大豆分离蛋白乳状液稳定性的几种分析方法比较

用不同质量分数(0.5%、1%、2%、3%)的大豆分离蛋白(SPI)和大豆油制备3%O/W型乳状液,比较不同离心力作用下和添加不同量SPI乳状液稳定性的差异以及添加不同量SPI乳状液黏度的差异,考察贮存期延长过程中的浊度法测定乳状液稳定性以及乳状液粒径和Zeta电位的变化,结合外观和微观观察,寻找一种快速准确测定乳状液稳定性的方法。结果表明:离心法、贮存期浊度法与乳状液外观观察的结论一致,都表明添加3%SPI的乳状液最稳定,并且SPI添加量越高,乳状液黏度越大,稳定性越好。储存期乳状液平均粒径和Zeta电位发生变化,但难以作为乳状液稳定性的判断标准。本实验进一步验证,离心法能够快速、准确地预测乳状液的稳定性,适于产品开发和成品检验的需要。     

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.     

Effect of Heating and Homogenization on the Stability of Coconut Milk Emulsions

: The effects of homogenization and heat treatment on the colloidal stability of coconut milk were studied. Fresh coconut milk (15% to 17% fat, 1.5% to 2% protein) was extracted and stored at 30 °C before homogenization at 40/4 MPa (stage I/stage II). Both homogenized and non‐homogenized samples were heated at 50 °C, 60 °C, 70 °C, 80 °C, and 90 °C for 1 h. Homogenization reduced the size of the primary emulsion droplets from 10.9 to 3.0 μm, but increased the degree of flocculation, presumably via a bridging mechanism. This flocculation was also responsible for increased viscosity of the homogenized samples. Heating increased the degree of flocculation in both non‐homogenized and homogenized samples. A slight amount of coalescence was also observed after heating above 80 °C. All samples creamed after 24 h of storage, but the heated samples formed a larger cream layer, presumably because the flocculated droplets packed together less efficiently. Optical microscopy was used to confirm the combination of flocculation and creaming responsible for changes in coconut milk quality. The information obtained from this study provides a better understanding of the emulsion science important in controlling coconut milk functionality.     

二十二碳六烯酸微藻油乳状液稳定性的测定方法和影响因素

以二十二碳六烯酸（docosahexaenoic acid,DHA）微藻油微胶囊化过程中形成的乳状液为研究对象,探究乳状液稳定性的测定方法和影响因素。通过比较3 种不同乳状液稳定性测定方法以及显微镜观察发现：采用0.1 g/100 mL十二烷基硫酸钠溶液对乳状液进行稀释,检测乳状液形成24 h在600 nm波长处透光率的变化可以方便、准确地衡量其稳定性。壁材组成、芯材比例和总固形物质量分数都能够明显影响乳状液稳定性,从而影响微胶囊产品品质。当壁材中辛烯基琥珀酸酯化淀粉与麦芽糊精的质量比在2∶3、DHA微藻油质量分数在20%、总固形物质量分数在33%以下时,制备得到的DHA微胶囊产品的品质较高,且能够满足SC/T 3505—2006《鱼油微胶囊》规定。微胶囊化后DHA微藻油的贮存稳定期得到明显延长。     

不同乳化剂对油酸和亚油酸乳状液稳定性的影响

本文以粒径、稳定性和流变为考察指标,利用激光粒度仪、食品稳定性分析仪、流变仪等研究不同种类和添加量的食品乳化剂(阿拉伯胶、酪蛋白酸钠、吐温20)对不饱和脂肪酸(油酸和亚油酸)乳状液的制备及其稳定性的影响。结果表明,三种乳化剂均可制备出稳定性较好的乳状液,不同乳化剂的质量分数不同得到乳状液的稳定性不同。较高质量分数的阿拉伯胶(4%,w/v)乳状液,具有最低的澄清指数并且具有最大粘度(0.30~0.40 Pa·s)。当酪蛋白酸钠的质量分数为2%时,制备出的乳状液较稳定,但粒径较大,贮藏稳定性较差。较低质量分数的吐温20(1%,w/v)的乳状液具有最小粒径(0.20~0.21 μm),经过贮藏后变化程度也最小。本文研究了不同食品乳化剂制备的不饱和脂肪酸乳状液及其稳定性,可为不饱和脂肪酸乳状液的制备和应用提供参考。     

