Total flavonoid contents of pineapples were determined by using the aluminium chloride colorimetric method as described by Willet (2002), with some modifications. Methanol extracts (0.5 mL), 10% aluminium chloride (0.1 mL), 1 M potassium acetate (0.1 mL) and distilled water (4.3 mL) were mixed after incubation at room temperature for 30 min. The absorbance was measured at 415 nm
using a HITACHI, U-2000 spectrophotometer. Quercetin was used to make the calibration curve. The estimation of total flavonoids in the extracts was carried out in triplicate and the results were averaged.