Antioxidants from syrah grapes (Vitis vinifera L. cv. Syrah). extraction process through optimization by response surface methodology

Abstract

In this work, optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from Syrah (Sy) wine grapes (Vitis vinifera L. cv. Syrah) using response surface methodology was conducted. The comparisons between two extraction mixtures, Acetone/Water (A/W) as well as Methanol/Water (M/W) and the effects of three critical variables, Extraction Time (between 8 and 88 h), Extraction Temperature (between 1℃ and 35℃) and Solvent Content (between 63% and 97%), on Phenolic Compounds Yield (PCY), Monomeric Anthocyanins Yield (MAY) and the DPPH Free Radical Inhibition Potential (DFRIP) were studied. The highest PCY was obtained in 63% A/W solvent content after 88 h incubation at 35℃. The highest MAY was acquired in 97% M/W solvent content after 8 h incubation at 17℃. The highest DFRIP of the extract was attained using 97% A/W solvent content after 16 h incubation at 35℃. The low cost of this process, on economic and environmental levels, could lead to interesting applications on an industrial scale. It could be used to obtain bioactive phytochemicals from direct material or byproducts for either therapeutic or nutritional purposes.