IN-VITRO CHLOROPHYLL DEGRADATION IN STORED BROCCOLI (BRASSICA-OLERACEA L. VAR. ITALICA PLEN.) FLORETS

In vitro chlorophyll (Chl) degradation in broccoli (Brassica oleracea L. var. italica Plen.) florets was studied by HPLC analysis of the deg radative products. With the degradation of Chl, chlorophyllide a (Chli de a) and phaeophorbide a (Phb a) increased gradually in the reaction mixture containing the broccoli extract. This was followed by the form ation of pyrophaeophorbide a (Pyro-Phb a) after 2 h of reaction time. 13(2)-hydroxychlorophyll a (Chl a-1) showed minimal change during the reaction. Chl a degradation and Chlide a formation decreased significa ntly in an extract of yellow broccoli florets during 4 days storage at 15 degrees C. Pyro-Phb a formation also decreased gradually, but Chl a-1 formation did not decrease during storage. Thus, in an in vitro sy stem of extracted broccoli florets, Chl a was degraded initially to Ch lide a or Chl a-1. Chlide a subsequently was degraded to Pyro-Phb a th rough Phb a. Chl a-1 and Pyro-Phb a could be finally degraded to colou rless low molecular weight compounds. (C) 1997 Elsevier Science B.V.