Double Emulsions Relevant to Food Systems: Preparation,Stability, and Applications

This review describes advances in the preparation of food‐relevant double emulsions (DEs) of the water‐in‐oil‐in‐water (W/O/W) and oil‐in‐water‐in‐oil (O/W/O) types with emphasis on research published within the last decade. The information is assembled and critically evaluated according to the following aspects: the food application area, the range of encapsulated components and emulsion composition, the emulsification preparation methods, the balancing of the osmotic pressure, the stabilization by increased viscosity or gelation, the role of protein–polysaccharide interactions, and the techniques used to estimate DE yield and emulsification efficiency. Particular focus is directed toward the control of encapsulation and release behavior, including strategies that have been employed to improve the retention ability of the inner phase droplets by modifying the outer oil–water interface through mixed ingredient interactions, Pickering stabilization by particles, and biopolymer gelation. We also briefly consider the incorporation of DEs into dried microcapsules and the stability of W/O/W emulsions during eating and digestion. It would appear that 2 outstanding issues are currently preventing full realization of the potential of DEs in food applications: (i) the lack of availability of large‐scale production equipment to ensure efficient nondestructive 2nd‐stage emulsification, and (ii) the limited range of food‐grade ingredients available to successfully replace polyglycerol polyricinoleate as the primary emulsifier in W/O/W formulations.     

Fat Particle Structure and Stability of Food Emulsions

We used a nondestructive Kossel diffraction technique based on the principle of backlight scattering to characterize the structure formation in concentrated model food emulsions. We also measured the effects of temperature, shear, casein micelles and gum on the fat particle packing structure in such systems. Through this technique, we demonstrated the effects of casein micelles on the pair potential of fat particle interactions and shelf life of such systems. We carried out theoretical calculations using a statistical mechanics approach by numerically solving the Ornstein-Zernike equation with Percus-Yevick closure for a bidisperse system consisting of fat particles and micelles, and showed that the experimental results were consistent with theoretical simulations.     

Lycopene Stability in Tomato Powders

The chemical stability of lycopene in 2 commercial tomato powders was evaluated during storage. Liquid chromatography and spectral analysis were used to determine lycopene loss and the formation of cis isomers and degradation products. Tomato powder products were stored at 6 and 45 °C or under fluorescent light for up to 6 wk. Several lycopene degradation products were tentatively identified in the initial and stored powders. After 6 wk at 45 °C, 60% of the lycopene was degraded. At lower storage temperatures the losses were about 30% after 6 wk. Mechanisms of loss appear to be both isomerization and oxidation.     

Microstructure and Stability of Non-Protein Stabilized Oil-in-Water Food Emulsions Measured by Optical Methods

ABSTRACT: :
The microstructure and stability of oil-in-water emulsions, stabilized with non-protein emulsifiers (sor-bitan esters), were analyzed as a function of emulsification time, rotor speed, hydrophilic-lipophilic balance (HLB), and ionic strength. Sauter average dia (D[3,2]) were determined from micrographs. Back-scattered light data were analyzed and a method to determine creaming rates of the systems was proposed. Creaming rates showed that the relationship between emulsion stability and HLB was non-linear. Addition of NaCl raised creaming rates, resulting in decreased stability, while micrographs showed the presence of flocs. Results were discussed taking account of interactions present in the system.     

番茄红素及其制品稳定性研究进展

番茄红素是一种功能性食用色素,具有优越的生理功能。但是它不稳定,容易被氯化而影响其保健作用的发挥,文中就番茄红素及其制品的稳定性做一综述。     

食品乳化剂的应用前提

随着我国食品加工技术的不断发展,特别是消费者安全意识的不断提高,各种关于食品加工方面的法规以及监督体制也随之逐步完善。这一发展趋势对食品加工行业提出了更高的要求。安全、安心和健康已逐步成为广大消费者在购买食品时的首要考虑因素。     

番茄红素在食品加工中的降解

番茄红素在食品中的降解方式主要有热氧化降解、化学氧化降解、光氧化降解和酶促降解等。影响番茄红素降解的主要因素包括氧气、食品添加物和水分活度。     

番茄红素微胶囊的稳定性研究

研究了番茄红素微胶囊在不同时间、光、热及微波条件的稳定性,并与番茄红素纯提物和粗提物进行稳定性对照实验。结果表明,番茄红素经微胶囊化后贮藏稳定性大为改善,为番茄制品的护色与安全贮藏提供了参考和依据。     

Lipid Oxidation in Oil-in-Water Emulsions: Impact of Molecular Environment on Chemical Reactions in Heterogeneous Food Systems

The susceptibility of lipids to oxidation is a major cause of quality deterioration in food emulsions. The reaction mechanism and factors that influence oxidation are appreciably different for emulsified lipids than for bulk lipids. This article reviews the current understanding of the lipid oxidation mechanism in oil‐in‐water emulsions. It also discusses the major factors that influence the rate of lipid oxidation in emulsions, such as antioxidants, chelating agents, ingredient purity, ingredient partitioning, interfacial characteristics, droplet characteristics, and ingredient interactions. This knowledge is then used to define effective strategies for controlling lipid oxidation in food emulsions.     

