Extraction and characterization of phenolic content from purple and black rice (Oryza sativa L) bran and its antioxidant activity
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The extraction process of phenolic contents from black and purple rice bran in acetone, ethanol, and water, was optimized using rotatable central composite design (RCCD). Results of the study suggested that ethanol was the most efficient solvent to extract total phenolic content (TPC) from rice bran. The optimal condition for extraction of TPC from purple rice bran was, 43.74% (v/v) ethanol concentration, 37.5 °C temperature, 22.5 min extraction time and 8.75 (mL/g) solvent to solid ratio. Whereas, for black rice bran, except solvent to solid ratio (8.80 mL/g), the optimal condition was same as purple rice bran. TPC was found to be higher in purple rice bran extract than black rice bran extracts at optimum condition. RCCD data was successfully used to predict the extraction yield using the artificial neural network. The purple rice bran extract shows a promisingly higher amount of phytochemical content in term of TPC, flavonoid, anthocyanins and phenolic acid than black rice bran extract. The purple rice bran extract also showed the higher antioxidant activity than black rice bran extract.
KeywordsRice bran Extraction Phenolic compounds Anthocyanin Antioxidant activity
The authors are grateful to the Indian Institute of Technology Guwahati and Tezpur University for technical support.
- 23.R.H. Myers, D.C. Montgomery, C.M. Anderson-Cook, Response Surface Methodology: Process and Product Optimization Using Designed Experiments, 4th edn. (Wiley, Hoboken, 2016), p. 728Google Scholar