Determination of Total Phenolics Content (TPC) of Oil
Samples by the Colorimetric Method
The total phenolics content (TPC) was determined using
the Folin–Ciocalteu reagent. Different aliquots were mixed
with 0.2 ml of Folin–Ciocalteu reagent and were kept for
3 min. About 1 ml of 15 % Na2CO3 solution was added
and made up to 7 ml with distilled water. The tubes were
incubated for 45 min and centrifuged at 2,000 rpm for
10 min at room temperature. The absorbance was read at
765 nm using a UV–Visible spectrophotometer (Shimadzu
corporation, Kyoto, Japan, model UV—1601). The TPC
(mg/100 g) was calculated using gallic acid as standard
compound [18].