不同蛋白稳定乳液的冻融稳定性

本文以1%m/V浓度的大豆分离蛋白和乳清浓缩蛋白为材料,对蛋白热处理形成颗粒后制备油分数为0.4的水包油型Pickering乳液,未加热处理的蛋白和酪蛋白酸钠稳定乳液作为对照。将不同蛋白稳定的乳液在-20℃冷冻24 h随后在30℃恒温箱解冻3 h,如此冷冻-解冻处理循环三次,探讨未加热处理的活性蛋白和热诱导形成的蛋白颗粒稳定乳液的冻融稳定性,包括新鲜制备和每次冻融之后乳液的乳滴粒径分布、聚结和絮凝程度、乳液分层和脂肪上浮情况、以及乳液的光学显微结构。结果表明冷冻乳液融化时不可避免的被部分破坏,而大豆分离蛋白热诱导聚集颗粒稳定的Pickering乳液具有优良的冻融稳定性,这可能为一些水包油乳液型冷冻食品、热敏性生物活性物质和低温储存药品的制备和研发提供一条有效的技术途径。     

蛋黄蛋白-植酸静电复合物对蛋黄乳液物理稳定性的影响

为改善蛋黄（egg yolk,EY）在酸性乳液体系的物理稳定性,采用EY蛋白与植酸（phytic acid,PA）形成静电复合物稳定EY乳液。研究酸性条件下PA质量分数（0%～0.8%）对EY蛋白及EY乳液物理稳定性的影响。结果表明,pH 3.0时,EY与0.012 5%～0.8% PA形成不溶性的静电复合物EY-PA;最优质量分数（0.2%）PA与含1%蛋白的EY形成复合物制备乳液较对照组的乳液黏度升高,粒径及乳析指数显著降低（P＜0.05）,界面蛋白质吸附量显著提高（P＜0.05）,乳滴分布更均匀,乳液的抗聚结效果提高。因此,EY蛋白与PA形成的静电复合物可调控EY乳液的理化特性,提高EY在酸性乳液体系的物理稳定性。     

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.     

植物蛋白饮料稳定性及其测定方法综述

植物蛋白饮料关键的质量问题是产品的稳定性,本文综述了影响饮料稳定性的因素及常用的提高稳定性的方法,重点叙述了生产和研究人员常用的稳定性的测定方法。     

Evaluation of Process Parameters in the O/W/O Multiple Emulsion Method for Flavor Encapsulation

ABSTRACT: The multiple emulsion/cold dehydration method was developed for the flavor encapsulation. The effects of various process parameters on the emulsion stability and flavor retention were investigated. Microfluidizer (at 68 MPa) produced more stable emulsion with small uniform droplets than pressure-homogenizer. Increasing the gum arabic content created a highly viscous emulsion, which resulted in a stable O/W emulsion. The stability of an O/W/O multiple emulsion was highly affected by the type of emulsifiers and the most stable emulsion was prepared using the blend of Span 80 and PGPR. Well-formed microcapsules having high flavor retention (71%) was obtained when ethanol/water mixture solution of 9:1 was used as a dehydrating agent.     

