determined by measuring the increase in absorbance at
460 nm, using o-dianisidine as chromogenic indicator
(Fbster & Pr&amo, 1989) in a Perkin-Elmer Lambda
15 UV-vis double beam spectrophotometer, equipped
with a recorder. Ten grams minced pineapple fruit was
homogenized with 20 ml 0.05~ sodium potassium
phosphate buffer pH 6.0, in a Sorvall Omnimixer at
2°C. The enzyme extract was filtered through glass
wool and centrifuged at 6000 rpm and 4°C for 20 min.
An aliquot, appropriately diluted, was used for the enzymatic
assay. The reaction mixture contained: 2.8 ml
0.05 M sodium acetate buffer pH 5.5, 0.2 ml 0.5%
hydrogen peroxide (w/v), 0.1 ml 0.25% o-dianisidine (w/v)
and 0.05 ml enzymatic extract. Each value represents a
mean of a duplicate determination of three different
samples. POD activity was expressed as A absorbance/
min/mg protein.