A Comparison of the Stability of Beverage Cloud Emulsions Formulated with Different Gum Acacia- and Starch-Based Emulsifiers

Abstract: The performance of several hydrocolloids (3 gum acacias, 1 modified gum acacia, and 3 modified starches) in stabilizing beverage emulsions and corresponding model beverages was investigated employing different core materials, emulsifier usage levels, and storage temperatures. Concentrated emulsions were prepared using orange terpenes or Miglyol^® 812 (comprising medium-chain triglycerides, MCT) weighted 1:1 with ester gum, stored at 25 or 35 °C, and analyzed on days 0, 1, and 3. On day 3, model beverages were made from each emulsion, stored at both temperatures, and analyzed weekly for 4 wk. Stability of concentrated emulsions was assessed by measuring mean particle size and by visual observations of ringing; beverage stability was judged similarly and also by loss of turbidity. Particle size measurements showed concentrated emulsions containing gum acacia or modified gum acacia with either core material were stable over 3 d storage at both temperatures whereas those made with modified starches were not, destabilization being faster at 35 °C. Beverages based on orange terpenes, in contrast to Miglyol, yielded smaller mean particle sizes, both on manufacture and during storage, regardless of hydrocolloid used. Visual observations of ringing generally supported this finding. Modified gum acacia was evaluated at both recommended and higher usage levels, stability increasing in the latter case. In general, all gum acacia and modified gum acacia emulsifiers were superior in stability to those based on modified starches, at either temperature, for orange terpene-based beverages. In Miglyol-based beverages, similar results were seen, except 1 modified starch performed as well as the gum acacia products.     

辛烯基琥珀酸-阿拉伯胶酯的合成工艺及乳化性能

以阿拉伯胶(gum arabic,GA)和辛烯基琥珀酸酐(octenyl succinic anhydride,OSA)为原料,采用湿法制备辛烯基琥珀酸-阿拉伯胶酯(octenyl succinic acid-GA ester,OS-GA)。通过单因素试验和响应面分析研究OS-GA的合成工艺,并对其产物乳化性能进行了研究。结果表明:OS-GA合成的较优组合为OSA添加量3.0%(以干基GA计)、GA溶液初始质量浓度40 g/100 m L、反应体系pH 8.85、反应温度33℃、反应时间130 min。在此工艺条件下制备的OS-GA的辛烯基琥珀酸接入量为1.99%,其乳化能力及乳化稳定性均显著提高。     

亚麻籽胶的乳化性质

重点研究了亚麻籽胶的乳化性质，实验结果表明。亚麻籽胶的质量分数、溶解温度、乳化温度、加油量以度贮存温度等对亚麻籽胶的乳化性质都有影响。质量分数增加，亚麻籽胶的乳化稳定性增强；加油量增多。亚麻籽胶的乳化稳定性下降；溶解温度升高能提高亚麻籽胶的乳化稳定性；而乳化温度和贮存温度越高，亚麻籽胶乳状液越不稳定。由于亚麻籽胶与阿拉伯胶在相对分子质量、均方旋转半径、粘度、疏水性氨基酸含量上的差异，导致了亚麻籽胶与阿拉伯胶乳化性质的差异．     

阿拉伯胶乳液对共轭亚油酸的氧化保护和在模拟胃肠液中的释放研究

共轭亚油酸(CLA)是一类具有多种生理活性的不饱和脂肪酸,极易被氧化,在食品工业中的应用受到很大限制。本文采用阿拉伯胶(GA)制备CLA乳液,从CLA氧化产物角度来评价GA对CLA乳液的氧化保护作用,同时对CLA在模拟胃肠中的释放动力学特征进行研究。结果表明,5.0%浓度时GA在乳液界面荷载量达到最大,此浓度下乳液中CLA的挥发性氧化降解产物浓度最低,氧化稳定性最好;在模拟胃液中释放率缓慢增加,粒径分布均匀;在模拟肠液中释放率加快,乳液出现大颗粒聚集。随着GA浓度增加,CLA挥发性氧化降解产物含量增加,氧化稳定性降低;CLA在胃部释放率有所增加,大颗粒聚集增多。但总体来说,GA乳液中CLA在模拟胃肠液中的释放显示出了良好的营养缓释性能,延长了CLA的释放时间,提高了CLA的生物利用度。     

