Plastid Ultrastructure, Chlorophyll Contents and Colour Expression during Ripening of Cavendish Banana at 18
P. Ding, S.H. Ahmad, A.R.A. Razak, N. Saari and M.T.M. Mohamed
Program and Abstract. Australasian Postharvest Horticulture Conference. Royal Lakeside Novote., Rotorua, New Zealand. 27-30 September 2005. July 5-10, 2005. Page 21
2005
บทคัดย่อ
Plastid Ultrastructure, Chlorophyll Contents and Colour Expression during Ripening of Cavendish Banana at 18
When Cavendish bananais ripened at tropical ambient temperature (27°C) the peel fails to degreen although the pulp has softened. However, the peel will degreen to a yellow colour when the fruit is ripened at 18°C. The inability of the peel to degreen could be due to the retention of plastids and chlorophyll during the ripening process. A study was carried out to investigate the relationships among the plastids ultrastructures, chlorophyll contents and peel colour of Cavendish banana ripened at 18±2 (C18) and 27±2°C (C27). The peel of Cavendish banana undergo complete degreening when the fruit was ripened at temperature of 18±2°C to produce a yellow fruit at ripening stage (RS) 6 after 9 d of ripening. In contrast, C27 failed to degreen even though the pulp had softened. By day 5 after ripening with acetylene, brown specks started to appear on the fruit peel indicating that senescence had commenced. Transmission electron microscopy revealed that the grana-thylaloid membrane of C27 at day 5 was retained with retention of57% total cholrophyll content in the fruit peel. Total chlorophyll content of C27 correlated significantly with L*,C* and h° colour values. The higher percentage of total chlorophyll retained in C27 compared to C18 did not allow the existing peel carotenoids to express the yellow peel colour completely, thus producing a pale-green fruit.