黄原胶对酪蛋白酸钠乳状液稳定性的影响

研究了一定pH条件下,黄原胶浓度及剪切稀化效应对酪蛋白酸钠乳状液稳定性的影响。结果表明,在酸性条件下,黄原胶无法抑制酪蛋白的变性沉淀,乳液在制备之初,即产生严重絮凝。在中性和弱碱性条件下,黄原胶在一定浓度范围内,诱发了乳状液的排斥絮凝;体系的pH显著影响了乳状液的稳定性,pH6条件下,较低的黄原胶浓度(0.2wt%)便可赋予乳状液良好的稳定性。均质过程大大降低了黄原胶的粘度,导致乳状液的稳定性下降,与添加未经均质处理的黄原胶相比,添加量增大近一倍,才能获得稳定的乳状液。     

黄原胶体系的流变性及糖和盐对体系的影响

报道了对黄原胶水溶液以及以黄原胶水溶液为水相的２０％（Ｏ／Ｗ体积分数）乳状液在３０℃的流变学性质的研究。实验中通过振荡和蠕变测试考察了从０．０５％～０．５％系列质量分数的黄原胶溶液和乳状液的流变学性质以及０．５ｍｏｌ／ＬＮａＣｌ和质量分数１０％的蔗糖对这些体系的影响。发现，随着黄原胶质量分数的增加，体系逐渐表现固态的反应，这表明大分子交联或其它方式的缔合逐渐提高了体系结构化的程度。蔗糖的存在在一定程度上增强了大分子的这种功能作用，而ＮａＣｌ的引入则明显降低了大分子的这种影响，并且ＮａＣｌ的这种影响对黄原胶质量分数较高的体系更加明显。乳状液体系的测定结果与水相的情况一致。     

含酒精乳状液的稳定性

介绍了体系的 pH值 ,盐 ,小分子表面活性剂 ,黄原胶 ,蔗糖以及均质压力对含酒精的脂肪乳状液体系稳定性的影响 .通过对各种体系的粘度和分层状态的测定 ,比较了不同酒精浓度下乳浊液对各种因素的稳定性能的变化 .实验结果表明酒精的存在使 pH值、Ca2 、KCl等对酪蛋白稳定的乳状液的破坏作用更明显 ;小分子表面活性剂和较高的均质压力对提高体系的抗分层稳定性均有促进作用 ;在所添加的浓度范围内 ,黄原胶显示了与乳状液体系明显不相容性 ,体系的稳定性明显降低 ;蔗糖对体系的稳定性有一定程度的提高 .     

阴离子多糖对大豆蛋白乳状液乳析稳定性的影响

研究了卡拉胶、黄原胶和羧甲基纤维素钠(CMC)3种阴离子多糖对大豆蛋白乳状液乳析稳定性的影响。结果表明:添加0.03%卡拉胶的乳状液乳析稳定性较好,而添加CMC或0.06%以上黄原胶的乳状液乳析稳定性则较差;随着阴离子多糖浓度的增加,添加CMC的乳状液顶部粒径d3,2增大,添加卡拉胶或黄原胶的大豆蛋白乳状液顶部粒径d3,2先减小后增大;添加阴离子多糖的乳状液的顶部粒径d3,2与乳析率呈较好的正相关性。     

复配胶体对彩虹芭乐果汁饮料稳定性的影响

以彩虹芭乐果汁饮料为研究对象,采用分层程度和感官评价为考察指标,探讨了添加CMC-Na、黄原胶、果胶、结冷胶4种复配胶体对彩虹芭乐果汁饮料稳定性的影响,结果表明:随着复配胶体添加量的增加,芭乐果汁饮料的稳定性呈上升趋势,由分层程度实验结果可知,影响彩虹芭乐果汁稳定性的因素大小为结冷胶黄原胶CMC-Na果胶;由产品感官评分实验结果可知,影响彩虹芭乐果汁稳定性的因素大小为CMC-Na结冷胶黄原胶果胶,当黄原胶∶CMC-Na∶结冷胶∶果胶复配比为2∶3∶1∶1.5时,芭乐果汁饮料稳定性最好,口感最佳。     

