Total phenolic contents determination
The TPC of each Thai red curry paste
sample was determined using the Folin-Ciocalteu
method, described by Choi et al. (2006), with some
modifications.
Paste extracts of 0.5 mL were added to
test tubes followed by 9.5 mL of distilled water,
0.5 mL of Folin-Ciocalteu reagent and 2 mL of
10% sodium carbonate solution. The contents of
the test tubes were mixed thoroughly. After
standing for 1 h at room temperature, the
absorbance was measured at 730 nm with a UVvisible
spectrophotometer (SHIMADZU 1700,
Japan). The results were expressed as milligram
gallic acid equivalent/gram dry matter.
cooled rapidly to room temperature and stored at
-60°C until analysis.