The total phenolic content (TPC) of the extracts wa
s determined colorimetrically using
Folin–Ciocalteu’s reagent as described by Kriengsak
et al.
(2006) with some minor
modifications. Fruit extracts (20 HL) were mixed wi
th 100 HL of Folin?Ciocalteu’s reagent,
left for 3 minutes and subsequently 300 HL of sodiu
m carbonate (0.7 M) was added and
vortexed. The absorbance of the resulting mixture w
as measured at 725 nm using a UV
visible spectrophotometer (UV 1601, Shimadzu, Japan
) after leaving for 30 minutes at the
room temperature (25 °C). The results were expresse
d as mg gallic acid equivalents (GAE)
per litre of extract using a gallic acid (50 – 500
mg/L) standard curve.