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Optimization of extraction conditions of flavonoids from wheat flour using response surface methodology

The optimum conditions for the extraction of total flavonoids from wheat flour with different mineral content (T-550, T-850 and T 1100) were determined using response surface methodology. A Box Behnken design was used to investigate the effects of solvent concentration (30-70% aqueous ethanol), extraction temperature (30 90 °C) and time (20-60 min) as well as their interaction on the extractability of total flavonoids. The Box Behnken design consisted of 15 experimental runs for each sample with three replications at the centre point. Data were analyzed using Design Expert software 7.1.6. The total flavonoids content was measured using the aluminium chloride colorimetric assay at 510 nm and results were expressed as (+) catechin equivalent per a dry basis of wheat flour (mgCE/gdb). To predict total flavonoids content a second-order polynomial model was used. The experimental results fitted well to the models where more than 91% of the variability was explained. The optimal conditions for total flavonoids content obtained using numerical optimization within the experimental range of the variables studied were at 70% aqueous ethanol, 30 °C and 20 minutes. At this condition, the predicted response values for total flavonoids content of wheat flour T 550, T-850 and T 1100 were 0.18 mgCE/gdb, 0.15 mgCE/gdb and 0.19 mgCE/gdb, respectively.

optimization of extraction; response surface methodology; wheat flour; total flavonoids

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