Optimizing extraction of functional compounds from Indonesian black rice using response surface methodology

Abstract

This study aimed to determine the optimum extraction condition of anthocyanin, flavonoid, total phenolic content, and antioxidant activity of Jeliteng varieties black rice using the heat-assisted maceration method. Variations in ethanol (50-60%), citric acid (3-5%), and temperature (45-55°C) were studied using a Box–Behnken design. The regression models were statistically significant (P < 0.001) with determination coefficients at ≥0.900. Extraction with ethanol 56.11% and citric acid 4.42% at 49.29°C rendered an extract with 109.64 mg/100 g of anthocyanins, 25.35 mg QE/100 g of flavonoids, 295.56 mg GAE/100 g total phenolic content, and antioxidant activity reached 61.69% of inhibition. Predicted values at the optimized conditions can be confirmed with experimental values.