I&EC 64 |
| A new method of microwave-assisted extraction (MAE) was evaluated for the extraction of polysaccharides from fruiting bodies of Ganoderma atrum, which have been reported to have medicinal bioactivity. The extracts were directly determined by phenol sulfuric colorimetric method without any further treatment. In the first stage of the microwave extraction process optimization, the single factor experiments as the preliminary trials were performed to evaluate the effects of many related factors on polysaccharides extraction, including irradiation time, temperature, extraction times and ratio of solvent to material. It was found that irradiation time, temperature and ratio of solvent to material significantly affected the extraction of polysaccharides. Subsequently, a uniform experiment design was applied and validated by parallel tests to analyze influences of factors and to further optimize extraction technology. Optimal conditions of MAE of polysaccharides from Ganoderma atrum can be concluded as follows: 5 min at 135ºC , the ratio of solvent to material of 35:1, purified water as the solvent, extraction stages of 2. Experiments on different extraction techniques were also conducted. The results show that MAE method demonstrates several advantages, such as higher extraction yield, less extraction time, lower energy consumption and higher purity of extracts, compared with other extraction techniques including heat reflux, ultrasonic, and enzyme hydrolysis-reflux extraction. The time used in MAE is only 15 min with 6.64% extraction rate, while heat reflux and enzyme hydrolysis-reflux extraction need several hours with only about 2.04% and 3.75% extraction rate respectively. Ultrasonic extraction gives the lightest color of extractive but lowest extraction rate. (Supported financially by the Program for Changjiang Scholars and Innovative Research Team in University (No: IRT0540) and Jiangxi Provincial Department of Science and Technology). |
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IEC Poster Session
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Industrial & Engineering Chemistry |