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。     

Rheological Properties and Emulsifying Activity of Gum Karaya (Sterculia Urens) in Aqueous System and Oil in Water Emulsion: Heat Treatment and Microwave Modification

Gum karaya is a polysaccharide gum from Sterculia urens tree. It is used as an emulsifier and thickening agent in cosmetics and pharmaceuticals. However, it has very strong swelling properties, high viscosity, and low solubility, providing the restricted applications in the food industry. The main objective of this study was to investigate the effects of different heat treatment and microwave variables (i.e., time: 8, 10, and 12 min; power: 700 and 1000 W) on the functional properties of gum karaya in the aqueous system and oil-in-water emulsion. In this regard, the rheological properties, emulsifying activity, average droplet size, and surface morphology of the native- and microwave-treated gums were analyzed and compared. Dynamic oscillatory test indicated that the microwave-treated gum karaya had more gel-like behavior than viscous-like behavior (G′ > G″) at a relatively high concentration (20% or 20 g/100 g). When gum karaya was treated by microwave for 8–12 min, both elastic (G′) and viscous (G″) moduli were declined. The native- and microwave-treated gum karaya exhibited a shear-thinning (pseudoplastic) behavior in the aqueous system and oil-in-water emulsion. The results showed that the microwave-treated gum karaya had smaller particles than the native gum in the aqueous system. On the other hand, the emulsion containing the microwave-treated gum karaya had finer emulsion droplets than the control containing the native gum karaya. This confirmed that the application of microwave treatment led to significantly (p < 0.05) improve the emulsifying activity of gum karaya.     

静电溶吹制备明胶/玉米醇溶蛋白/百里香酚纳米纤维及其表征

玉米醇溶蛋白（Zein）因其独特的自组装特性被广泛应用于食品功能性组分的荷载与递送。但由于其疏水性强,单一Zein基Pickering乳液的界面稳定性难以满足实际应用的需要,采用合适的多糖构建复合体系是改善其乳液稳定性的有效策略。本文采用复凝聚法制备了不同蛋白-多糖比例的假酸浆子胶（NPG）与Zein复合颗粒（NZPs）,对其理化性质、结构及乳液特性进行了表征。结果表明,当NPG比例越大时,NZPs的表面润湿性越强,同时蛋白和多糖在静电作用力下形成的复合颗粒粒径尺寸越小且趋于均匀分布。NZPs的内源荧光光谱中对应特征峰的峰强分别与Zein和NPG的含量呈正比,NPG的复合影响了Zein中酪氨酸残基所处微环境的极性。傅里叶红外光谱（FT-IR）中峰位的移动以及新峰的生成表明蛋白-多糖中存在氢键作用以及新的化学键生成。NZPs基Pickering乳液的储能模量（G'）大于损耗模量（G\     

Evaluation of extrusion-modified fenugreek gum

The present study was carried out to investigate the molecular mass distribution, hydration, and emulsifying properties of extrusion-modified fenugreek gum. Fenugreek gum was extruded in a twin-screw extruder with four different zone 5 barrel temperatures (105, 120, 135, and 150 °C). To minimize the reduction in molecular weight of fenugreek gum during the extrusion process, an exit die was not used. High performance size exclusion chromatography revealed that extrusion cooking slightly changed the molecular mass distribution of the gum. Hydration properties of the gum, such as water dispersibility, water solubility, water hydration viscosity, and water absorption rate, were significantly improved after extrusion cooking. The results suggested that extrusion processing of fenugreek gum could lead to some changes in the structure and functional groups, including disruption of the cell-wall structures and unfolding of the polysaccharide molecules, which could lead to the exposure of functional groups, such as hydrophilic groups, from inside, thereby improving the hydration properties. However, the extrusion process did not significantly affect the water holding capacity of the gum, nor significantly influence the emulsion capacity and stability of the gum. On the other hand, the extrusion process did noticeably remove the unpleasant flavor associated with the original fenugreek gum.     

