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.     

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 .     

淀粉微粒和酪蛋白酸钠协同稳定Pickering乳状液性质

制备淀粉微粒和酪蛋白酸钠协同稳定的Pickering乳状液。以流体动力学直径、Zeta电位、界面张力、粒度、界面蛋白浓度、脂肪部分聚结率、流变性和光学显微镜观察为指标,研究淀粉微粒质量浓度变化对Pickering乳状液性质的影响。结果表明,淀粉微粒质量浓度变化显著影响协同体系流体动力学直径、Zeta电位和界面张力。当淀粉微粒质量浓度为0.04 g/100 mL时,其与酪蛋白酸钠协同稳定的Pickering乳状液表现剪切稀释特性,乳状液表面积平均直径和体积平均直径最小,分别为3.50μm和1.97μm;界面蛋白浓度和脂肪部分聚结率最高,分别为3.90 mg/m2和7.98%;分散相脂肪球直径最小,为4.11μm,表明淀粉微粒在一定质量浓度范围内对酪蛋白酸钠的界面活性起到促进作用,两者能够共同维持Pickering乳状液稳定。     

紫苏籽油乳状液的制备及其稳定性评价

将富含α-亚麻酸的紫苏籽油制备成水包油型(O/W)乳状液后,其稳定性、水溶性得到改善,并可作为ω-3多不饱和脂肪酸的传递系统,应用于功能食品的开发。分别采用阿拉伯胶、HI-CAP 100、纯胶2 000、可溶性大豆多糖、酪蛋白酸钠和大豆分离蛋白制备紫苏籽油乳状液,研究乳化剂对乳状液粒径、黏度及物理稳定性的影响。结果显示:4%阿拉伯胶制备的乳状液粒径最小(0.678μm),粒径主要分布在0.1~10μm之间,随着乳化剂浓度的增大,乳状液的黏度不断升高,且不稳定性指数和Slope值逐渐降低,其中,除HI-CAP 100和酪蛋白酸钠外,乳化剂质量分数≥4%时,乳状液稳定性良好。     

酪蛋白酸钠-明胶制备S/O/W乳状液的稳定性

碳酸钙是一种常用的强化钙,然而,其悬浮稳定性差,易产生沉淀,严重限制了碳酸钙在食品加工中的应用.以固/油/水(S/O/W)乳状液形式负载碳酸钙,构建具有特定结构分布的钙-脂质微球,有望改善其溶解性和稳定性.本文以食品级碳酸钙为S相,大豆油为O相,酪蛋白酸钠-明胶为W相,构建S/O/W钙-脂质微球,研究不同质量分数明胶和...     

乳状液胶体颗粒界面结构设计研究进展

乳状液是一种以水包油(oil in water,O/W)和油包水(water in oil,W/O)形式稳定分散相的功能因子传递体系。通过对乳状液油-水两相界面进行一定的微结构设计,可以在改善乳状液物理稳定性的同时,提升分散相包封功能因子的化学稳定性。本文综述了目前在乳状液中具有应用前景的4种胶体颗粒界面结构设计(复合界面结构设计、多层界面结构设计、颗粒界面结构设计、综合界面结构设计)及其在乳状液中的应用,为未来通过改变胶体颗粒界面组成和结构而获得具有特定理化性质和功能的结构化乳状液提供参考。     

焙烤脱模油油包水型乳状液稳定性探讨

脱模油是焙烤食品工业重要的加工助剂,它的组成是典型的油包水型乳状液体系,油包水型乳状液稳定理论的研究对脱模油的配方和制作具有重要的指导意义。本文探讨了影响油包水乳状液稳定性的因素,控制乳状液稳定性的方法在于降低体系界面张力、提高界面膜的强度及体系的粘度,介绍了脱模油的制作方法与品质测定方法。     

处理和添加物对O/W型乳化体系稳定性的影响

O/W型乳化体系在食品工业中的应用非常广泛,传统的O/W型乳化体系是由两种互不相溶的液体(水相和油相)通过混合或者均质而制备的。然而,在O/W型乳状液食品加工贮藏过程中,会产生絮凝、分层和氧化酸败等品质劣变从而影响整个体系的稳定性。因此,在乳化体系的制备过程中需要通过降低界面张力、增加油滴间的分子斥力和添加抗氧化剂防止氧化等方式来获得良好的稳定性。该文主要综述了不同的处理方法(p H值、离子强度、热处理、超高压均质化等)和外源添加物(多糖、蛋白水解物等)对O/W型乳化体系的物理稳定性和氧化稳定性的影响,从而为提高乳状液类型食品的品质奠定良好的理论参考。     

