I cant recall seeing anything about eating or not eating with them, unless something is cited Im going to go on thinking it doesnt matter.
IMO the best procedure for BCAA's is, mix 4-5 scoops in a bottle, drink about 1/4 on the way to gym, sip 1/4 at gym (also drinking water at gym), upon getting home, at 50g WMS to the bottle, fill with water and drink it down.