A coating of sugar and glycerol should work and it’s cheap...............
Sugar no it would encourage microbe growth. Glycerol yes but it’s a sticky liquid and would trap sediments like nobodies business.
You do know that mono and diglycerides are the base molecule for glycerol right? Glycerol is a sugar alcohol acid of the base molecule glycerin which is the bulk hydrocarbon chain of both mono and diglyceride, and triglycerides too. You get glycerin by using a base like NaOH to break the head off a glyceride molecule forming Na based soap and glycerine in the process.
If you use NaOH an alcohol such as methanol and di/triglycerides you get a fatty acid ester(biodiesel) and yup pure glycerin. It’s the back bone of all of the fatty acids.
Apeel skips the sugar alcohol and goes right to glyceride based polymer chains it’s organic polymers no different than cellulose, hemicellulose all are repeating chains of a base hydrocarbon unit. Cellulose is repeating glucose units, hemi is pentose, you can polymer mono or diglycerine based too. Grapes in their skins already did the polymer work for you their skin is mono and diglycerides linked together it is what the skin of a grape is an organic polymer network.
They just extracted that and and it into a powered that when hydrated dries back to effectively air right grape skins it’s actually genius.