So the good news for you is you realistically don’t even need water soluble cannabinoids because you couldn’t really have an easier application. Protein shakes have it made because you’re picking the one beverage that the consumer is mixing for you. You don’t actually need a “stable” emulsion but even if you did, milk proteins are going to do the “heavy lifting” here (yes, that pun was bad). We really should all be taking notes from the supplement industry because they have been doing this with far more substantial amounts of powders for decades. A little bit of cannabinoids in 8-12 ounces of fluid is a walk in the park.
The only thing to know is you can’t dump a couple grams of isolate powder into a tub of whey isolate and call it a day. You’ll want to be sure that powder itself is mixed professionally to have a decent shelf life. If you’re having a protein powder company mix in your CBD for you, they already have the equipment and anti-clumping agents to ensure that it will have a good shelf life and stay evenly mixed. If you’re trying to penny pinch and mix your cannabinoids into the powder yourself, PM me and I may be able to point you in the right direction.
I’d only worry about emulsions/water soluble cannabinoids if you were creating RTD protein drinks to sell in gyms or health food stores. Pre-bottled supplement drinks are actually a massive chunk of the market nowadays so that might be something to consider if you have the $ for R&D. Cannabinoids aren’t going to be the hard part. Shelf life stability in powder form is one thing but shelf life in a liquid is a totally different beast when 20-30 grams of protein gets involved.