米糠蛋白O/W及W/O/W乳液制备及界面稳定性

为对比不同米糠蛋白质量浓度下O/W及W/O/W乳液的稳定性,以米糠蛋白作为基料,采用双乳化法制备O/W及W/O/W乳液,考察不同米糠蛋白质量浓度下乳液的微观形态和稳定性并探究其界面稳定机理。结果表明：W/O/W乳液的贮存稳定性显著优于O/W乳液;与相同蛋白含量的O/W乳液相比,W/O/W乳液的黏度显著提高;当米糠蛋白质量浓度为0.4 g/100 mL时,W/O/W乳液的稳定性较O/W乳液提高了1 倍以上;乳液内部包裹更多的W/O液滴,W/O/W乳液的粒径较大;而此时静电斥力也较大,起到稳定乳液的目的。同时,米糠蛋白质量浓度不小于0.4 g/100 mL时,O/W及W/O/W乳液中蛋白质的吸附率较高,达到78%以上。本研究为天然米糠蛋白质在食品级乳液中的开发提供参考,为粮食副产物的综合利用提供了新思路。     

Water/Oil Emulsions Prepared by the Membrane Emulsification Method and Their Stability

We developed and tested a simple method to measure dispersed droplet size of W/O emulsions. Then, using a microporous glass membrane treated with oil phase, we produced a W/O emulsion with high water content (40% w/w) at a high emulsification rate by the membrane emulsification method, and assessed its stability. In comparison with emulsions by the stirring methods, variations in dispersed droplet size and viscosity of emulsions by membrane method were small and the emulsions were more stable. Droplet size was not related to the stability of the W/O emulsion prepared by membrane emulsification.     

Production of O/W Emulsions Containing Astaxanthin by Repeated Premix Membrane Emulsification

ABSTRACT: Oil-in-Water (O/W) emulsions are mainly produced by application of high mechanical stress or by membrane emulsification processes at low pressures. Advantages such as narrower droplet size distribution and lower operating costs make membrane emulsification processes more suitable for producing astaxanthin-loaded O/W emulsions. The characteristics of 1 of these membrane emulsification methods, called repeated premix membrane emulsification, are studied in this work. In this emulsification process, a pre-emulsion is repeatedly pushed through a hydrophilic or hydrophobic membrane. In this research, ahydrophilic membrane was used because the objective was to obtain an O/W emulsion. Pre-emulsions were produced by dispersing palm oil containing dissolved astaxanthin in water. The oil droplets were stabilized with a combination of 2 emulsifiers. Each O /W emulsion passed the membrane 3 times underpressures and disperse phase fractions of 5 to 15 bar and from 10 wt% to 40 wt%, respectively. To investigate the production of O/W emulsions by repeated premix membrane emulsification, mean Sauter diameters and fluxes were measured. To find the optimal ranges of pressure and dispersed phase fraction, a "2-level factorial design with central composite and stars points" experimental design was applied.     

Fish Oil Microcapsules from O/W Emulsions Produced by Premix Membrane Emulsification

Fish oil microcapsules were prepared by combining a low-energy emulsification method (premix membrane emulsification) with spray drying. Oil-in-water (O/W) emulsions were prepared using a two-step emulsification method that used a rotor–stator homogenizer followed by membrane emulsification. The influence of the emulsification method (mechanical stirring or membrane emulsification), the emulsification conditions (membrane and emulsifier type), and the amount of wall material on the physicochemical characteristics of the microcapsules was studied. The results show that the emulsification method and the type and amount of emulsifier and wall material affect the final amount of encapsulated oil. Microcapsules produced by membrane emulsification and stabilized with 2 % Tween-20 or 10 % whey protein presented the highest values (higher than 50 %) of oil encapsulation efficiency (OEE). It has been found that the OEE increases when decreasing the droplet size of the emulsions as well as with the increase of the amount of wall material employed during drying. Morphology analysis showed that the microcapsules obtained from O/W emulsions produced by premix membrane emulsification were rounder in shape, without visible cracks on the surface and no vacuoles on the inside. Oxidation stability tests performed on some selected samples indicate that the microcapsules with higher stability are the ones produced with a higher amount of wall material and have less surface oil.     

提高W/O/W多重乳状液的稳定性研究

研究了W／O／W多重乳状液稳定性的影响因素。实验表明，W／O／W多重乳状液制备的较佳工艺操作条件为乳化温度40℃，pH值2．5，W／O／W搅拌时间25min，第一相体积比0．48，第二相体积比0．66。     

壳聚糖W/O型乳状液的超声辅助制备及其稳定性

以非牛顿假塑性大分子壳聚糖溶液为水相,棕榈油为油相,Span-80为乳化剂,采用单因素试验及响应面试验优化超声协助制备W/O型乳液工艺,并考察优化条件下制备的乳液稳定性.结果表明:内水相含量是影响乳液粒度大小的关键因素,且超声功率对乳液的粒度及其分布存在过处理现象.优化工艺为超声功率300 W、超声时间15 min、内...     

