Optimization of Extraction Conditions of Betacyanine from Red Beet Using Supercritical Fluid by Response Surface Methodology

Optimization of extraction conditions of bioactive compounds from red beet (Beta vulgaris) was performed using response surface methodology. For this purpose, three independent variables were temperature (40, 60, and 80 °C), time (20, 40, and 60 min) and pressure (90, 135 and 180 bar) for modeling and then optimization using Box–Behnken design. Optimization of extraction conditions was determined based on maximum extraction efficiency, maximum total phenolic content, maximum betacyanine content, and lowest IC50 index. The results showed that increasing the temperature (from 40 to 80 °C), time (from 20 to 60 min), and pressure (from 90 to 135 bar) increased extraction efficiency significantly (p<0.05). Also, increasing the pressure from 90 to 135 bar, the temperature from 40 to 60 °C and the extraction time from 20 to 60 min significantly increased total phenolic content, antioxidant activity and betacyanine content of the extract (p<0.05). For red beet extract, the optimum conditions for supercritical carbon dioxide extraction were 58.74 °C and 60 minutes of extraction at 133.99 bar.Under these conditions, extraction efficiency was 1.87, phenolic compounds were 35.67, antioxidant activity was 0.12, and betacyanine content was 3.34.