几种稳定剂对花生乳稳定性的影响

通过Ｌ９（３＾４）正交试验设计测定了几种稳定剂及其用量对花生乳稳定性的影响，以强化分层率为指标分析了复合乳化剂ＨＬＢ值与乳化效率间的关系，结果表明：当复合乳化剂的ＨＬＢ＝１２．５￣１３．５时乳化效率最高，在花生乳中添加１％大豆分离蛋白、０．２％蔗糖脂肪酸酯、０．１％单硬脂酸甘油酯、０．２％羧甲基纤维素钠、０．０５％黄原胶后，能够得到稳定性良好的花生乳产品。     

亲水胶体对含酒精O/W(水包油)乳状液稳定性的影响

研究了卡拉胶、刺槐豆胶,及其混和胶作为稳定剂,对以酪蛋白酸钠稳定的含酒精O/W乳状液体系稳定性的影响.结果表明,单独添加一定浓度的卡拉胶可改善体系的分层稳定性,而单独加入刺槐豆胶会加速体系失稳,当m(卡拉胶)∶m(刺槐豆胶)=4∶1加入到体积分数为15%的酒精乳状液中,加入量为0.02%时体系稳定性最好.同时研究了两多糖的加入方式、热处理时间,以及蔗糖存在下对乳状液稳定性及黏度的影响.结果表明,卡拉胶与刺槐豆胶分别加入到乳状液中稳定效果较好,并且卡拉胶和刺槐豆胶分别在90℃保温6min后加入有利于体系的稳定;质量分数为10%的蔗糖存在增强了复合胶存在下体系的稳定性.     

香蕉果肉饮料的研究

研究了香蕉带果肉饮料加工工艺。为保持香蕉的天然色、香、味，探讨了香蕉果肉褐变的控制和果肉在汁中的稳定性，得出的最佳加工工艺条件为：热烫温度１００℃，热烫时间４ｍｉｎ，果泥含量２０％，糖度１３．５°ＢＸ，酸含量为０．１５％，ｐＨ４．０±０．１，添加０．０５％黄原胶和０．０２％魔芋精粉，经过２次磨胶，排气，１００℃杀菌１５ｍｉｎ。     

黄原胶在低浓度时的流变特性及影响因素研究

以低浓度黄原胶溶液为研究对象,考察了其流变特性及浓度、温度、ｐＨ值和搅拌作用对溶液粘度的影响。结果表明当浓度≤１．１０８时,黄原胶溶液呈牛顿流体,浓度〉０．１０％时为假塑性流体;不同温度和浓度的黄原胶溶液粘度符合指数律流变方程ｒ＝ＫＤ＾ｎ;低浓度的黄原胶溶液在ｐＨ５．０～９．５范围,粘度不受ｐＨ值变化的影响,搅拌作用使黄原胶溶液的粘度提高。     

多糖对灵芝孢子油乳状液稳定性的影响

该文将大豆分离蛋白与多糖混合制备蛋白-多糖复合物,并以此为乳化剂,将灵芝孢子油包埋,构建蛋白-多糖-灵芝孢子油乳状液体系。研究阿拉伯胶和黄原胶的浓度对乳状液稳定性的影响。结果表明加入一定量的多糖能明显改善乳状液的粒径分布、增大乳状液电位绝对值和增强离心稳定性。加入阿拉伯胶的乳状液抗氧化性优于黄原胶。当阿拉伯胶浓度为0.20%时,经过10 d储藏后,过氧化值（peroxide value,POV）最低,为2.35 meq/kg;0.10%黄原胶的保护效果最好,POV最小,为5.22 meq/kg。表明大豆分离蛋白-阿拉伯胶和大豆分离蛋白-黄原胶复合体制备的乳状液体系优于单纯的蛋白制备的乳状液。     

The interplay between diverse oil body extracts and exogenous biopolymers or surfactants

Hazelnuts, sesame seeds and soybeans were selected as three diverse sources of oil bodies. Application of aqueous extraction and centrifugation steps resulted in concentrated oil body creams that were studied for their physical stability after dilution to a series of 5.0 wt.% oil-in-water emulsions incorporating sodium caseinate (1.0 wt.%), Tween 80 (1.0 wt.%) or xanthan gum (0.1 wt.%). In terms of aggregation/coalescence and creaming, the stability of the oil body based emulsions was ruled to a large extent by the initial natural oil droplet size and the presence of co-extracted exogenous proteins and secondarily by the added biopolymers and the surfactant. More specifically, soybean oil bodies exhibited the highest physical stability, even though incorporation of Tween 80 into all three oil body emulsions improved the stability against aggregation/coalescence, while xanthan gum was an effective stabilizer against creaming.     

