究脂质体对黄原胶流变特性的影响,采用R/S+流变仪测定了不同因素下脂质体-黄原胶复合物的流变学特性,并通过Power Law模型对流动曲线进行拟合分析。结果表明,随着脂质体添加量的增加,脂质体-黄原胶体系的表观黏度减小、触变环面积先增大后减小;随着离子强度的增强,脂质体-黄原胶体系的表观黏度减小,触变环面积增加;p H值对脂质体-黄原胶体系的表观黏度和触变环面积有显著影响;吐温80/大豆卵磷脂比例、复合时间、超声时间等因素对黄原胶流变特性影响不显著。流体指数n小于1,故脂质体-黄原胶体系为假塑性流体,具有剪切稀化特征。该研究为脂质体改善黄原胶流变特性方面提供了一定的理论支持。     

黄原胶与魔芋胶的协效凝胶性研究

黄原胶与魔芋胶均为非凝胶多糖,但二者在一定条件下共混可以得到凝胶。当黄原胶与魔芋胶以0.7/0.3的配比共混,多糖总浓度为1%时,二者的协效凝胶性最强,即凝胶强度最大,同时对制备温度和体系盐离子浓度对多糖共混凝胶性的影响作了初步研究,研究表明,当制备温度80℃,盐离子浓度为0.2mol/L,凝胶强度最大。     

酸乳流变学特性的初步研究

采用德国产HAAKEROTOVISICORV12型黏度测定仪 ,对黏性和非黏性酸乳的流变学特性进行了测定 ,分析了影响酸乳流变特性的因素 ,结果表明 :在 2～ 3 5℃的范围内 ,黏性和非黏性酸乳都是触变性流体 ;在配料和工艺相同的条件下 ,由产黏菌株形成的酸乳在大多数情况下表观黏度比非产黏菌株酸乳大 ,但有时反而小 ,初步分析这是由其微观结构的不同造成的 ;配料中无脂乳固体 (SNF)和乳脂肪的含量对酸乳的表观黏度具有强烈的影响 ,在一定条件下 ,后者影响力稍大于前者     

黄原胶的流变性及与魔芋胶等的协效性研究

研究前期筛选获得一株多糖胶质高产菌Xanthomonas axonopodis所产的黄原胶FJAT-10151-DTJZ的品质,为该黄原胶的开发应用提供基础数据及参考。通过分析浓度、剪切速率、p H、加热温度、时间、冻融处理等对FJAT-10151-DTJZ粘度的影响研究其流变性,并研究其与结冷胶、黄原胶、凝胶多糖、瓜尔豆胶、刺槐豆胶、魔芋胶、果胶和壳聚糖8种胶的协效性。实验结果表明,FJAT-10151-DTJZ溶液的粘度随浓度的升高而升高,且为非牛顿流体;当FJAT-10151-DTJZ的浓度为1%时,其粘度为343 m Pa·s;p H、冻融对FJAT-10151-DTJZ的粘度影响不大;FJAT-10151-DTJZ的最佳加热温度为75℃;粘度随加热时间先增大后减小,当加热温度为75℃,加热时间为150 min,1%浓度的FJAT-10151-DTJZ溶液的粘度为808 m Pa·s。FJAT-10151-DTJZ只与魔芋胶有强烈的协同增效作用,与壳聚糖、结冷胶、黄原胶、凝胶多糖、瓜尔豆胶、刺槐豆胶、果胶无协效性。      

黄原胶的流变学及加工特性的研究

系统研究了黄原胶的流变学特性、持水性和冻融稳定性。结果表明:黄原胶为剪切变稀的假塑性流体,属于热可逆凝胶;黄原胶的冻融稳定性良好但其持水力较差。     

黄原胶表面施胶工艺

通过对黄原胶性能的分析、试验,摸索出黄原胶的表面施胶工艺。     

黄原胶对酸乳凝胶特性的影响及其作用机理探讨

为探索增稠剂对酸乳体系的影响作用机理,以在原料鲜牛乳中分别加入0·0%、0·1%、0·2%、0·3%的黄原胶制作的酸乳为材料,对其流变特性和微观结构进行了观测。结果表明:4种样品都是正触变性流体,其触变环面积之比为1∶1·08∶0·64∶0·77。在加入量为0·1%、0·2%和0·3%的三个样品中,随着黄原胶加入量的增加,酸乳样品的表观黏度和剪切应力逐渐降低。电镜观察显示,不加入黄原胶时酪蛋白相互凝集成立体网状结构,加入黄原胶后酪蛋白凝集胶束变成了散乱的片状结构。初步分析认为,黄原胶对酸乳发生作用的机理是通过其大分子的空间位垒效应干扰酪蛋白发生凝集的方式,导致酪蛋白胶束结构散乱,从而降低酸乳凝胶的表观黏度和剪切应力。      

