Emulsion Formation and Stability
Emulsion Formation and Stability
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乳液的形成和稳定性
DOI：
10.1002/9783527647941.ch4
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Niknafs N
中科院分区：
文献类型：
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作者：
Niknafs N
许多天然和加工食品都是以乳状液为基础的，了解和控制它们的功能需要了解乳状液的形成、稳定性、储存以及这些系统如何在消费时分解。控制乳状液的液滴大小是实现特定功能的手段之一；液滴大小影响乳状液的重要性质，如稳定性、颜色和保质期[1]。最终的平均乳滴尺寸是乳化过程中同时发生的液滴破碎和合并两个子过程之间动态平衡的结果。尽管已有研究，但对乳状液在加工过程中的物理行为仍然缺乏了解，这主要是因为缺乏实时监测乳化机理的直接测量技术。在典型的乳化过程中，在稳态条件下，液滴的大小是液滴破碎和合并之间动态平衡的结果。然而，乳化早期阶段的子过程的时间尺度明显较短。因此，任何过程的液滴尺寸和液滴尺寸分布都会经历快速变化，这就需要稳健的测量技术。表4.1概述了为乳化实验研究开发的测量技术。这些技术通常可以分为三类：监测液滴尺寸的技术，专注于液滴破碎的技术，以及单独考虑合并的技术。有几种技术可以利用乳化实验获得的样品离线测量液滴尺寸。样品测量的可靠性取决于样品在取样后和测量前的稳定性。因此，当需要对在自然条件下不稳定的样品进行精确测量时，这往往是一个问题。为了克服这个问题，在取样后，在溶液中加入大量的稳定剂，以确保在测量之前液滴大小不会发生变化。然而，不仅可以从采样到相加的时间
A wide range of natural and processed foods are emulsion based, and understanding and controlling their functionality requires knowledge of emulsion formation, stability, storage, and how these systems break down on consumption. Controlling the droplet size of the emulsion is one of the means to induce particular functionalities; droplet size influences important emulsion properties, such as stability, color, and shelf life [1]. The final average emulsion droplet size is the result of the dynamic balance between the two subprocesses of droplet breakup and coalescence, which occur simultaneously during emulsification. Despite previous studies, a lack of understanding of the physical behavior of emulsions during processing remains, mostly because of the lack of direct measurement techniques for monitoring the mechanism of emulsification in real time. In a typical emulsification process, under steady state conditions the droplet size would be the result of the dynamic balance between droplet breakup and coalescence. However, the time scales of the subprocesses in the early stages of emulsification are significantly short. Thus, droplet sizes and droplet size distributions of any process undergo rapid variations, which create a necessity for robust measurement techniques. An overview of the measurement techniques developed for experimental studies of emulsification is shown in Table 4.1. These techniques can generally be divided into three categories: those monitoring droplet size, those that concentrate on droplet breakup, and those that consider coalescence individually.Several techniques exist for offline measurement of droplet size using samples obtained from emulsification experiments. The reliability of the measurements of the samples depends on the stability of the samples after sampling and before the measurement. Therefore, it is often a problem when precise measurements are required with samples that are not stable under natural conditions. In order to overcome this problem, after sampling, a large amount of stabilizer is added to the solution in order to ensure that the droplet size will not change until the time of the measurement. However, not only may the time from sampling until the addition