基于微粒乳化技术的松香乳状液的制备

研究了阳离子型共聚有机微粒对松香溶液／水体系的乳化与稳定作用。结果发现,微粒乳化剂可将松香溶液／水体系乳化成O／W型松香乳状液。随着松香溶液体积分数和微粒乳化剂用量的增加,乳状液稳定性提高,黏度也随之变化。初始油水体积比例为1：1时,加入质量分数为3％的微粒乳化剂,便可得到稳定的松香乳液。     

乳状液成分对O/W乳状液性质的影响

采用单因素实验设计,通过机械搅拌方法制备O/W乳状液。通过乳状液的离心稳定性、粘度和乳状液的显微结构,研究不同HLB值的复合乳化剂及含量、脱脂乳粉溶液的浓度以及油和水比例对乳状液性质的影响,最终确定较佳的乳状液成分。实验结果表明:当以Span-80和Tween-80为复合乳化剂,其HLB值为9.6、复合乳化剂含量为16%(w/w)、脱脂乳粉溶液浓度为25%(w/v)、油与水比为1∶1(w/w)时,可以获得状态较好的乳状液,此时乳状液的离心稳定性最高,可以达到97.5%。     

STABILITY OF OIL-IN-WATER EMULSIONS. 2. Effects of Oil Phase Volume, Stability Test, Viscosity, Type of Oil and Protein Additive

SUMMARY –Stability of oil-in-water emulsions stabilized in sodium caseinate, gelatin and soy sodium proteinate was found to be increased by either an increase in the aqueous phase protein concentration (0.5–2.5%) or oil phase volume (20–50%). Both factors were significantly interrelated. Emulsions stabilized by soy sodium proteinate were generally higher in stability as compared to those stabilized by gelatin or sodium caseinate. With emulsions containing gelatin, greater stability occurred when the stability testing temperature was increased from 37–70°C and when the time interval was decreased from 24 hr to 90 min. Maximum relative viscosities of emulsions stabilized by gelatin and sodium caseinate were 2.0 and 2.5, respectively. Emulsions stabilized by soy sodium proteinate were quite viscous, with relative viscosity from 1.5–30 depending on both protein concentration and oil phase volume. Interchanging the emulsified oil among corn, soybean, safflower and peanut oils did not alter emulsion stability when examined at three concentrations of soy sodium proteinate. Changing the oil to olive oil significantly increased emulsion stability at each soy sodium proteinate level with oil phase volumes of 30, 40 and 50%.     

Interfacial composition and stability of emulsions made with mixtures of commercial sodium caseinate and whey protein concentrate

The interfacial composition and the stability of oil-in-water emulsion droplets (30% soya oil, pH 7.0) made with mixtures of sodium caseinate and whey protein concentrate (WPC) (1:1 by protein weight) at various total protein concentrations were examined. The average volume-surface diameter (d₃₂) and the total surface protein concentration of emulsion droplets were similar to those of emulsions made with both sodium caseinate alone and WPC alone. Whey proteins were adsorbed in preference to caseins at low protein concentrations (<3%), whereas caseins were adsorbed in preference to whey proteins at high protein concentrations. The creaming stability of the emulsions decreased markedly as the total protein concentration of the system was increased above 2% (sodium caseinate >1%). This was attributed to depletion flocculation caused by the sodium caseinate in these emulsions. Whey proteins did not retard this instability in the emulsions made with mixtures of sodium caseinate and WPC.     