亲脂性乳化剂的性质和用量对W/O/W型复合乳状液稳定性的影响

研究了亲脂性表面活性剂的性质和用量对W/O/W型复合乳状液稳定性的影响,采用两种类型的亲脂性表面活性剂：新型的聚合型高分子表面活性剂聚氧乙烯（30）二聚羟基硬脂酸脂（Arlacel P135）和传统的小分子表面活性剂Span80和Tween80的混合物（质量比9∶1,HLB=5.4）制备复乳。采用离心保留率、光学显微镜和黏度等方法评价初乳和复乳的稳定性。结果表明,与小分子表面活性剂Span80和Tween80的混合物相比,大分子聚合表面活性剂Arlacel P135可以显著地提高复合乳状液的稳定性,在优化的条件下复乳的稳定性可以达到2000r/min离心15min不分层。     

第二步乳化工艺参数对W／O／W型复乳稳定性和胰岛素包埋率的影响

研究了用两步乳化法制备W/O/W型复乳时,第二步乳化的乳化工艺参数对复乳的稳定性和药物包埋率的影响规律.以胰岛素为模型药物,用两步乳化法制备W/O/W型复乳,用离心后的乳层保留率评价复乳的稳定性,用高效液相法测定胰岛素在复乳中的包埋率,用激光光散射法测定复乳的粒度分布.实验结果表明,随着第二步乳化过程中乳化强度的提高,复乳滴的粒径减小,复乳的离心稳定性提高而胰岛素包埋率降低.胰岛素包埋率与复乳的粒度分布的关系分为两个区域:当乳化强度较小时,复乳滴的粒径较大,比表面积较小,胰岛素包埋率与体积平均粒径成正比;当乳化强度增大时,复乳滴粒径减小,比表面积增大,胰岛素包埋率与比表面积成反比.在本研究中使胰岛素包埋率最高的第二步乳化过程工艺参数为:VirTishear高速分散均质机分散速度2 000 r/min,分散时间3 min,此工艺下胰岛素的包埋率达到55%.     

Effect of Propylene Glycol Alginate and Xanthan Gum on Stability of O/W Emulsions

The role of xanthan gum and propylene glycol alginate in stabilizing model oil-in-water salad dressing emulsions has been studied using rheological measurements, particle size analysis and surface tension. Increasing xanthan gum concentration within the gum ratio gave higher viscosity due to formation of aggregates with larger sizes. Propylene glycol alginate (PGA) was surface-active leading to reduction in surface tension of air/water surfaces. Reduction in viscosity was seen in the presence of PGA.     

油/水型乳状液中的油相结晶

报道了油相在高度分散状态下的结晶特性 .应用超声波检测技术分别研究了降温和升温过程中体积分数为 2 0 %的O/W型乳状液中油相 (正十六烷 )粒子 (平均直径d32 =0 .3 6± 0 .0 2 μm)内部晶体的形成和熔化、在结晶点的晶体生长情况以及在高于结晶温度的情况下结晶粒子对未结晶粒子的诱导结晶等 .结果表明 ,与体相结晶相比 ,分散相的结晶需要更深的过冷程度 (数值取决于乳化剂类型和粒子大小 ) ;在结晶温度下 ,粒子内晶体的成核和生长过程与粒子间的相互作用关系不大 ;油相成分相同时 ,结晶了的粒子会诱使未结晶的粒子发生固化 .在乳状液体系中 ,完全液态的粒子的成核被认为是一种均相成核 ,而液固态粒子共存的体系的结晶有可能遵循一种异相成核机理 .     

不同极性抗氧化剂对油包水乳液氧化稳定性的影响

以富含多不饱和脂肪酸(UPFA)的核桃油为油相,采用超高压微射流均质机制备油包水(W/O)乳液,分别添加非极性抗氧化剂α-生育酚及其极性对应物—6-羟基-2,5,7,8-四甲基色烷-2-羧酸(Trolox)于乳液中,45℃避光保存,检测乳液初级氧化产物—脂质氢过氧化物与次级氧化产物-顶空己醛含量,探究抗氧化剂极性对W/O乳液稳定性影响。结果表明,10~1000μM,α-生育酚与Trolox对W/O乳液脂质氢过氧化物和己醛的形成都具有抑制作用,其中Trolox抗氧化性随浓度的增大而提升,而较高浓度的α-生育酚(500~1000μM)反而降低其对脂质氢过氧化物的抑制作用;α-生育酚分布于乳液油水界面浓度小于极性抗氧化剂Trolox,导致非极性抗氧化剂α-生育酚活性低于极性抗氧化剂Trolox;乳液水相pH 3.0时,Trolox抗氧化性高于水相pH 7.0,水相pH通过影响Trolox在W/O乳液各相分布,从而影响其抗氧化性。     

紫苏子油O/W型纳米微乳的制备及其氧化稳定性

紫苏子油是一种天然的营养保健品,可作为食品补充剂使用.紫苏子油不溶于水,将其掺入水性介质中相当困难,致使生物利用度较低.本研究以表面活性剂的亲水、亲油值(HLB)为指导,制备复合表面活性剂,并结合伪三元相图,利用转相乳化法制备纳米微乳.通过优化工艺参数以形成稳定的紫苏子油纳米微乳,并评估其稳定性.紫苏子油纳米微乳的最优...     