Effect of medium molecular weight xanthan gum in rheology and stability of oil‐in‐water emulsion stabilized with legume proteins

Xanthan gum is a water‐soluble extracellular polysaccharide that has gained widespread commercial use because of its strong pseudoplasticity and tolerance to high ionic strength, which bring unique rheological properties to solutions. This study compares and evaluates the emulsifying properties of oil‐in‐water (30:70 v/v) emulsions stabilized with lupin and soya protein isolates and medium molecular weight xanthan gum. The protein was obtained by an isoelectric precipitation method and the polysaccharide was produced by Xanthomonas campestris ATCC 1395 in batch culture in a laboratory fermenter (LBG medium) without pH control. The addition of xanthan gum in the emulsion formulation enhances emulsion stability through the phenomenon of thermodynamic incompatibility with the legume protein, resulting in an increase of the adsorbed protein at the interface. The emulsion stability is also enhanced by a network structure built by the polysaccharide in the bulk phase. Copyright © 2005 Society of Chemical Industry     

不同NaCl浓度条件下亚麻籽胶对肌原纤维蛋白凝胶作用力及乳化特性的影响

为改善低盐肉制品凝胶乳化品质的降低,明确亚麻籽胶（flaxseed gum,FG）添加对肉制品品质的影响,以肌原纤维蛋白（myofibrillar protein,MP）为研究对象,通过测定乳析指数、电位值、粒径、显微观察研究不同NaCl浓度条件下FG对MP乳液乳化稳定性的影响,而化学键的测定显示FG对MP凝胶化学作用力的影响。结果表明,形成MP凝胶及FG-MP凝胶体系的关键是二硫键和非二硫共价键的贡献;不同NaCl浓度对FG-MP乳液的乳析指数、ζ-电位、粒径的影响均不显著（P＞0.05）,而MP乳液随着NaCl浓度的提高,乳化稳定性、ζ-电位、粒径均显著变化（P＜0.05）。特别是在低浓度NaCl条件下,FG的加入可以显著提高MP乳液的稳定性（P＜0.05）。显微观察发现加入FG可以改善MP乳液液滴聚集的现象。因此,说明在低浓度NaCl条件下加入FG可以显著提高肌原纤维蛋白乳液的乳化稳定性,提高其抗盐能力,促进亚麻籽在肉制品中的应用。     

低粘度辛烯基琥珀酸淀粉酯作微胶囊壁材的研究

本文测定了低粘度辛烯基琥珀酸淀粉酯和阿拉伯树胶的粘度,并分别采用低粘度的辛烯基琥珀酸淀粉酯和阿拉伯树胶作色拉油微胶囊体系的壁材,测定了乳状液的乳化稳定性和产品的微胶囊包埋率及贮存稳定性。研究结果表明:低粘度辛烯基琥珀酸淀粉酯粘度比阿拉伯树胶低;以低粘度辛烯基琥珀酸淀粉酯为壁材的微胶囊的包埋效果效率、贮藏稳定性优于阿拉伯树胶,且随取代度的增加低粘度辛烯基琥珀酸淀粉酯为壁材制成的微胶囊的贮存稳定性也增加。     

不同NaCl浓度条件下亚麻籽胶对肉糜乳化凝胶特性的影响

通过对出水出油率、质构、扫描电镜、脂肪微粒表面蛋白量以及蛋白电泳的测定和观察,研究不同NaCl浓度条件下亚麻籽胶对肉糜乳化凝胶特性的影响。研究发现,NaCl浓度的降低（0.6～0?mol/L）会增加肉糜的出水出油率,质构变差,减少脂肪微粒表面蛋白含量。而亚麻籽胶的添加可以显著增强凝胶的保水、保油性（P＜0.05）,改善凝胶的网络结构,并且还会提高脂肪微粒表面蛋白的种类和数量,提高乳化稳定性（P＜0.05）。由此可见,低NaCl浓度（0～0.4?mol/L）会造成乳化肉制品品质劣变,亚麻籽胶的加入可以改善低NaCl浓度造成的品质降低。     

