Abstract:
The objective of this study was to investigate taro
[C
olocasia esculenta
(L.) Schott]
corm quality as determined by changes in starch mor
phology and degradation during
storage after harvest. Starch is the major nutrient
component of taro corms and its
quality in corms that are stored as planting materi
al or consumption has not been fully
explained. Scanning electron microscopy was used to
examine the changes that occur to
the surface morphology of starch granules in corms
of taro landraces,
Dumbe-dumbe
,
Mgingqeni
and
Pitshi,
stored at cool (12ºC) and ambient (20ºC) temperatu
res. Alpha-
amylase activity and sprouting were used as indicat
ors of changes in the starch
granules, and hence corm quality, during storage in
polyethylene bags, card boxes, and
mesh bags. The degradation of starch granules, alph
a amylase activity, and sprouting
increased over storage time and varied with landrac
es, storage material, and
temperature. Overall, there was 23% more alpha-amyl
ase activity and 67% more
sprouting at 20ºC compared with 12ºC. With respect t
o storage material, polyethylene
bags showed the highest alpha-amylase activity (0.1
8 EU 0.1 g
-1
) followed by card boxes
(0.15 EU mg
-1
0.1 g
-1
) and mesh bags (0.14 EU mg
-1
0.1 g
-1
). A similar, but more
pronounced, trend was observed for sprouting. The f
indings have implications for
selection of storage material for food and propagul
e storage.
Keywords
:
Colocasia esculenta,
Electron microscopy, Landrace, Starch granules