黄原胶对酸乳凝胶特性的影响及其作用机理探讨

为探索增稠剂对酸乳体系的影响作用机理,以在原料鲜牛乳中分别加入0.0%、0.1%、0.2%、0.3%的黄原胶制作的酸乳为材料,对其流变特性和微观结构进行了观测.结果表明:4种样品都是正触变性流体,其触变环面积之比为1:1.08:0.64:0.77.在加入量为0.1%、0.2%和0.3%的三个样品中,随着黄原胶加入量的增加,酸乳样品的表观黏度和剪切应力逐渐降低.电镜观察显示,不加入黄原胶时酪蛋白相互凝集成立体网状结构,加入黄原胶后酪蛋白凝集胶束变成了散乱的片状结构.初步分析认为,黄原胶对酸乳发生作用的机理是通过其大分子的空间位垒效应干扰酪蛋白发生凝集的方式,导致酪蛋白胶束结构散乱,从而降低酸乳凝胶的表现黏度和剪切应力.     

糙米酵素流变学特性研究

研究糙米粉在不同温度和浓度条件下剪切速率和表观黏度的变化关系,并确定在各温度和浓度条件下其稠度系数和流变指数,建立流变学方程.试验结果表明,糙米粉的黏度随温度的升高而增大,且发酵后的糙米酵素粉黏度随温度的变化范围大于未发酵;糙米粉的黏度随浓度的增大而增大,且发酵后的糙米粉黏度随浓度的变化范围小于未发酵的.     

黄原胶的流变性及在织物印花中的应用

通过测定黄原胶各项流变指数，研究其独特的流变性能，探讨其应用于分散染料印花中作为增稠剂的可能性；比较了黄原胶与海藻酸钠和丙烯酸类合成增稠剂的各项流变指数和印花性能。研究结果表明，黄原胶色浆在印花中可提供良好的轮廓清晰度和抱水性，但得色量不高，可通过添加适量的表面活性剂以改善其得色量。     

Rheological study of xanthan and locust bean gum interaction in dilute solution

An oscillatory capillary rheometer was used to investigate visco-elastic properties of xanthan and locust bean gum (LBG) blends in dilute solution. Gums were evaluated for intrinsic viscosity and the elastic component. Molecular conformation of the complex of xanthan–LBG was assessed by the power law and the Huggins equations. A 60% xanthan–40% LBG blend exhibited the strongest attraction between xanthan and LBG molecules as evidenced by a greater intrinsic viscosity, the polymer miscibility coefficient α, the elastic component, and a positive Huggins coefficient K_m. The power-law model was successfully applied to predict the molecular conformation of xanthan and LBG alone in dilute solution and was exhibited as rod-like and random coil conformation. The power-law coefficient b increased as the LBG fraction increased in the blends, suggesting a more flexible xanthan–LBG complex dependent on LBG.     

Rheological properties of emulsions containing milk proteins mixed with xanthan gum

Oil in water emulsions (30% w/w) containing mixtures of milk proteins with xanthan gum were rheologically characterized at ambient temperature and the evolution of their properties was measured during a month under cold storage. The milk proteins used were sodium caseinate and whey concentrate at 2% mixed with xanthan gum at 0.3% or 0.5%. Emulsions properties were compared to those of respective aqueous systems and in general showed same rheological behaviour as their respective aqueous system, however, emulsions presented higher consistency index, due to oil droplets concentration. The flow behaviour index showed a small variation, increasing its value slightly. The consistency of emulsions with xanthan was similar, independently of the milk protein used, confirming that xanthan rheology predominates on emulsion rheology.     

四种变性淀粉与黄原胶和魔芋胶复配体系粘度特性研究

目前对变性淀粉与黄原胶和魔芋胶复配体系粘度特性以及其抗酸和抗剪切方面的研究尚鲜见报道。本研究以变性淀粉:木薯羟丙基二淀粉磷酸酯（HDP-CS）、木薯乙酰化二淀粉磷酸酯（ADP-CS）、马铃薯乙酰化二淀粉磷酸酯（ADP-PS）、马铃薯乙酰化双淀粉己二酸酯（ADA-PS）分别与黄原胶（XG）、魔芋胶（KG）进行复配,以粘度为考察指标,测定复配体系的抗剪切性和抗酸性,筛选最佳组合。在各配比浓度的基础上,分析两者复配体系的特性,通过对其协效性、回归方程和显著性进行分析确定最佳配比浓度。结果表明:通过对抗剪切性和抗酸性的测定结果分析,最佳复配体系为:马铃薯乙酰化二淀粉磷酸酯—黄原胶和木薯羟丙基二淀粉磷酸酯—魔芋胶复配体系;前者复配体系随变性淀粉浓度的变化而呈线性变化,后者呈指数变化。两复配体系的最佳配比浓度为:ADP-CS:XG=2%:0.4%（g/g）;HDP-CS:KG=2.5%:0.4%（g/g）,此研究结果比前人研究有所改善。      

