Dress up your Dressings
To obtain stabilization in mayonnaises and dressings, an emulsifier needs to be used to rapidly decrease the interfacial tension during the homogenization step.
16/06/05 Emulsified sauces like mayonnaises and dressings accompany almost every savory meal. Traditional sauces that make up the most of our good home cooking however have always been a challenge for the food industry. The target is to create products that may tolerate long-term storage without losing their appearance and taste. Apart from choosing the right emulsification technology, the selection of emulsifiers and stabilizers is the most important aspect in such formulations.
Emulsions like dressings and mayonnaises result from mixing the two mutually insoluble liquids - oil and water. They are disperse systems consisting of an internal oil phase and an external, continuous water phase. The result is an oil-in-water emulsion. To obtain stabilization, an emulsifier needs to be used to rapidly decrease the interfacial tension during the homogenization step. This allows the disruption of the oil droplets and the creation of very small ones. The use of hydrocolloids also helps to stabilize the emulsion. By increasing the viscosity of the external phase they slow down the motion of the oil droplets, thus reducing the risk of creaming or coalescence. Additionally the right choice of hydrocolloids provides the respectively desired texture and organoleptic properties for each product.
- Egg yolk has been the traditional emulsifier for many years as it provides excellent emulsifying properties in the salty acid medium of dressings and mayonnaises along with a full body and unique taste. Egg yolk provides a safe emulsification process from the technological point of view and is suitable for emulsified sauces containing up to 80% oil.
Nowadays, health and religious claims have raised the need for alternative emulsifiers in dressings and mayonnaises, replacing the traditionally used egg yolk. „Cholesterol free“, „GMO free“, „allergen free“ and even „dioxin free“ are slogans that appeal to consumers being aware of nutritional, religious and ethnic issues.
- Emulsifying pectin or starch, propylene glycol alginate (PGA), milk protein or lecithin meet the demands of the market for vegetarian solutions. Together with hydrocolloids, they ensure superior emulsion stability for a variety of emulsified sauces and dressings during processing, storage and final consumption. In addition to the vegetarian aspect, these emulsifiers can provide special technological benefits to the formulation, like freeze-thaw-stability and heat stability, thus adding more value from a convenience point of view.
- PGA has been a well known and popular emulsifier and stabilizer especially in North America for many years. PGA brings together emulsifying and thickening properties in combination with a full body and a good mouth feel even in products with a low fat content. Recently new products have appeared on the market and studies have shown that even products only known so far as thickeners - like starch or pectin - can also exhibit emulsifying properties in sauces.
- Lecithin is a widespread emulsifier in food applications ; lecithin is predominantly obtained from vegetable oilseeds such as soybeans. Lecithin in the commercial sense covers a variety of phospholipids that provide, due to their amphiphilic molecular structure, a high surface active functionality. By using lecithin to reduce the interfacial tension between oil and water, it is possible to achieve fine dispersions. Moreover, the concentration of lecithin at the interface between the phases protects the droplets from coalescing again. Lecithin can act as water-in-oil- and as oil-in-water-emulsifier depending on the type of lecithin used. The most suitable lecithin for oil-in-water-emulsions like dressings and mayonnaises is Emultop, a hydrolized de-oiled lecithin.
During the enzymatic hydrolysis of lecithin one fatty acid is removed, thus reducing the hydrophobic parts of the molecule and making the entire phospholipid molecule more hydrophilic. With the following de-oiling step the hydrophilicity of the lecithin is further increased.
In general, the emulsion type formed depends on the emulsifier and its preference for the individual phase in which the emulsifier is dissolved or dispersed. Hydrophilic emulsifiers like Emultop that are dispersible in water preferably form the o/w type of emulsion. Emultop tolerates acid and salty media and can be used as innovative emulsifier in low and medium viscous emulsified sauces even when pasteurization of the product is an issue.
- Dairy protein is a rather traditional emulsifier in dressings and mayonnaises. However, there are new developments in this field, for example resulting in an increased stability when emulsions are frozen and subsequently defrosted. Benefits like freeze-thaw-stability are terms linked to convenience that has been a trend in the market for the past few years. To meet the consumer’s desire for convenience, manufacturers of dressings and mayonnaises may see a bonus in offering their products together with deep-frozen products like potato chips and wedges or prawns. Wouldn’t it be convenient for consumers to have not only the chosen food but also the corresponding seasoning all in one packaging?
The manufacture of deep frozen mayonnaises or dressings however poses a great challenge towards the emulsifiers and stabilizers to be used in such products. Apart from stabilizing the emulsion in an acid and salty medium, they need to ensure stable interfaces that withstand growing ice crystals during the freezing period especially when temperature variations occur. Such ice crystals may lead to leakages in the interfaces, possibly causing coalescence of the emulsion droplets which might finally result in oil separation and as a consequence unstable products.
Degussa Food Ingredients’ Business Line Texturant Systems has developed complete solutions for freeze-thaw-stable emulsified sauces with oil contents up to 50%. This development covered the selection of the best suitable dairy proteins and the well-balanced combination of hydrocolloids. The resulting products within the Lygomme KCT series consist of both emulsifiers and texturizers that provide emulsions with a smooth, creamy and short texture. These special combinations at the required levels guarantee excellent emulsion stability during processing as well as freezing and thawing even when the products are thawed in the microwave. Storage tests show that the emulsified sauces remain stable for freezing periods of at least 1 year.
The quantity of oil in an emulsion and the emulsion quality contributes a lot to its final texture. But the lower the oil content, the more influence comes from the water phase and its texturizing ingredients. Therefore a careful selection of hydrocolloids is necessary to ensure not only the required viscosity but also the desired structure. A good cling to salad ingredients may be wanted as well as an easy dosing out of the packaging or full body in low fat products. On the other hand there are technological requirements to be considered as well. Depending on process or storage conditions the stabilizers need to be shear stable, heat or freeze-thaw stable and they need to tolerate acid and salty media without any changes in viscosity and texture. The most widespread hydrocolloid in emulsified sauces is xanthan gum. With its emulsion stabilizing properties and its high acid and salt tolerance it is a unique stabilizer for dressings and mayonnaises. However when being used together with other hydrocolloids like guar gum or locust bean gum synergies can be used that do not only provide additional viscosity but also a better mouth feel and body.
Degussa Food Ingredients’ Business Line Texturant Systems uses such synergies between single hydrocolloids and offers, with the hydrocolloid blends from its LygommeKCT series, tailor-made solutions for every application. Additionally, the blends for freeze-thaw-stable mayonnaises from the Lygomme KCT series are easy to handle, can be used in vegetarian formulations, are GMO free as well as free of starch and cholesterol.
Emulsified sauces are complex systems with a large variety of technological, health and ethnic requirements. Recent developments in the food ingredients sector help the manufacturers of dressings and mayonnaises to satisfy the wishes of their customers. With its lecithin range, especially Emultop and the blends of the Lygomme KCT series Degussa Food Ingredients’ Business Line Texturant Systems presents emulsifier and stabilizer concepts for all kinds of savory emulsified sauces.
