Emulsifiers are primarily used to produce and maintain emulsions. These additives also have other functionalities in food matrices, such as aeration, increasing shelf life, mouthfeel, texturing and fat replacement. The latter especially is interesting from a possible health perspective, the more so when the emulsifiers do not have to carry an E-number.
Because of their versatility, food emulsifiers can be found in a huge variety of food applications: mayonnaises, bakery products, ice creams, fat spreads, salad dressings etc. (see page 22 for a comprehensive overview).
Broad functionalities
Because of emulsifiers main functionality, mayonaises or salad dressings - just to name a couple of examples - do not break down in a water and oil phase over its shelf life.
As mentioned before, emulsifying is not the only functionality. For example, stearoyl lactylates and mono- and di-glycerides can retard staling in baked goods by interfering with starch retrogradation. In chocolate, emulsifiers are used to reduce viscosity, which allows for a reduction in the amount of cocoa butter, and subsequently lowers costs as well as a few calories. Emulsifiers in cake batter facilitate the release of cake from pans.
Growth expected in Asia Pacific region
Negative side-effects
A possible downside, ironically, for emulsifiers could be reports about some negative side effects of these additives.
In a study at Georgia State University in the US, published in Cancer Research, mice were administered polysorbate 80 (E433) and carboxymethyl cellulose (E466) via their food. They were given dosages corresponding to high levels of consumption of the processed foods that contain these emulsifiers.
The diet led to a change in the gut flora in the mice, causing mild inflammation that made the mice more susceptible to the development of intestinal tumours.
Criticism of this study, pinpoints the disproportionate amounts of emulsifiers the mice were fed. Similar criticism arose about studies on aspartame. What is also missing is further research. The study needs to be reproduced by other teams and possible side effects should be eventually confirmed by human clinical trials with control groups that hardly consume emulsifiers. Furthermore, the relation between inflammation of the gut flora and intestinal cancer needs to be investigated. For the time being, there is no causal effect demonstrated.
Nanoemulsions
Because of market saturation in some regions, the future of emulsifiers may lie in other functionalities, for example encapsulating, stabilizing and delivering functional compounds. Nanoemulsion technology is particularly suited for the encapsulation and delivery of these compounds, leading to products which have more potential advantages than conventional emulsions. Nanoemulsions are ultrafine dispersions of at least two immiscible liquids (oil and water) possessing globules of submicron size range (10 nm - 100 nm). Nanoemulsions garner increasing interest in a number of sectors, including the food industry. These emulsions could be used for lipophilic constituents like flavours, omega-3 fatty acids, vitamins, preservatives or nutraceuticals. They have a number of potential advantages over conventional emulsions like incorporation into optically transparent products, may enhance the texture, stability, and bioavailability of certain food products. The formation of nanoemulsions requires processes like high energy emulsification with the help of high pressure homogenizers, sonication, and some low energy emulsification.
Natural emulsifiers
Another area which could foster innovation is the nature of emulsifiers. Most emulsifiers are synthesized and have to carry an E-number. The latter is an indication that the additive in question is safe for human consumption. The current trend - clean labelling - in the food industry, however, is to eliminate these E-numbers as much as possible, due partly to recent negative reporting on some E-numbers, mainly a combination of various food colourants.
This has sparked R&D activity into natural resources that are able to offer the same functionalities as synthesized emulsifiers. There are various sources available, such as biosurfactants, phospholipids, biopolymers (proteins, polysaccharides) and colloidal particles (starch).
