Characterization of chlorophyll pigments in ripening canola seed (Brassica napus)

This study characterizes the chlorophyll pigments in ripeningBrassica napus seed. Seed samples, collected weekly as the crop ripened, were analyzed by high-performance liquid chromatography to characterize chlorophyll pigment composition. Chlorophyll A, chlorophyll B, pheophytin A and pheophytin B were the predominant pigments, while pheophorbide A, methylpheophorbide A and pyropheophytin A were minor components. No differences in pigment composition were observed between the three cultivars tested or between early and late seeding dates. There were differences in pigment composition between the two years of the study, which may result either from seed aging during storage or from environmental influences. Pigment composition was dependent on seed maturity, with physiologically mature green seeds containing both chlorophylls and pheophytins, but fully mature seeds containing only chlorophylls. Pheophytins and the minor components appeared transiently, presumably formed from the chlorophylls and subsequently degraded. The ratio of chlorophyll A/B increased during seed ripening, with fully mature canola seed having a chlorophyll A/B ratio twice that of physiologically mature green seed. The “B” derivatives degraded faster than the “A” derivatives, suggesting enzymatic reactions. The initial steps in the chlorophyll breakdown pathway in canola seed appear to be:

[1]  A. Johnson-Flanagan,et al.  Degreening in canola (Brassica napus, cv. Westar) embryos under optimum conditions , 1990 .

[2]  A. Kiritsakis,et al.  Studies in photooxidation of olive oil , 1985 .

[3]  A. Johnson-Flanagan,et al.  The role of chlorophyllase in degreening canola (Brassica napus) seeds and its activation by sublethal freezing , 1990 .

[4]  J. Man,et al.  Hydrogenation of canola oil as affected by chlorophyll , 1986 .

[5]  L. Appelqvist,et al.  The Effect of Seed Pretreatment and Extraction Conditions on the Amount of Minor Components in Seed Oils II. Chlorophyll and Related Pigments , 1984 .

[6]  J. Daun,et al.  Characterization of chlorophyll pigments present in canola seed, meal and oil , 1992 .

[7]  D. Erikson.  Edible fats and oils processing : basic principles and modern practices : world conference proceedings , 1990 .

[8]  J. Jen,et al.  ON THE PHOTODECOMPOSITION OF CHLOROPHYLL IN VITRO‐II. INTERMEDIATES AND BREAKDOWN PRODUCTS * , 1970, Photochemistry and photobiology.

[9]  Y. Endo,et al.  Prooxident activities of chlorophylls and their decomposition products on the photooxidation of methyl linoleate , 1984 .

[10]  F. R. Harper,et al.  REVISED GROWTH-STAGE KEY FOR BRASSICA CAMPESTRIS AND B. NAPUS , 1975 .

[11]  J. Daun,et al.  The effect of freezing on the analysis of chlorophyll content of canola seed (Brassica napus L.) , 1992 .

[12]  J. Daun,et al.  Determination of chlorophyll pigments in crude and degummed canola oils by HPLC and spectrophotometry , 1989 .

[13]  J. Daun,et al.  A comparison of high-performance liquid chromatography and spectrophotometry to measure chlorophyll in canola seed and oil , 1994 .

[14]  A. Johnson-Flanagan,et al.  PEROXIDASE-MEDIATED CHLOROPHYLL BLEACHING IN DEGREENING CANOLA (BRASSICA NAPUS) SEEDS AND ITS INHIBITION BY SUBLETHAL FREEZING , 1990 .