Rheological and structural characteristics of peach tree gum exudate

The peach tree (Prunus persica), after mechanical injury or infection by microorganisms, produces a copious gum exudate on its trunk and branches. After aqueous extraction, peach gum (cv. ‘chimarrita’) yielded a soluble aqueous extract (AE) and a particle-rich hydrogel fraction (RG). After freeze-drying, AE was solubilized in water and added to excess ethanol to give a polysaccharide (POLY) precipitate. RG, AE, and POLY were composed of Ara, Xyl, Man, Gal, and uronic acids in 46:14:2:32:6, 54:12:1:27:6, and 47:13:1:33:6 molar ratios respectively, with traces of Rha. The ¹³C NMR spectra of all fractions were similar, with C-1 signals of α-l-Araf (δ 109.6–107.4) and main ones from β-d-Galp units (δ 103.7, 103.2), suggesting the presence of arabinogalactan-type polysaccharides. Rheological analyses were carried out with AE and POLY. Solutions of both fractions at 4% (w/v) had a non-Newtonian shear-thinning behavior, however that of AE showed higher apparent viscosity than that of POLY. The presence of salts decreased the apparent viscosity of AE dispersion. Dynamic oscillatory analyses showed that 4% (w/v) AE and POLY had a gel-like structure, being AE hydrogel a stronger gel when compared with POLY. This suggests that other compounds, in addition to polysaccharide, are involved in the gel network in aqueous dispersions of AE. Weaker gels were formed with 2% (w/v) AE in water and 4% (w/v) AE in various salt solutions. These results showed that the peach gum had an interesting rheological behavior and that it could have a future application.     

Rheological study of xanthan and locust bean gum interaction in dilute solution: Effect of salt

An oscillatory capillary rheometer was used to investigate the effects of NaCl, KCl, and CaCl₂ on visco-elastic properties of xanthan and locust bean gum (LBG) blends in dilute solution. Gums were evaluated for intrinsic viscosity and elastic component. Molecular conformation of the xanthan–LBG complex was assessed by the power-law and Huggins equations. Addition of any of the three salts reduced significantly the intrinsic viscosity and elastic component of the gum blends, with a pronounced effect from divalent ions, compared with monovalent ions. The 60% xanthan–40% LBG blend exhibited the strongest attraction between xanthan and LBG. For the three salts, the attraction weakened when 5-mM salt was added and vanished with the addition of 50-mM salt. The strongest attraction between xanthan and LBG molecules was also evidenced by a positive Huggins miscibility coefficient K_m, and a positive attraction–repulsion coefficient α. With addition of 50 mM of any of the three salts, the coefficient α became negative, suggesting a strong repulsion between the two gums. The power-law coefficient b increased as salt concentration and LBG fraction increased in the blends for the three salts, suggesting a more flexible xanthan–LBG complex dependent on salt concentrations and LBG.     

黄原胶特性及其在食品和复配胶中的应用

黄原胶具有剪切稀释、悬浮乳化、增稠、耐盐、耐酸碱、耐高温等独特性能,被广泛应用于石油开采、化工、医药、食品等多种行业.简要介绍了黄原胶的基本结构、生产工艺流程、性质和在食品及复配胶中的应用,重点论述了黄原胶在肉制品、面制品、饮料中的应用及与卡拉胶、刺槐豆胶和魔芋胶的配伍性.     

Rheological and structural properties of oleogel base on soluble complex of egg white protein and xanthan gum

Oleogels can be used to provide solid-like properties without using high levels of saturated fatty acids. In this study, the edible oleogels structure developed based on egg white protein (EWP) (5%) and xanthan gum (XG) (0%, 1%, 0.5%, and 0.75% wt/wt) complex by using aerogels system as a template for oleogel preparation. The effect of pH on the EWP-XG mixture indicated the creation of a soluble complex of EWP-XG in pH 5.5. The Fourier-transform infrared spectroscopy confirmed the interaction between EWP and XG. The amount of absorbed oil was considerably higher in EWP-XG aerogels. SEM showed a soft surface in EWP 5% aerogel, which can be the reason for its less oil absorption. The aerogel and oleogel including more XG concentration had a stronger network structure and created more elastic oleogels. The light microscopy images revealed by increasing of XG concentration, the structure of protein gel mesh became more compact and regular. The XRD patterns of the aerogels did not show any clear differences between crystallinity of the samples. Therefore, it can be concluded that the aerogels based on the structuring of EWP-XG complexes have a high potential as a three-dimensional network for the oil absorption and creating oleogel.