蛋白界面膜及其评价方法研究进展

食品中乳化类产品的稳定性决定了其价值和顾客满意度,天然蛋白的乳化特性多年来受到食品胶体和界面科学领域广泛关注。蛋白吸附到水油界面形成的黏弹性薄膜具有降低界面张力、维持乳液稳定的特性。研究蛋白界面膜的物化性质有助于了解蛋白大分子在水油界面的吸附规律,能够用于评价、表征和预测蛋白乳液稳定性,并为优化蛋白乳液稳定性提供理论基础。基于此,该文对水包油乳液蛋白界面膜结构和影响因素进行探讨,系统综述了目前用于评价蛋白质界面特性的手段和方法,包括微观成像技术、热力学技术、光谱技术和界面流变学技术等,以研究蛋白类乳化液性能在宏观和微观层面的联系,为蛋白质界面膜在乳化食品中的应用提供参考。     

一种水包油包胶型乳液的制备及其在乳化肠中的应用

以结冷胶和无水氯化钙为内水相凝固剂,酪蛋白酸钠为外水相乳化剂,制备一种水包油包胶（S/O/W）型 乳液。以多重乳液粒径和分布为指标,研究酪蛋白酸钠添加量对S/O/W型多重乳液加工适应性的影响。结果表明： 正交试验得到S/O型单重乳液最佳制备条件为：内水相中结冷胶添加量0.2%、无水氯化钙添加量0.5%;内水相乳化 剂聚甘油蓖麻醇酯添加量2.5%;油相为精炼猪油,油水体积比3∶2;剪切速率17 500 r/min,剪切时间1.5 min。将制 得的S/O型单重乳液与不同添加量酪蛋白酸钠混合制得S/O/W型多重乳液。当酪蛋白酸钠添加量0.1%时,S/O/W型 多重乳液粒径符合加工要求,且贮藏、热处理、剪切稳定性较好。以多重乳液替代猪脂肪制备的低脂乳化肠与高脂 （精炼猪油含量20%）乳化肠外观不存在明显差异;微观结构观察结果表明,多重乳液在乳化肠中包裹良好、分布 均匀。     

Interactions at the interface between hydrophobic and hydrophilic emulsifiers: Polyglycerol polyricinoleate (PGPR) and milk proteins,studied by drop shape tensiometry

The equilibrium interfacial tension and dilational elasticity at the soy oil–water interface were studied in the presence of a lipophilic emulsifier, polyglycerol polyricinoleate (PGPR), in the continuous oil phase, and dairy proteins, β-lactoglobulin (β-lg) or sodium caseinate, in the aqueous phase using drop shape tensiometry. The interfacial tension decreased with increasing PGPR concentration, and was <2 mN m⁻¹ at PGPR concentrations beyond 1%. The presence of proteins in the water phase, β-lg and sodium caseinate, further reduced the interfacial tension. Even at the low concentrations (0.008%) tested, PGPR dominated the interfacial elasticity, which was only slightly affected by the addition of elevated levels of protein. While in the presence of β-lg (0.1%) in isolation, the system showed a high interfacial elasticity, the addition of PGPR lowered the elasticity, suggesting that PGPR interfered with protein–protein interactions at the interface, or caused displacement of β-lg. Interfacial elasticity at the oil–water interface showed little dependence on dilation or frequency of the sinusoidal oscillation, when the interface was dominated by PGPR.     

Effect of a new emulsifier containing sodium stearoyl-2-lactylate and carrageenan on the functionality of meat emulsion systems

The emulsion capacity and stability of a new emulsifier containing sodium stearoyl lactylate plus iota carrageenan (SSL/iC) in comparison to caseinate and soy isolate was analysed. The emulsion capacity and stability of SSL/iC in oil/water (O/W) model system emulsions was higher than shown by caseinate and soy isolate. However, the O/W emulsion stability was negatively affected by sodium chloride addition, but positively affected by an increase in temperature. Meat batters were made with caseinate, soy isolate, and SSL/iC at the minimum concentration that showed a good performance (>75% stability) in the O/W emulsions. The emulsifier SSL/iC produced high cook yields and good stability when used in meat batters. However, the cooked meat batters containing SSL/iC showed texture characteristics highly detrimental to the sensory analysis. On the other hand, the addition of 2% potato starch reduced the differences in texture parameters among the samples made with the different emulsifiers.     

