Cell wall hydrolases and amylase in kiwifruit softening
Claudio Bonghi, Silvana Pagni, Rajko Vidrih, Angelo Ramina and Pietro Tonutti
Postharvest Biology and Technology. Volume 9, Issue 1, October 1996, Pages 19-29.
1996
บทคัดย่อ
The activities of amylase, 
-galactosidase
(-GAL),
polygalacturonase (PG), and endo-1,4--glucanase
(EG), and ethylene evolution, were measured during ripening in kiwifruit (Actinidia
deliciosa (A.Chev.) (C.F. Liang et A.R. Ferguson var deliciosa, cv.
Hayward). Fruit, harvested at firmness values (FV) of 65 N and a soluble solid
(SS) content of 9%, were maintained in air at 20°C for 40 days, until they
reached the edible stage. Fruit firmness decreased throughout the experimental
period and the lowest FV (about 5 N) was reached after 38 days of storage. SS
content increased rapidly to about 13% within 15 days, then the rate of
accumulation slowed and the SS content of 14.1% was reached after 33 days.
Ethylene climacteric was a late event occurring at a FV of 10 N. The highest
amylase activity was measured at harvest. During storage it declined, although
a slight rise was detected at 33 days. -GAL
activity was very low at the beginning of storage and increased throughout the
experimental period, while PG activity was detected only after the fruit FV was
below 10 N. EG activity decreased within the first three days of storage, then
increased and peaked 15 days after harvest. Later, EG activity remained low but
increased again at the end of the storage period. Application of propylene (500
ppm) to fruit that had softened to 30 N in air stimulated fruit softening and
EG activity, and induced the accumulation of an EG-related peptide: the other
enzymes appeared not to be affected by the gas.