Dispersion Stability of O/W Emulsions with Different Oil Contents Under Various Freezing and Thawing Conditions

Freezing and thawing of oil‐in‐water (O/W) emulsion‐type foods bring about oil–water separation and deterioration; hence, the effects of freezing and thawing conditions on the destabilization of O/W emulsions were examined. The freezing rate and thawing temperature hardly affected the stability of the O/W emulsion. O/W emulsions having different oil fractions were stored at temperatures ranging from –30 to –20 °C and then thawed. The stability after thawing depended on the storage temperature, irrespective of the oil fraction of the emulsion. A good correlation was found between the time at which the stability began to decrease and the time taken for the oil to crystalize. These results indicated that the dominant cause for the destabilization of the O/W emulsion during freezing and thawing is the crystallization of the oil phase and that the effects of the freezing and thawing rates on the stability are insignificant.     

黄原胶对O/W乳状液稳定性的影响

报道了含有黄原胶的２０Ｏ／Ｗ乳状液贮藏在２７～３０℃的分层动力学的研究。实验运用超声波技术考察了从０．０００５～０．５ｗｔ％的一系列浓度的黄原胶对体系分层特性的影响。在非常低（＜０．００１ｗｔ％）的黄原胶浓度下，实验体系的稳定性变化不大。０．０１～０．０２ｗｔ％的黄原胶可引起样品底部富水层出现，但体系无明显分层。当黄原胶浓度增加到０．０２ｗｔ％以上，乳状液很快分层，且分层的状态取决于黄原胶添加量。只有当添加量超过０．２５ｗｔ％，黄原胶才能起到提高体系稳定性的作用。对非吸附性的黄原胶的这种影响，可以用“排除絮凝”和弱凝胶结构形成的机理进行解释。     

黄原胶的热处理对乳浊液分层特性的影响

通过对 2 0 %油 /水乳浊液分层特性的测定 ,讨论了加热处理对黄原胶稳定乳浊液的性能的影响 .黄原胶水溶液预先被加热到一定的温度 ,然后再加入到乳浊液体系 ,结果发现 ,加热后的黄原胶能在更宽的浓度范围内引起乳浊液分层 .加热到 90℃的样品 ,欲实现完全的稳定效果 ,黄原胶的用量相对于未经加热的样品要加倍 ;即使在 90℃下只热了 7min ,0 .3 %的黄原胶也会导致体系发生分层 ,而且受热时间越长 ,引起的分层越严重 .黄原胶的这种性质被归结为在热处理中分子的构象从有序的螺旋状缔合态转变成了无序的、依据受热时间不同而解聚程度不同的线团状 ,因而改变了体系的流变学性质和黄原胶导致的‘排除’作用力的大小 ,结果改变了乳浊液的分层性质 .     

基于内源乳化法和喷雾干燥优化制备花色苷微胶囊及其稳定性分析

以海藻酸钠为壁材,基于内源乳化法制备微胶囊化的湿态花色苷,经优化喷雾干燥条件制备花色苷微胶囊,考察花色苷微胶囊粒径和形态及微胶囊化前后花色苷的光照、温度及胃肠消化稳定性。花色苷微胶囊喷雾干燥的最佳工艺条件为加热器温度120℃、进料速率12 r/min、真空压力0.03 MPa,包埋率为75.12%,平均粒径为558.2 nm。光照5 h,花色苷和花色苷微胶囊保存率分别为63.7%、82.1%;避光5 h,花色苷和花色苷微胶囊保存率分别为78.6%、91.4%;90℃条件下,花色苷和花色苷微胶囊半衰期分别为2.54、6.39 h;2 h胃消化,花色苷和花色苷微胶囊保存率分别为45.3%、83.7%;4 h肠消化,花色苷和花色苷微胶囊保存率分别为0.9%、24.4%。研究结果表明内源乳化法结合喷雾干燥制备的花色苷微胶囊的光照、温度以及胃肠消化稳定性均高于花色苷。     

酒精对酪蛋白酸钠溶液及O/W乳状液的影响

介绍了酒精对酪蛋白酸钠溶液及酪蛋白稳定的O/W乳状液性质的影响 .试验表明酒精在一定程度上可以降低酪蛋白酸钠的溶解度 .界面张力的测定则表明酒精的存在在很大程度上可以降低油—水界面和油—酪蛋白溶液界面的界面张力 .含酒精的乳状液体系的粘度会由于酒精的存在而提高 ,在酒精体积分数达 3 0 %时 ,乳状液体系的粘度会突然大幅度升高 .通过O/W乳状液的分层稳定性测定可发现 ,低浓度的酒精可以提高酪蛋白稳定的乳状液的分层稳定性 ,但酒精质体积分数超过 3 2 %时 ,乳状液的分层稳定性会受到破坏 .含酒精的O/W乳状液体系中油相含量的提高在一定范围内可以提高乳状液的稳定性 ,但高分散相浓度的含酒精的乳状液体系中由于连续相中酒精浓度的提高使乳状液体系稳定性下降 .