a logical way to remember is that:I don't know about you
but I often forget what is secreted from these
So here's how I remember it
The chef brings you meat with a side serve of vinegar
Which means that Chief cells produce pepsinogen to digest proteins while parietal (side) produce the acid
the CHIEF function of the stomach is to digest protein,so the CHIEF cells will secrete the CHIEF(read most important) factor that digests..i.e---pepsin
the other one is the other on!