基于大豆酶解聚集体制备Pickering乳液凝胶及环境稳定性分析

以大豆酶解聚集体（insoluble soy peptide aggregate,ISPA）制备Pickering乳液凝胶,在探索ISPA制备高油相乳液性质的基础上,对比分析模拟环境对乳液凝胶性质与稳定性的影响。结果表明：随着ISPA质量分数和油相体积分数增加,乳液粒径减小,凝胶强度增强,且以质量分数1.00%的ISPA和体积分数60%的油相制备的乳液展现出较强凝胶潜能;随后,将上述乳液凝胶置于不同NaCl浓度或酸性pH值下,发现乳液凝胶强度在高浓度NaCl或低pH值下仍有所增强,且经90 d常温贮藏或90 ℃加热60 min后粒径变化较小。综上,ISPA在新型Pickering稳定剂和食品配料开发中具有较大的加工应用潜能。     

Rancimat法与Schaal烘箱法测定花生油和花生酱氧化稳定性的对比

分别采用Rancimat法与Schaal烘箱法测定花生油和花生酱的氧化稳定性,并对2种方法的相关性进行了分析。结果表明:用Rancimat法替代传统的过氧化值测定法评价花生油和花生酱的氧化稳定性是可行的。     

一种控制粘胶针织物尺寸稳定性能的方法

本文针对粘胶针织物的尺寸稳定性能进行了研究,在分析织物尺寸稳定性能影响因素的基础上,介绍了研究策略和具体的研究方法,并通过实验进行了验证。     

Stability of Anthocyanin‐Rich W/O/W‐Emulsions Designed for Intestinal Release in Gastrointestinal Environment

Abstract: Anthocyanins belong to the most important hydrophilic plant pigments. Outside their natural environment, these molecules are extremely unstable. Encapsulating them in submicron‐sized containers is one possibility to stabilize them for the use in bioactivity studies or functional foods. The containers have to be designed for a target release in the human gastrointestinal system. In this contribution, an anthocyanin‐rich bilberry extract was encapsulated in the inner aqueous phase of water‐in‐oil‐in‐water‐double emulsions. The physical stability as well as the release of free fatty acids and encapsulated, bioactive substances from the emulsions during an in vitro gastrointestinal passage were investigated. The focus was on the influence of emulsion microstructural parameters (for example, inner and outer droplet size, disperse phase content) and required additives (emulsifier systems), respectively. It could be shown that it is possible to stabilize anthocyanins in the inner phase of double emulsions. The release rate of free fatty acids during incubation was independent of the emulsifier used. However, the exterior (O/W)‐emulsifier has an impact on the stability of multiple emulsions in gastrointestinal environment and, thus, the location of release. Long‐chained emulsifiers like whey proteins are most suitable to transport a maximum amount of bioactive substances to the effective location, being the small intestine for anthocyanins. In addition, it was shown that the dominating release mechanism for entrapped matter was coalescence of the interior W₁‐droplets with the surrounding W₂‐phase. Practical Application: Microencapsulation of phytochemicals and bioactives is in the focus of functional food development. Here, the influence of matrix material, formulation, and structural parameters on stabilization and release of the molecules encapsulated has to be known for target product and process design. As the results are representative for hydrophilic active ingredients encapsulated in double emulsion systems a cross‐sectoral use in the pharmaceutical sector is possible.     

基于粒子特性研究特殊医学用途配方食品全营养乳液的稳定性

本文基于乳液粒子微观特性（平均粒径、电位、离心沉淀率等）考察不同稳定剂、体系pH以及贮存时间对全营养乳液体系稳定性的影响。结果显示不同的胶体对全营养乳液的粒子特性影响不同。微晶纤维素对全营养乳液体系的平均粒径、黏度的影响不大,微晶纤维素最适宜浓度为0.6 g/L。结冷胶浓度与全营养乳液的平均粒径成反比,与粘度成正比,结冷胶最适宜浓度为0.1 g/L。胶体浓度（结冷胶和微晶纤维素）对于全营养乳液的电位影响不明显。采用杀菌釜灭菌时,pH为6.68时全营养乳液平均粒径最小,离心沉淀率为1.79%,体系比较稳定。常温货架期实验显示全营养乳液平均粒径、电位、pH变化主要在货架期前60 d发生,乳液中粒子等特性变化到一定的程度,进而影响到全营养乳液的稳定性。货架期105 d以后,全营养乳液粒子特性基本维持不变。     

