Classification and characteristics of emulsifiers

Sep 13,2023

Emulsifier is a commonly used food additive in our lives, what are the emulsifiers? Classification and selection of emulsifiers? You can understand these problems with the editor.

First, what are the emulsifiers

1. Negative ion emulsifier

Emulsifiers for ionizing negative ionic hydrophilic groups with alkyl or aryl groups in water, such as carboxylates, sulfates and sulfonates. This type of emulsifier is the most commonly used and the largest in production, and common commodities are: soap, sodium stearate, sodium lauryl sulfate and calcium dodecyl benzene sulfonate (structural formula such as). Negative ionic emulsifiers are required to be used under alkaline or neutral conditions, not under acidic conditions. When formulating emulsions using a variety of emulsifiers, negative ionic emulsifiers can be mixed with each other or with nonionic emulsifiers. Negative and positive ion emulsifiers cannot be used in one emulsion at the same time, if mixed will destroy the stability of the emulsion.

2. Positive ionic emulsifier

Ionization in water to generate positive ionic hydrophilic groups with alkyl or aryl groups. There are fewer varieties of such emulsifiers, all of which are derivatives of amines, such as N-dodecyldimethylamine, which can be used for polymerization reactions.

3. Non-ionic emulsifier

It is a new class of emulsifiers, which are characterized by non-ionization in water. Its hydrophilic part is a variety of polar groups, common are polyoxyethylene ethers and polyoxypropylene ethers. Its lipophilic fraction (alkyl or aryl) binds directly to oxyvinyl ether bonds. Typical products are p-octylphenol ethoxylates (structural formulas such as). The oxygen atoms on the polyether chain of nonionic emulsifiers can be associated with water to form hydrogen bonds and can therefore be dissolved in water. It can be used under both acidic and alkaline conditions, and the emulsification effect is very good, and it is widely used in the production of chemical, textile, pesticide, petroleum and latex.

Second, the role of emulsifiers

Emulsifiers are surfactants that stabilize emulsions. Therefore, after adding an emulsifier to the oil-water system, the water and oil can be mixed with each other to form a completely dispersed emulsion.

Emulsifiers not only improve the stability of the emulsion, but also determine the type of emulsion.

The types of emulsions have expanded from the traditional oil-in-water and water-in-oil types to multiple emulsions, non-aqueous emulsions, liquid crystal emulsions, chromogenic emulsions, gel emulsions, phospholipid emulsions and liposomal emulsions.

Third, the use of emulsifier

Various emulsifiers interact with starch and protein in flour to form complex complexes, which enhance gluten, improve processing performance, improve bread tissue, extend freshness and other effects, and the addition amount is generally 0.2%~0.5%

After the food emulsifier is added to the food, it can significantly reduce the interfacial tension between oil and water, so that the oil (hydrophobic substances) and water (hydrophilic substances) that are not compatible with the food emulsifier form a food additive that stabilizes the emulsion.

Precautions for use:

1. Emulsifiers with different HLB values can prepare different types of emulsions, and choosing the right emulsifier is the basic guarantee for achieving the best results.

2. Due to the synergistic effect of composite emulsifiers, compound emulsifiers are usually used, but when selecting emulsifier pairs, it is necessary to consider that the difference between the high value and the low value of HLB should not be greater than 5, otherwise the best stable effect will not be obtained.

3. The emulsifier consumed by the user is the national strict standard dosage, which will not be harmful, but it is not excluded that there are illegal businesses that use emulsifiers excessively, and if excessive use of emulsifiers, it will affect human health.

4. Before the emulsifier is added to the food system, it should be fully dispersed or dissolved in water or oil to make a slurry or emulsion.