饮料乳化香精的稳定性研究

本文简要介绍了乳化香精的制备技术,综述了乳化香精的稳定性问题,详细阐述了控制乳化香精稳定性的主要措施.     

番茄红素在食用调和油中的稳定性的探讨

以番茄红素保存率为稳定性指标,就贮存时间、贮存温度和光照对食用调和油中添加番茄红素的影响进行了探讨。结果表明,番茄红素的保存率随贮存时间的延长而下降;随贮存温度的升高而下降,避光贮存比光照贮存的保存率高。     

食用调和油中番茄红素的稳定性研究

以番茄红素保存率为稳定性指标，就贮存时间，贮存温度和光照对食用调和油中添加番茄红素的影响进行了探讨，结果表明，番茄红素的保存率随贮存率、贮存时间的延长而下降，随贮存温度的升高，保存率下降幅度加剧；避光贮存比光保存率高；在实验给定条件下和相同的贮存内，光照强度（１９５０lx)对番茄红素的分解作用比贮存温度更为显著。     

番茄红素提取工艺及稳定性研究

番茄红素是一种非常重要的类胡萝卜素,其优越的生理功能正日益引起人们的关注,提取方法也日趋活跃和成熟。本文研究了加碱和纤维素酶提高番茄中番茄红素提取率的工艺,确定了酶的最佳添加量、酶的最佳作用时间、最佳酶解PH值及不同防腐剂对番茄红素的影响。     

番茄红素稳定性的初步研究

近年的研究表明，番茄红素是一种具有防癌抗癌活性的类胡萝卜素。我们从番茄皮中提取出番茄红素，研究了番茄红素的稳定性。结果表明番茄红素对热、碱、氧化剂、还原剂等较稳定，但对光十分不稳定。备茄红素是一种很有应用前景的功能性天然色素。     

天然番茄红素在不同环境条件下的稳定性研究

研究了番茄中的色素--番茄红素在不同环境下的稳定性。实验结果表明:天然番茄红素对光敏感;酸性条件下(pH<6)不稳定;Fe3+、Cu2+引起番茄红素的损失较大;氧化剂、还原剂、防腐剂、糖对番茄红素的稳定性影响不显著。     

Thermal Stability of Vitamin B6 Compounds in Liquid Model Food Systems

The degradation of pyridoxine (PN), pyridoxal (PL), and pyridoxamine (PM) during thermal processing was evaluated in casein-based liquid model food systems. Limited evaluation of various potentially reactive ingredients suggested that vitamin B6 stability is not strongly a function of food system composition. Rapid interconversion of PL and PM was observed. Kinetic analysis of B6 vitamer degradation revealed approximately 2.5- to 3.5-fold greater stability of PN than the other nonphosphorylated vitamers, with activation energies of 27.3, 23.7, and 20.8 kcal/mol for the loss of total vitamin B6 after initial fortification with PN, PM, and PL, respectively. Limited studies with pyridoxal 5′-phosphate indicated that it is approximately 1.5- to 2-fold less stable than PL.     

番茄红素的生理功能及保持其稳定性方法的研究进展

番茄红素是一种天然的色素,具有多种生理活性,是目前功能食品、医药、化妆品等行业的研究热点。但由于番茄红素具有特殊的不饱和结构,稳定性较差,容易发生降解和异构化,使其在应用中受到了很大的限制。本文主要对番茄红素基本性质、生理功能及稳定性进行综述,并对如何保持番茄红素稳定性的研究提出建议,以期为番茄红素的应用提供可借鉴信息。     

秋橄榄果实中番茄红素有机溶剂的萃取及其稳定性研究

利用有机溶剂萃取秋橄榄中的番茄红素,对影响萃取的诸因素,如萃取剂的种类、料液比、萃取温度和萃取时间等进行研究,并用响应面法优化提取工艺条件;另外,还研究了温度、光照、金属离子对秋橄榄番茄红素稳定性的影响。结果表明:用丙酮作萃取剂时,秋橄榄果实中番茄红素的提取效果最佳,优化后的萃取温度为52℃,萃取时间为2.1 h,料液比为1:21(g:mL)。验证实验发现,萃取量为(218.03±9.10)μg/g鲜重,与预测值较接近。秋橄榄果实中的番茄红素在高温、阳光直照、Fe3+存在的条件下十分不稳定。     

新型番茄红素微胶囊的制备及稳定性评价

分别以菊粉、麦芽糊精、海藻糖为壁材,以包埋番茄红素的乳清分离蛋白-壳聚糖双层乳液为芯材,使用喷雾干燥法制备番茄红素微胶囊。探究不同壁材、芯壁质量比对微胶囊包埋率、微观形貌、贮藏稳定性以及在酸性饮料模拟介质中稳定性、体外模拟释放的影响,以确定最佳新型番茄红素微胶囊的制备条件。结果表明：不同微胶囊的包埋率稳定在72.97%～81.90%之间,所有样品均呈现出典型的球状结构;随着芯壁质量比的降低,微胶囊中的番茄红素在贮藏期和酸性环境下的物化稳定性均明显增加;与菊粉相比,以麦芽糊精和海藻糖为壁材的微胶囊可实现番茄红素在模拟胃肠液中的控制释放。本研究有助于进一步开发番茄红素递送载体,从而促进其产业化应用。