expressed as μL h–1kg–1 FW.
Firmness was measured using a universal traction–
compression machine (Instron 5542, Instron Corp., USA)
with computerized data acquisition equipped with a 4-mm
diameter flat plunge.force curves were recorded using
the computer program of the force gauge and the maximum
force Newton (N) was calculated.
Starch was extracted from dried tissues of banana and
plantain using 80% ethanol according to the methods of
Smith (1988). The extracting solution was incubate with
iodine reagent(shafiaa et al. 2005), and the absorbance
was measured at 620 nm against a blank (0.2 mL of water
in 5 mL of iodine reagent). The starch contents were represented
as mg g–1 DW.
Soluble sugars were extracted from dried tissues of
banana and plantain. 50 mg (DW) of sample were homogenized
with 4 mL
of
80%
ethanol solution in a mortar
and
pestle. After
heating the
homogenate in
a water bath
at
80°C
for
40 min,
the
insoluble residue was removed
by
centrifuging at
4
000
r min
for 8 min. The precipitate
was re-extracted with 80% ethanol. The supernatant was
collected to determine the soluble sugar using anthranone
colorimetry with glucose as a standard (Hao et al. 2006).