you could eat raw rue seeds(3-5g), and then try and down 3g or so of mimosa (probably more, i would imagine it would be much less potent consumed in this manner).  the body load would be incredible and you would probably purge almost instantly (just from the tannins alone).  wouldn't be ayahuasca in the technical sense, but i doubt you could eat the necessary dose of aya (which again, would probably be higher than usual just due to method of ingesting).  perhaps you could do a CWE of sorts, just juice the plant material without cooking it.

as far as tobacco, i am far from an expert (or even willing to ingest it), but what would lead you to believe lemon juice would potentiate it?

just the acid lysing the cells?