乳化剂在烘焙食品中的应用

本文简要介绍了乳化剂在面包、蛋糕、饼干等烘焙食品中所起的作用,应用种类、应用方式,以及使用时应注意的问题.指出:乳化剂除具有典型的表面活性作用外,还能与食品中的碳水化合物、蛋白质、脂类等发生特殊的相互作用而发挥多种功效.其具体应用品种和用量比例要综合考虑生产配方、工艺、设备的实际情况,以及产品的品质要求、经济指标和食品安全等来决定.     

The determination of viable counts in probiotic cultures microencapsulated by spray-coating

An assessment of various methods to determine viable counts (CFU) in freeze-dried and dried microencapsulated (ME) probiotic cultures was carried out. Microencapsulation was done by spray-coating of dried Lactobacillus rhamnosus R0011 or Bifidobacterium longum ATCC 15708 cultures with fat. Rehydration of the ME powders was incomplete when they were added to water and gently agitated. As a result analytical methods based on vortexing of rehydrated ME cultures and which did not incorporate a high-shear homogenization (HSH) step underestimated the viable counts. The CFU of ME cultures were identical when methods using either blender or generator probes high-shear homogenization (HSH) were carried out. Furthermore HSH reduced the variability of the CFU results of both free-cell and ME cultures by a factor of three. The addition of an emulsifier (Tween 80) in the rehydrating medium to dissolve fat did not improve CFU counts when generator probes were used for HSH. The presence of fat in the ME product, or when added to the rehydration medium, improved CFU counts of B. longum but not of L. rhamnosus.     

可聚合非离子乳化剂对丙烯酸酯乳液性能的影响

采用半连续聚合工艺,使用可聚合非离子乳化剂烯丙氧基壬基酚聚氧乙烯(10)醚(ANPEO10)制备了聚丙烯酸酯乳液,讨论了不同乳化剂用量对乳液性能的影响,并用常规非离子乳化剂壬基酚聚氧乙烯(10)醚(OP-10)作对比。结果表明:ANPEO10乳化体系比OP-10乳化体系的反应活化能小、粒径大、粘度变化幅度大;用可聚合乳化剂ANPEO10提高了乳胶膜的耐水性和耐溶剂性。     

Interfacial tension kinetics of nisin and β-Casein at an oil-water interface

The concentration- and time-dependence of interfacial pressure of nisin and β-casein at ann-hexadecane-water interface were evaluated by using DuNoüy tensiometry. The two emulsifiers attained interfacial saturation at a bulk concentration of about 0.1 mg/ml, the reduction of the interfacial tension by nisin at that concenration being about equivalent to that of β -casein. The time dependence of interfacial tension recorded for each protein was described by using two kinetic models. In the first, the reduction of interfacial tension with time was considered to be a result of molecular penetration into the interface followed by rearrangement. Nisin exhibited more rapid penetration and rearrangement at the interface than did β -casein. In the second, the model allowed for the parallel, irreversible adsorption of protein into each of two states from solution, where state 2 molecules occupy greater interfacial area and are more tightly bound than state 1 molecules. The extent of adsorption in state 1 and state 2 was determined to be highly concentration dependent for each protein; adsorption occurs mostly in state 1 at high concentration and mostly in state 2 at low concentrations.     

乳化剂与石料配套数据库研究概述

根据稀浆封层施工中石料与乳化剂配伍性不好的问题，设计合成五个系列乳化剂，建立石料与乳化剥配套数据库，以解决稀浆封层质量问题，并适当降低工程造价。     

Impact of emulsifier microenvironments on acid–base equilibrium and activity of antioxidants

Mechanisms by which emulsifiers influence the activity of antioxidants in emulsions were investigated. To evaluate the importance of the partitioning between the different phases, the proportions of ferulic acid (FA) and isoferulic acid (iFA) at the o/w interface, in the coexisting micellar phase and in the aqueous phase were experimentally determined. An increase of the total emulsifier concentration and hence the micellar concentration led to an increased solubilisation of FA and iFA by the emulsifier pseudophases. From the point of view that the solubilisation sites of the antioxidants have different properties and thereby affect their activity, the microenvironment of each antioxidant was characterised in terms of local pH values and electrostatic potential. The degree of dissociation of both FA and iFA decreased in the order CTAB > SDS ≈ Brij. Information about the relative locations of the antioxidants was deduced from the extents to which the dissociation equilibria were affected by their environment. It was concluded that (1) the proximity to the polar headgroup of SDS, (2) a high degree of dissociation in a CTAB environment and (3) a deeper intercalation into the headgroup region of Brij were favourable for the antioxidant activity.     

BA—MMA系共聚乳液胶粘剂──加料方式和乳化剂配比对性能的影响

采用不同的加料方式和不同的阴离子型、非离子型乳化剂配比，制备了以丙烯酸丁酯和甲基丙烯酸甲酯为主体的丙烯酸酯共聚乳液胶粘剂，经测试，结果表明，在批量法、全连续法和半连续法几种加料方式中，批量法丙烯酸酯乳液膜的强度最大；随离子型乳化剂或非离子型乳化剂含量的减少，BA—MMA共聚乳液的表面张力下降，剥离强度增加。     

乳化剂造成丁苯橡胶乳液聚合反应下降原因分析

乳化剂在丁苯橡胶低温乳液生产过程中起到至关重要的作用,它是保证聚合反应平稳进行的重要因素之一,其组成体系的参数波动会对聚合反应结果造成较大的影响,使得聚合反应胶乳的TSC和门尼值发生波动,甚至造成生产事故。对由乳化剂pH值和TSC波动造成聚合反应下降的原因做了分析。     

油酸-2-羟基-3-(三乙基氯化铵)丙基酯的合成及性能评价

用油酸和三乙胺中和成盐,再与环氧氯丙烷进行酯化,合成了一种新的阳离子表面活性剂油酸-2-羟基-3-(三乙基氯化铵)丙基酯,测定了其表面张力和临界胶束浓度。用该乳化剂对道路沥青进行了乳化效果考察,表明该乳化剂乳化性能良好。谈乳化剂合成工艺简单, 是一种比较有发展前途的阳离子沥青乳化剂。     

花生乳的稳定性及乳化稳定剂的研究

本文研究了不同HLB(亲水亲油平衡值)的乳化剂与M-H复合乳化剂对花生乳的稳定效果。研究表明,花生乳的HLB值是影响稳定的主要因素。花生乳的粘度与稳定性无正比关系。本文还就复合乳化剂的稳定性机理进行分析,并提出了以离心测试模拟自然沉降研究花生乳稳定性的新方法。