The Peroxide Challenge Test: A Novel Method for Holistic Near‐Real Time Measurement of Beer Flavour Stability

A holistic approach is paramount to reliably measure beer staling. As a consequence, the peroxide challenge test (PCT) was developed as an alternative to electron spin resonance (ESR). The principle of the PCT is to mimic oxidation by titrating beer with hydrogen peroxide. The more hydrogen peroxide a beer can quench, the more resistant it is against oxidation and flavour deterioration. The PCT allows cost effective, near real time, high throughput assessment of beer flavour stability. The PCT is convenient and inexpensive to perform and the results correlate with ESR measurements and the perceived aged character of beer.     

The Possibilities of Particle Analysis Demonstrated by the Measurement of the Colloidal Stability of Filtered Beer

Long‐term stability is one of the most important quality criteria of beer. Three groups of measuring methods are available for its determination: real time tests, predictive tests and indicative tests. One of the most common methods is the predictive forcing test, which is a time‐consuming method for accelerating beer ageing, e.g., at 0°C and 60°C. Two ways exist to perform this test: (1) follow‐up of haze development and determination of the lag phase or (2) the measurement of haze values after several days. The first option was evaluated by performing a long‐term Forcing test over a period of 4 months by analyzing a bottom‐fermented beer. It was shown that the haze curve followed a typical course with a lag phase, an increase phase and a stationary phase. Significant differences between the measurement after the cooling and the warm period were shown. In search of quicker methods and more accurate predictive indicators, the charge titration method was developed as an alternative to determine the particle charge of filtered beers, whereupon the relationship was elucidated between the increase in hazing and decrease of potential along with the advanced aging of beer. The results showed that with increased particle size due to agglomeration, the total charge decreased. In this array of trials, two differently stabilized beers were examined. Although both beers showed different haze values in the beginning (0.32 EBC and 1.30 EBC), the less stabilized beer had only 10 warm days and in contrast the beer with the good stabilization had over 20 warm days. With the help of the total charge, predictions were possible regarding the long‐term stability of the beer.     

会东蔗区甘蔗新品种的丰产性、稳产性分析

采用回归系数(b)和离回归均方(S^2d)等稳定性参数,对引进会东糖厂的Q75等5个甘蔗新品种以及川蔗13号等两个当地主栽品种的丰产性、稳产性进行了分析。结果表明,075、粤糖86—368、粤农81-762和川蔗13号等4个品种平均产量较高,稳产性较好,可以在会东糖厂蔗区加速繁殖推广。进一步对参试品种的产量构成因子如株高、茎径、有效茎的变异系数进行分析表明,各参试品种甘蔗产量的稳定性是建立在产量构成因子稳定性及其合理组合基础之上的。     

预测葡萄酒酒石酸氢钾稳定性的新方法

酒石酸氢钾(KHT)是影响葡萄酒稳定性的重要因素,其溶解度决定于温度、酒度、pH值。当温度低于饱和温度时酒石酸盐就不会析出,产生沉积物。白葡萄酒的TSAT<9℃;红葡萄酒的TSAT<16℃;桃红葡萄酒的TSAT<11℃。(孙悟)     

彩喷纸涂料的稳定性研究

从胶体化学理论出发,利用高分子溶液对溶胶的保护作用,往涂料体系中加入自制的聚丙烯酰胺,来控制低固含量彩喷纸涂料中胶粒的团聚。系统考察了保护剂聚丙烯酰胺的分子量,胶黏剂聚乙烯醇(PVA)的型号,以及两者与阳离子添加剂、聚乙烯蜡乳液助剂等的加入量对涂料体系稳定性的影响。通过单因素实验和正交试验确定了最佳的低固含量涂料配方为:硅溶胶(固含量30%)100g,聚丙烯酰胺(分子量1.11×104)0.6g,聚乙烯醇(型号PVA235)3g,固色剂(型号IJ-450,固含量30%)30g,聚乙烯蜡乳液(固含量35%)0.7g。