Influence of xanthan gum on the formation and stability of sodium caseinate oil-in-water emulsions

Studies have been made of the changes in droplet sizes, surface coverage and creaming stability of emulsions formed with 30% (w/w) soya oil, and aqueous solution containing 1 or 3% (w/w) sodium caseinate and varying concentrations of xanthan gum. Addition of xanthan prior to homogenization had no significant effect on average emulsion droplet size and surface protein concentration in all emulsions studied. However, addition of low levels of xanthan (≤0.2 wt%) caused flocculation of droplets that resulted in a large decrease in creaming stability and visual phase separation. At higher xanthan concentrations, the creaming stability improved, apparently due to the formation of network of flocculated droplets. It was found that emulsions formed with 3% sodium caseinate in the absence of xanthan showed extensive flocculation that resulted in very low creaming stability. The presence of xanthan in these emulsions increased the creaming stability, although the emulsion droplets were still flocculated. It appears that creaming stability of emulsions made with mixtures of sodium caseinate and xanthan was more closely related to the structure and rheology of the emulsion itself rather than to the rheology of the aqueous phase.     

Physical and Oxidative Stabilities of O/W Emulsions Formed with Rice Dreg Protein Hydrolysate: Effect of Xanthan Gum Rheology

The shortening of shelf-life of food emulsions is frequently due to poor creaming and lipid oxidation stability. The lipid oxidation of O/W emulsions can be inhibited by rice dreg protein hydrolysate (RDPH); however, emulsions were stabilized by Tween-20. Polysaccharides can control the rheology and network structure of the aqueous continuous phase by increasing viscosity and yield stress, hence retarding phase separation and gravity-induced creaming, especially for xanthan gum. The objective of this research was to evaluate whether emulsions formed with 2 wt% RDPH and stabilized by xanthan gum (0–0.5 wt%) could produce 20 % (v/v) soybean oil-in-water emulsions that had good physical and oxidative stability. The degree of flocculation of droplets as a function of xanthan gum concentration was assessed by the microstructure, rheology, and the creaming index of emulsions. Addition of xanthan gum prior to homogenization had no significant effect on the mean droplet diameter in all emulsions studied. Increase in xanthan gum concentration led to the increase in creaming stability of emulsions, due to an increase in viscosity of the continuous phase and/or the formation of a droplet network with a yield stress, as well as the enhanced steric and electrostatic repulsion between the droplets. Lipid oxidation of the emulsions was significantly inhibited at xanthan gum concentrations of 0.12 wt% or above with RDPH, which could due to the fact that xanthan gum increases the viscosity of the aqueous phase and hindered the diffusion of oxidants to the oil droplet surface area, synergistic effect between RDPH and xanthan gum to suppress oil peroxidation, and metal ion chelation capability of xanthan gum. Thus, stable protein hydrolyzates-type emulsions could be obtained with increasing concentration of xanthan gum.     

面筋蛋白粒子-黄原胶Pickering乳液的制备及其表征

制备黄原胶与面筋蛋白纳米粒协同稳的Pickering乳液,表征Pickering乳液的物理化学性能和微观结构。结果显示：通过黄原胶与面筋蛋白纳米粒协同作用,可制备出稳定性较好的Pickering乳液。低质量分数的黄原胶（0.2%）会促进乳析;当黄原胶质量分数不小于0.3%时,乳液于4 ℃贮存30 d仍无乳析现象;当黄原胶质量分数为1%时,贮存30 d乳液出现析油的现象。不同乳化顺序得到乳液的稳定性不同。乳液M-WG-XG（面筋蛋白纳米粒与玉米油乳化得粗乳液,然后加入黄原胶二次分散）的稳定性最好,同时乳液的平均粒径最小（21.4±0.314）μm。黄原胶的加入增大了乳液的净电荷,乳液的稳定性提高。共聚焦显微镜结果表明,乳液M-WG-XG液滴分布均匀,界面层呈现出多层结构。相比于其他方式制备的乳液,乳液M-WG-XG有更好的黏弹性和离子稳定性。     

Effects of xanthan gum on physicochemical properties and stability of corn oil-in-water emulsions stabilized by polyoxyethylene (20) sorbitan monooleate

