Department of Chemistry, Faculty of Science, Ilam University, Ilam, Iran.
Ultrason Sonochem. 2011 Nov;18(6):1279-86. doi: 10.1016/j.ultsonch.2011.05.004. Epub 2011 May 8.
Ultrasonic technology was applied for extraction of polyphenols and antioxidants from the rice bran using ethanol as a food grade solvent. Response surface methodology (RSM) was used to optimize experimental conditions for extraction of polyphenols and antioxidants. Three independent variables such as solvent percentage (%), temperature (°C) and time (min) were studied. Effect of ethanol concentration was found to be significant on all responses. Total phenolic content (TPC) varied from 2.37 to 6.35mg gallic acid equivalent/g of dry sample. Antioxidant activity of the extracts was determined by the ferric reducing antioxidant power (FRAP) assay and scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. FRAP and DPPH values varied from 31.74 to 57.23μmol Fe(2+)/g of dry sample and 16.88% to 55.61% inhibition, respectively. Extraction yields ranged from 11 to 20.2%. Optimal ultrasonic-assisted extraction (UAE) conditions were identified as 65-67% ethanol, 51-54°C, 40-45min. The experimental values agreed with those predicted by SRM models, thus indicating suitability of the model employed and the success of RSM in optimizing the extraction conditions.
超声技术应用于乙醇作为食品级溶剂从米糠中提取多酚和抗氧化剂。响应面法（RSM）用于优化多酚和抗氧化剂提取的实验条件。研究了溶剂百分比（%）、温度（°C）和时间（min）三个独立变量。发现乙醇浓度对所有响应都有显著影响。总酚含量（TPC）在 2.37 到 6.35mg 没食子酸当量/克干样品之间变化。提取物的抗氧化活性通过铁还原抗氧化能力（FRAP）测定和 1,1-二苯基-2-苦基肼（DPPH）自由基清除活性来确定。FRAP 和 DPPH 值在 31.74 到 57.23μmol Fe（2+）/克干样品和 16.88%到 55.61%抑制之间变化。提取收率在 11%到 20.2%之间。确定了最佳超声辅助提取（UAE）条件为 65-67%乙醇、51-54°C、40-45min。实验值与 SRM 模型预测值吻合，表明所采用模型的适宜性和 RSM 在优化提取条件方面的成功。
