John,
The initial analysis which you quoted was apparently for the compound dopamine which is produced by enzymatic conversion from levodopa.
Levodopa can cross the blood-brain barrier following ingestion whereas dopamine can not, therefore the conversion must occur inside the brain cells.
I do not know whether bananas or your fermentation product have significant amounts of levodopa in them or not, but would not expect either one to have efficacy unless it were present.
Robert