Total polyphenols
Whole meal flour (150 g) of each accession were
extracted with 150 mL of a mixture of CH3
OH/H2
O/
HCOOH (50:48.5:1.5) for 24 h at room temperature.
The mixture was centrifuged at 2500 g for 15 min
and the supernatant was collected and stored at 4°C
(Gómez-Alonso et al., 2007). Total polyphenols were
assayed using the Folin–Ciocalteau method (AguilarGarcia
et al., 2007). Briefly, Folin-Ciocalteau reagent
was diluted with water 1:9 (v/v). To 2.5 mL of this
reagent, 60 µL of the sample extract was added and
after 2 min incubation at room temperature, 2 mL
sodium carbonate solution (75 g/L) was added. The
mixture was incubated for 15 min at 50°C and cooled
quickly in an ice-water bath. The absorbance at 760
nm was read within 15 min by spectrophotometer
(Libra S22, Biochrom, England). The standard curve
was made using gallic acid. The obtained regression
equation was y = 2.4646x-0.0228, (R2
= 0.9967)