Lots of folks like to disparage stabilizers, but they’re one of the most important classes of food additives. As their name implies, their main job is to prevent things from happening. If a catalysts are instigators of reactions, stabilizers can be thought of as their opposite. Sort of like chemical cops, they keep molecules of different kinds from behaving badly, reacting with one another or separating out from one another. Thus their primary function is textural, keeping foods uniform and even.
Gelatin, a protein, is a stabilizer. So are the carbohydrates xanthan gum, guar gum and carrageenan. What all these molecules have in common is that they are long and languid. Dispersed in a liquid, they’re good at getting in between other molecules, keeping them from reacting or forming big agglomerations.
Of course once you introduce a whole bunch of long, stringy molecules into a liquid something else starts to happen: the liquid’s ability to flow is hampered. Which is why stabilizers frequently do double-duty as thickeners.