the idea is to add a thickening agent to a fruity liquid to emulsify it well with oil. Basically an emulsified smoothie. The goal is a fruity fatty thick dip or salsa with the texture of mayonnaise. Since you can't emulsify just water/fruit juice with oil, I thought to make the liquid thicker to emulsify it then. This is because I often read "is used as thickening agent and emulsifier". Thus, I wonder whether there are thickening agents that work especially well for emulsification? Options are arrowroot, guar gum, tapioca and other starches. With which thickening agent would it work best? Can someone confirm that it would work this way, or has some experience with a thickening agent for emulsification? Any other ideas how to achieve this are appreciated as well! Edit: with an emulsifier like lecithin it's no problem for sure, but the goal is to emulsify with a thickening agent. 
I have experimented a bit and came to the conclusion that  thickening agents do indeed work as emulsifiers, although not 100% perfect like real emulsifiers. Yet in scientific papers they are listed under emulsifiers. What happens is, that only approx. 2% of the oil separates again after emulsion  albeit they do work, the texture doesn't become as stiff as with emulsifiers. The problem is that the thickening agent made it already thick and creamy, adding oil makes it first a bit more liquid because there's simply more liquid in total. Adding more oil compensates a bit, but then it stays there. (The oil keeps emulsified to 98%)   In short, thickening agents do work as emulsifiers but are useless for emulsion, mainly because the liquid is already thick anyway and secondly the textures just doesn't become as delicious as it does in mayonnaise. I had the feeling that starch did work a bit better than fibers like guar gum. 