Malondialdehyde (MDA) measurement was carried out by the
method of Heath and Packer (1968), with a slight modification.
Fresh peel tissue (2.0 g) from ten fingers was homogenized in
10 mL of 10% trichloroacetic acid, and centrifuged at 10,000 × g
for 20 min. The supernatant was collected, and 1 mL of it was
mixed with 3 mL of 0.5% thiobarbituric acid. The mixture was
boiled for 15 min, then quickly cooled in an ice bath and centrifuged
at 12,000 × g for 15 min. The supernatant was collected
and used to measure absorbance at 450, 532, and 600 nm. The
MDA concentration was calculated according to the formula:
6.453 × (A532 − A600) − 0.563 × A450. The concentration of MDA
on a fresh weight basis was calculated mmol kg−1.