高粱红色素萃取方法的研究

Study on Extraction Methods for Red Pigment of Sorghum

用索氏萃取法、微波萃取法、超声波萃取法三种方法对比研究了影响提取高粱红色素的各种因素:即溶液的酸碱性、提取温度、时间、功率、液固比。实验结果表明:索氏萃取法的最佳条件为70%体积分数、pH3左右的酸性乙醇,萃取温度75℃,液固比100:1(ml/g),萃取时间240min;微波萃取法溶剂的最佳条件为体积分数70%乙醇,pH2,液固比45:1(ml/g),功率720W,萃取时间1.5min。超声波萃取法的最佳条件为提取温度65℃,功率80W,液固比45:1(ml/g),时间60min。索氏萃取法、微波萃取法、超声波萃取法高粱红色素的产率分别为16.5%、15.03%和13.38%。虽索氏萃取法产率略高于微波萃取法,但综合考虑能耗、萃取时间及操作流程,微波法有省时、快速、节能和节省溶剂等优点。

Effects of different factors, such as acid-base properties, extraction temperature, time, power and the ratio of liquid to solid on extraction of red pigment of sorghum were comparatively investigated by three kinds of methods, i.e., traditional Soxhlet extraction, microwave-assisted extraction and supersonic extraction. The experimental results demonstrated that the optimal conditions for S oxhlet method were 70%（V/V）ethanol, a 3.05 of pH value, ratio of liquid to solid of 100：1 （ml：g）, 75℃ of extraction temperature and extraction time of 240 min, for microwave-assisted extraction were 70%（V/V） ethanol, a 2.0 of pH value, ratio of liquid to solid of 45： 1（ml：g）, 720 watt of power, and extraction time of 1.5 min, and for supersonic extrction were 70%（V/V） ethanol, 65℃ of extraction temperature, 80 watt of power, ratio of liquid to solid of 45：1 （ml：g）, extraction time of 60 min. The yield rate of traditional Soxhlet, microwave-assisted and supersonic extraction are 16.5%, 15.03% and 13.38% respectively. Though the yield rate of traditional Soxhlet is higher than that of microwave-assisted extraction, the microwave-assisted method has many advantages, such as saving time, fast extraction, low energy consumption and solvent saving for synthesis, and simple operation processes.