Oompa Loompa, do-ba-dee-doo, I’ve got a perfect puzzle for you. Oompa Loompa, do-ba-dee-dee…
In Roald Dahl’s book Charlie And The Chocolate Factory, Willy Wonka proudly displays a stick of Three Course Dinner Chewing Gum (watch the video here), which he claims can reproduce the flavours of every individual course of a full meal. The gum is able to convey the flavours of ‘tomato soup, roast beef and baked potato, and blueberry pie and ice cream’. Wonka’s fantasy concoction has been nothing but a dream for millions of kids across the world. But science and technology is changing the future of food, and these nanoparticles may hold the answer to creating a three course gourmet gum. But, unfortunately for prolific gum-chewer Violet Beauregarde, the gum is not quite ready and has the unfortunate side-effect in that it turns the user into a giant blueberry before they reach dessert.
Figure 1. The process of creating a colloidosome involves adding aqueous solution to oil containing colloidal particles. The particles adsorb onto the surface of the droplet and attract by Van der Waals forces, forming a shell.
Fortunately, scientists have not turned any children into giant fruits – yet. But they have been investigating the potential use of colloidosomes in creating a single, edible substance that can encapsulate several diverse flavors in a precisely controlled manner. These novel oil-on-oil particles exist in an aqueous emulsion as encapsulators for food. Colloidosomes originated from the Pickering emulsion, an immiscible mixture stabilized by solid particles which have a tendency to adhere onto interfaces between solid and liquid. The effect was revolutionized based on the idea of preventing droplets from coalescing, made possible by the addition of solute particles to the solution, which thus would stabilize the emulsion. Such an emulsion has many properties such as hydrophobicity, size, and shape.
This versatile phenomenon has since then been furthered by collaborative efforts from engineers, resulting in what we now call colloidosomes, where latex particles are used as the stabilizing solute and are fused together to synthesize a permeable shell. An important factor in ensuring that the adsorbed particles surrounding the solute are locked together to form the permeable shell is Van der Waals forces. These Van der Waals forces interactions, sometimes forcefully induced through destroying the coating surrounding the particles, hold the shell together. The use of electrostatic layer-by-layer deposition allows for small oil droplets to be placed around a larger oil droplet and distributed in an aqueous phase. This technique can minimize the emulsion’s vulnerability to splitting apart due to gravitational forces as well as facilitate new applications, such as the design of controlled release mechanisms. These structures are unique in that their properties, being primarily size, permeability, mechanical strength, and compatibility are easily controllable and thus provide for an effective means of usage. The multifaceted nature of these capsules allows for increased choice of materials, being that the diverse properties could be controlled depending on the fragility and sensitivity of what is inside.
Figure 2. A dimensional image of the shell of an actual colloidosome.
Exploring the possibilities of what can effectively be delivered inside these colloidosomes, whether it be drugs, proteins, etc. is an exciting subject in the field of biomedical applications. But researchers are beginning to explore not only the therapeutic potential of these capsules but also their potential to envelop several layers of flavors, thus giving the effect of tasting different kinds of food at different times while chewing. The primary principle behind this proposed controlled release of flavors is that the different flavors are contained in colloidosomes possessing different levels of strength and permeability. So while the relatively weaker colloidosomes would break and release their contents more easily in only a minimal amount of chewing time, and perhaps even just on contact with saliva, the colloidosomes with more sturdy and secure structures would break after more chewing. The resulting sensation is then that different flavors are being released as a person continues to chew.
So it seems that Wonka’s fantasy three course gum is no longer just a fantasy but is quickly becoming an exciting reality. In fact, in 2010, London housed a chewing gum factory in a Whiteleys shopping center in which anyone could create their own uniquely flavored gum from 40,000 different combinations of flavors. While there are still some kinks to work out, such as ensuring that the first flavor of the gum is entirely gone by the time the second flavor explodes in your mouth, these tiny, edible capsules called colloidosomes are bringing to life an iconic movie moment that had inspired scientists across the globe.
BCA Chemistry 