Optimization of the Microwave Assisted Extraction of Anthocyanin from Violet Glutinous Rice (<i>Oryza sativa)</i> and its Antioxidant Activities

Abstract

The application of natural pigments like anthocyanin carries substantial implications in various industries due to their health benefits, including antioxidant abilities, limiting resistance reduction and anti-inflammatory activities. This study extracted anthocyanin from violet glutinous rice (VGC) by microwave-assisted extraction (MAE). The process was optimized concerning different extracting parameters such as solvent concentration (H2O, Ethanol 50, 60, and 70%), material-to-solvent ratio (1/5, 1/10, 1/15, 1/20), microwave power (100, 200, 300W) and microwave support time (3, 5, 7, 10 min). Moreover, the antioxidant property of the obtained anthocyanin was investigated using the DPPH (2.2-diphenylpicrylhydrazyl) and ABTS (2,2-azinobis [3-ethylbenzothiazoline- 6-sulphonic acid]) assays. The highest anthocyanin content, 1.572 mg/g, was achieved at the following conditions: 50% ethanol, the solid/liquid ratio (1:10 mL/g), extraction time (5 min), and microwave power (100W). The antioxidant activity of the ethanol extract of violet glutinous rice with values IC50 was achieved at 93.18 µg/ml, and 32.66 µg/ml for DPPH and ABTS scavenging activity, respectively.