单月桂酸甘油酯接枝改性阿拉伯胶及其乳化性能

采用单月桂酸甘油酯（glyceryl monolaurate,GML）对其接枝改性,并对比探讨不同投料比（GML/阿拉伯胶（gum arabic,GA）=0%、5%、10%、20%）条件下,所得改性产物（GML-GA）的乳化性能和对油水乳液稳定性的影响。研究发现,改性并未改变溶液牛顿流体的本体流变学性质,但改性产物（GML-GA）的乳化性能和对油水乳液的稳定性显著提高。改性产物的乳化性随投料比增加呈现先提高而后略有下降的趋势,其中GML/GA投料比为10%的改性产物乳化性能最高。由于GML可能主要被接枝于GA中的高含量组分阿拉伯半乳聚糖（arabinogalactan,AG）分子上,因此相比于乳化性能仅源于阿拉伯半乳聚糖蛋白（arabinogalactan protein,AGP）组分贡献的GA,改性产物GML-GA乳化能力的提高则源于AGP和改性AG双组分的贡献。     

Characterization of the influence of main emulsion components on the physicochemical properties of orange beverage emulsion using response surface methodology

The present work was conducted to investigate the influence of main emulsion components, namely Arabic gum (7–13% w/w), xanthan gum (0.1–0.3% w/w) and orange oil (6–10% w/w) contents on physical stability, viscosity, cloudiness and conductivity of orange beverage emulsion. In this study, 20 orange beverage emulsions were established based on a three-factor central composite design (CCD) involving 8 factorial points, 6 axial points and 6 center points. The main objective of the present study was to determine an optimal concentration level of main emulsion components leading to an optimum orange beverage emulsion with desirable physicochemical properties. In general, all response surface models were significantly (p<0.05) fitted for describing the variability of physical stability, viscosity, conductivity and cloudiness as a nonlinear function of the content of main emulsion components. More than 84% of the variation of physicochemical properties of orange beverage emulsion could be explained as a function of the content of the main beverage emulsion components. In general, the orange oil content appeared to be the most significant (p<0.05) factor influencing all emulsion characteristics studied except for conductivity. From the optimization procedure, the overall optimal region leading to the desirable orange beverage emulsion was predicted to be achieved by the combined level of 13% (w/w) Arabic gum, 0.22% (w/w) xanthan gum and 10% (w/w) orange oil.     

The effect of addition of flaxseed gum on the emulsion properties of soybean protein isolate (SPI)

The effect of addition of flaxseed gum on the emulsion properties of soybean protein isolate (SPI) were investigated in this study. Flaxseed gum with 0.05-0.5% (w/v) concentration was used together with 1% (w/v) SPI to emulsify 10% (v/v) soybean oil. The emulsion was analyzed for emulsion activity (turbidity), stability, particle size, surface charge, and rheological properties. The turbidity and absolute zeta-potential values decreased initially by the addition of flaxseed gum and subsequently increased with further increase in the gum concentration to reach their peak around 0.35% (w/v) gum. The particle size of the emulsion decreased and reached a minimum value at 0.1% (w/v) gum concentration. Any increase in gum concentration beyond this value resulted into increase in the particle size. This study would help to widen the application of SPI and flaxseed gum mixture, and also contribute to the understanding of protein-gum interaction in emulsion.     