Effect of Aqueous Phase Composition on Stability of Sodium Caseinate/Sunflower oil Emulsions

The aim of the present work was to investigate the effect of aqueous phase composition on the stability of emulsions formulated with 10 wt% sunflower oil as fat phase. Aqueous phase was formulated with 0.5, 2, or 5 wt% sodium caseinate, or sodium caseinate with the addition of two different hydrocolloids, xanthan gum or locust bean gum, both at 0.3 or 0.5 wt% level or sodium caseinate or with addition of 20 wt% sucrose. Emulsions were processed by Ultra-Turrax and then further homogenized by ultrasound. Creaming and flocculation kinetics were quantified by analyzing the samples with a Turbiscan MA 2000. Emulsions were also analyzed for particle size distribution, microstructure, viscosity, and dynamic surface properties. The most stable systems of all selected in the present work were the 0.3 or 0.5 wt% XG or 0.5 wt% LBG/0.5 wt% NaCas coarse emulsion and the 20 wt% sucrose/5 wt% NaCas fine emulsion. Surprisingly, coarse emulsions with the lower concentration of NaCas, which had greater D _4,3, were more stable than fine emulsions when the aqueous phase contained XG or LBG. In these conditions, the overall effect was less negative bulk interactions between hydrocolloids and sodium caseinate, which led to stability. Sugar interacted in a positive way, both in bulk and at the interface sites, producing more stable systems for small-droplet high-protein-concentration emulsions. This study shows the relevance of components interactions in microstructure and stability of caseinate emulsions.     

Effects of pre‐emulsifying fat/oil on meat batter stability,texture and microstructure

The effects of pre‐emulsified beef fat and canola oil (CO) (25%) with Tween 80 (T‐80) or sodium caseinate (SC) were studied in beef meat batters prepared at three protein levels (9%, 12% and 15%). Raising meat protein level to 15% resulted in low emulsion stability of products prepared with CO. Using pre‐emulsified beef fat with Tween 80 (BF‐T80) showed significantly higher fat and water losses at all protein levels. There were no differences in fat and water losses between pre‐emulsified beef fat and CO when SC was used at the 9% and 12% protein levels compared to the controls (non pre‐emulsification). Light microscopy revealed fat globule coalescence in the CO meat batters prepared with 15% protein and BF‐T8 treatments, as well as formation of fat channels and more protein aggregation; both resulted in lower emulsion stability. Using SC to emulsify fat/oil produced a finer dispersion of fat globules compared to all the other treatments.     

Oil-in-Water Emulsions Stabilized by Sodium Caseinate or Whey Protein Isolate as influenced by Glycerol Monostearate

Competitive adsorption between glycerol monostearate (GMS) and whey protein isolate (WPI) or sodium caseinate was studied in oil-in-water emulsions (20 wt % soya oil, deionized water, pH 7). Addition of GMS resulted in partial displacement of WPI or sodium caseinate from the emulsion interface. SDS-PAGE showed that GMS altered the adsorbed layer composition in sodium caseinate stabilized emulsions containing < 1.0 wt % protein. Predominance of β-casein at the interface in the absence of surfactant was reduced in the presence of GMS. The distribution of α-lactalbumin and β-lactoglobulin between the aqueous bulk phase and the fat surface in emulsions stabilized with WPI was independent of the concentration of added protein or surfactant.     

Effect of high-methoxy pectin on properties of casein-stabilized emulsions

We report on the effect of high-methoxy pectin on the stability and rheological properties of fine sunflower oil-in-water emulsions prepared with α_s1-casein, β-casein or sodium caseinate. The aqueous phase was buffered at pH 7.0 or 5.5 and the ionic strength was adjusted with sodium chloride in the range 0.01–0.2 M. Average emulsion droplet sizes were found to be slightly larger at the lower pH and/or with pectin present during emulsification. Analysis of the serum phase after centrifugation indicated that some pectin becomes incorporated into the interfacial layer at pH 5.5 but not at pH 7.0. This was also supported by electrophoretic mobility measurements on protein-coated emulsion droplets and surface shear viscometry of adsorbed layers at the planar oil–water interface. A low pectin concentration (0.1 wt%) was found to give rapid serum separation of moderately dilute emulsions (11 vol% oil, 0.6 wt% protein) and highly pseudoplastic rheological behaviour of concentrated emulsions (40 vol% oil, 2 wt% protein). We attribute this to reversible depletion flocculation of protein-coated droplets by non-adsorbed pectin. At ionic strength below 0.1 M, the initial average droplet sizes, the creaming behaviour, and the rheology were found to be similar for emulsions made with either of the individual caseins (α_s1 and β) or with sodium caseinate. At higher ionic strength, however, whereas emulsions containing β-casein or sodium caseinate were stable, the corresponding α_s1-casein emulsions exhibited irreversible salt-induced flocculation which was not inhibited by the presence of the pectin.