The influence of added xanthan gum on rheological and dispersion characteristics and stability of concentrated (50% w/w) corn oil-in-water emulsions, stabilized with 5% (percentage on oil amount) polyoxyethylene (20) sorbitan monooleate (Tween 80), have been investigated. Emulsion with no xanthan indicated coalescence and poor creaming stability. All emulsions, with and without xanthan, showed shear-thinning flow behavior. Addition of xanthan protected emulsions from coalescence during 15 days of storage. Increase in xanthan concentration led to decrease in droplet average radius and creaming index, and increase in elastic properties of emulsions. Decrease in the emulsions flow behavior indexes, which suggested the extent of non-Newtonian behavior of emulsions, was influenced by increase in xanthan concentration. Above 0.04% of xanthan concentration, G′ and G″ values indicated formation of weak gels. Gel structure existence arises from droplet network association, due to depletion flocculation. Standard deviation of emulsions droplet size mean diameter decreased while concentration of added xanthan increased.     

Stabilization of olive oil – lemon juice emulsion with polysaccharides

An olive oil – lemon juice Greek salad dressing was developed employing xanthan gum as stabilizer and gum arabic or propylene glycol alginate as emulsifier in various combinations. In general, samples containing xanthan gum arabic were more stable against oil droplet coalescence and less stable against creaming. The use of propylene glycol alginate in the place of gum arabic, on the other hand, resulted in emulsions of higher creaming stability. Application of steady shear rheology and determination of rheological parameter values from the shearing stress-rate of shear curves, indicated that the rheological properties of the dressings were decreased with storage. Dressing texture assessment preference tests indicated that potential consumers of the product may opt for a medium viscosity product and this has to be taken into consideration when designing polysaccharide – stabilized dressings exhibiting a decrease in their textural characteristics with storage time.     

Effects of protein concentration and oil-phase volume fraction on the stability and rheology of menhaden oil-in-water emulsions stabilized by whey protein isolate with xanthan gum

The influences of protein concentration (0.2, 1, 2 wt%) and oil-phase volume fraction (5%, 20%, 40% v/v) on emulsion stability and rheological properties were investigated in whey protein isolate (WPI)-stabilized oil-in-water emulsions containing 0.2 wt% xanthan gum (XG). The data of droplet size, surface charge, creaming index, oxidative stability, and emulsion rheology were obtained. The results showed that increasing WPI concentration significantly affected droplet size, surface charge, and oxidative stability, but had little effect on creaming stability and emulsion rheology. At 0.2 wt% WPI, increasing oil-phase volume fraction greatly increased droplet size but no significant effect on surface charge. At 1 or 2 wt% WPI, increasing oil-phase volume fraction had less influence on droplet size but led to surface charge more negative. Increasing oil-phase volume fraction facilitated the inhibition of lipid oxidation. Meanwhile, oil-phase volume fraction played a dominant role in creaming stability and emulsion viscosity. The rheological data indicated the emulsions may undergo a behavior transition from an entropic polymer gel to an enthalpic particle gel when oil-phase volume fraction increased from 20% to 40% v/v.     

Effect of xanthan and guar gums on the formation and stability of soy soluble polysaccharide oil-in-water emulsions

The incorporation of relevant amounts of non-adsorbing hydrocolloids to oil-in-water (O/W) emulsions is a suitable alternative to reduce creaming. The effect of incorporating xanthan gum (XG) or guar gum (GG) in soy soluble polysaccharide (SSPS) stabilized oil-in-water (O/W) emulsions was studied. The emulsions contained 6 wt.% of SSPS, 20 wt.% Perilla seed oil (PSO), an omega-3 vegetable oil, and variable amounts of XG or GG ranging from 0.03 to 0.3 wt.%. The presence of minute amounts of XG or GG in fresh emulsions significantly decreased the emulsion droplet size (EDS) although such low concentrations did not provide enough continuous phase viscosity to arrest creaming. Emulsion microstructure indicated the presence of flocculation even at high concentrations of XG or GG caused by a depletion mechanism. All emulsions with XG or GG exhibited pseudoplastic behavior while the control emulsions showed an almost Newtonian behavior. Emulsion droplet polydispersion generally decreased with increase in the continuous phase viscosity indicating the importance of continuous phase viscosity in the dissipation of shear energy throughout the emulsion during homogenization. The characteristics of the emulsions were closely related to the rheological changes of the continuous phase.