维药阿拉伯胶重金属含量测定及安全性评价

目的测定阿拉伯胶中常见重金属铅、镉、铜、砷、汞的含量,评价其安全性,为建立阿拉伯胶重金属检测限值提供参考。方法用原子吸收法测定铅、镉、铜、砷、汞的含量,以《药用植物及制剂外经贸绿色行业标准》为标准评价阿拉伯胶的安全性。结果所测各批次样品铅、镉、铜、砷、汞的含量相差较小,符合《药用植物及制剂外经贸绿色行业标准》。结论可安全用于临床,为保障临床用药安全提供依据。     

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。     

Study of emulsions stabilized with Phaseolus vulgaris or Phaseolus coccineus with the addition of Arabic gum, locust bean gum and xanthan gum

The properties of o/w emulsions stabilized with 1%w/v common bean (Phaseolus vulgaris L.), V or scarlet runner bean (P. coccineus L.), Coc extracted by isoelectric precipitation or ultrafiltration, at pH 7.0 and 5.5, with the addition of Arabic gum, locust bean gum, xanthan gum and a mixture of xanthan gum–locust bean gum (0.1 %w/v and 0.25 %w/v) are studied. The stability of emulsions was evaluated on the basis of oil droplet size, creaming, viscosity and protein adsorption measurements. The addition of Arabic gum, caused an increase in D[4,3] values and a decrease in the amount of protein adsorbed at the interface. The addition of locust bean gum in some emulsions reduced the amount of protein adsorbed. The addition of xanthan and to a less extend of the polysaccharide mixture, promoted a decrease in D[4,3]. So, emulsion stability was affected by the polysaccharide nature. Differences were also observed with respect to the protein nature, the method of its preparation and emulsion's pH. All polysaccharides enhanced the emulsions viscosity with xanthan and xanthan–locust bean gum exhibiting the higher values. V isolates and isoelectricaly precipitated isolates of both V, Coc showed higher viscosity values. The stability was enhanced by the increase of the viscosity of the continuous phase and the creation of a network, which prevents the oil droplets from coalescence.     

乳清分离蛋白/阿拉伯胶复合物纳米颗粒制备及其pH稳定性

本实验对乳清分离蛋白(WPI)和阿拉伯胶(GA)分子内复合物进行热处理,旨在固化WPI/GA,使其形成稳定的纳米复合物颗粒并研究其pH稳定性。结果表明,当WPI/GA混合物浓度为1%,85℃加热15 min,可形成稳定分散的纳米复合物颗粒,并呈现出良好的pH稳定性。WPI/GA纳米复合物颗粒具有良好的乳化活性,1%浓度下的纳米复合物颗粒可制备含20%中链甘油三酯(MCT)的分散均一的水包油型乳液。结论:通过对WPI/GA分子内复合物进行热处理,使蛋白在聚集过程中与GA缠绕,形成稳定的WPI/GA纳米复合物颗粒,改善了WPI/GA分子内复合物的pH敏感性。并呈现出良好的乳化活性,为其作为纳米载体荷载功能因子方面的应用提供了很好的前景。     

乳清分离蛋白-阿拉伯胶复合体系制备的共轭亚油酸粉末油脂的理化特性及稳定性

本实验采用乳化活性优异的乳清分离蛋白(WPI)和阿拉伯胶(GA)分子内复合物为乳化剂,通过高压均质制备稳定的共轭亚油酸(CLA)乳液,并对乳液粒径和稳定性进行了评价。利用喷雾干燥法制备CLA粉末油脂,研究了进风口温度和CLA浓度对粉末油脂包封率的影响,并对CLA粉末油脂的复溶稳定性、机械性能和氧化稳定性进行了评价。结果表明,当复合乳化剂浓度为2%,进风口温度为130 ℃,CLA浓度为15%~25%时,包封率大于90%,粉末油脂分散均匀、复溶性好、法向应力Fn达到最大、耗氧速率0.005 μmoL/(mL·min)明显低于其他浓度下的0.01 μmoL/(mL·min)。通过乳化活性优异的WPI-GA分子内复合物制备出稳定的共轭亚油酸粉末油脂,提高了其稳定性,扩大了功能因子共轭亚油酸的应用范围。