I have come upon something that has me stumped...
In vegetable cookery at culinary school, it was a given that acids dull the green color (chlorophyll) in vegetables therefore it must be added towards the end (ie, green beans tossed in tomato sauce right before plating). With red vegetables, acid improved the color and with whites it helps set the white color.
Now I have come upon several observations, in particular a recipe by Michael Chiarello for pesto, which specifically call for Vitamin C/citric acid/ascorbic acid to set the green color in the pesto. He blanches the basil leaves 15 seconds and then shocks in ice water, then dries it, then purees it w olive oil, the usual pesto ingredients and the acid. As stated, the acid is there to keep the pesto looking green for a longer time.
Ok, so what gives? The chlorophyll in the vegetables is the same as the chlorophyll in the herb (basil), so what changes? Am I overlooking something - am i missing something here? Ironchef, Michael in Ftw, Andy M, Nicholas.... anyone?!