Department of Food Engineering, Middle East Technical University, Ankara, 06800 Turkey.
J Food Sci Technol. 2014 Oct;51(10):2776-82. doi: 10.1007/s13197-012-0828-3. Epub 2012 Sep 1.
In this study, extraction of phenolic compounds from nettle by microwave and ultrasound was studied. In both microwave and ultrasound-assisted extractions, effects of extraction time (5-20 min for microwave; 5-30 min for ultrasound) and solid to solvent ratio (1:10, 1:20, and 1:30 g/mL) on total phenolic content (TPC) were investigated. Effects of different powers (50 % and 80 %) were also studied for ultrasound-assisted extraction. In microwave-assisted extraction, the optimum TPC of the extracts (24.64 ± 2.36 mg GAE/g dry material) was obtained in 10 min and at 1:30 solid to solvent ratio. For ultrasound-assisted extraction, the condition that gave the highest TPC (23.86 ± 1.92 mg GAE/g dry material) was 30 min, 1:30 solid to solvent ratio, and 80 % power. Extracts obtained at the optimum conditions of microwave and ultrasound were compared in terms of TPC, antioxidant activity (AA) and concentration of phenolic acids with conventional extraction and maceration, respectively. Microwave reduced extraction time by 67 %. AA of extracts varied between 2.95 ± 0.01 and 4.48 ± 0.03 mg DPPH/g dry material among four methods. Major phenolic compounds were determined as naringenin and chlorogenic acid in nettle.
在这项研究中，研究了微波和超声辅助法从荨麻中提取酚类化合物。在微波和超声辅助提取中，考察了提取时间（微波为 5-20 分钟；超声为 5-30 分钟）和固液比（1:10、1:20 和 1:30 g/mL）对总酚含量（TPC）的影响。还研究了超声辅助提取中不同功率（50%和 80%）的影响。在微波辅助提取中，在 10 分钟和 1:30 的固液比下，提取物的最佳 TPC（24.64±2.36 mg GAE/g 干物质）。对于超声辅助提取，在 30 分钟、1:30 的固液比和 80%的功率下，TPC 最高（23.86±1.92 mg GAE/g 干物质）。比较了微波和超声最佳条件下获得的提取物在 TPC、抗氧化活性（AA）和酚酸浓度方面与常规提取和浸渍法的差异。微波使提取时间缩短了 67%。四种方法的提取物 AA 在 2.95±0.01 和 4.48±0.03 mg DPPH/g 干物质之间变化。主要的酚类化合物被确定为柚皮素和绿原酸。
