Carboxyl groups have an electronegative oxygen atom double bonded to a carbon atom. This carbon-oxygen bond is very polar and the fact that its a double bond increases the polarity of the bond.
PEA agar, also referred to as Phenylethyl Alcohol Agar is a medium  used by microbiologists to grow microorganisms. The ingredient that  supplies nitrogen is casein. Making the world better, one answer at a time.
Not to be confused with 1-phenylethylamine. Phenethylamine (PEA), also known as Î²-phenylethylamine (Î²-PEA) and 2-phenylethan-1-amine, is an organic compound and a natural monoamine alkaloid, a trace amine, and also the name of a class of chemicals with many members that are well known for their psychoactive and stimulant effects.