Determination of Total Phenolics
Total phenolic contents in extracts were determined according
to the Folin–Ciocalteu procedure (Singlton and Rossi
1965), with slight modifications as follows; 100 mL of the
cherry fruits and fruit jam extracts (triplicate) were transferred
into a test tube and then mixed with 0.4 mL of 10%
Folin–Ciocalteu reagent. After 3 min for allowing the reaction
to take place, 0.8 mL of a 10% Na2CO3 was added. The
tubes were allowed to stand for 1 h at ambient temperature,
and the absorption was measured at 725 nm using spectrophotometer
(CELL, model CE 1020, Cambridge, UK)
against a blank, which contained 100 mL of methanol in
place of the sample. Gallic acid was used as calibration standard,
and the results were calculated as gallic acid equivalent
(GAE) (mg/100 g dry weight basis).