苦瓜籽粗多糖的提取工艺及其体外抗氧化活性

目的: 优化苦瓜籽粗多糖的提取工艺，并对苦瓜籽粗多糖进行体外抗氧化活性研究。方法: 采用水提醇沉法提取苦瓜籽粗多糖，通过苯酚硫酸法测定多糖含量，以多糖提取率为考察指标，考察提取温度、时间、料液比以及提取次数4个因素对苦瓜籽粗多糖提取率的影响。在单因素实验基础上，进行L9（34）正交实验设计，优化苦瓜籽粗多糖的提取工艺。检测苦瓜籽粗多糖对DPPH自由基、羟自由基、超氧阴离子自由基的清除率及总还原能力。结果： 温度是影响苦瓜籽粗多糖提取率的重要因素，确定了最佳提取工艺条件是提取温度为 90 ℃，料液比为 1 ∶30，提取时间为 2.5 h，提取 3次，苦瓜籽粗多糖的提取率为5.61%。苦瓜籽粗多糖对DPPH自由基和羟自由基的清除能力接近于维生素C，而对超氧阴离子自由基清除能力和总还原能力不及维生素C。 结论： 该优化工艺适用于苦瓜籽粗多糖的提取，高浓度苦瓜籽粗多糖具有较好的抗氧化活性。

Extraction and antioxidant activities in vitro of polysaccharides from the seeds of Momordica charantia L

Objective: To study the extraction technology and antioxidant activities in vitro of polysaccharides from the seeds of Momordica charantia L（bitter melon seeds）. Methods: The content of polysaccharides from bitter melon seeds was determined by phenol sulfuric acid method. On the basis of single factors experiments, the four factors including extraction temperature, extraction time, solid liquid ratio and extraction times on the extraction rate of polysaccharides from bitter melon seeds were studied by orthogonal experimental design.DPPH radical, hydroxyl radical,superoxide anion radical and total reduction abilities were used to reflect the antioxidant abilities of polysaccharides.Results: Temperature was an important factor affecting the extraction rate of polysaccharides from bitter melon seeds. The optimal extraction technology conditions were that extraction temperature was 90 ℃, solid liquid ratio was 1 ∶30, the extraction time was 2.5 h, extraction times were 3 times. The extraction rate of polysaccharides were 5.61%. Compared with vitamin C polysaccharides from the seeds of bitter melon had stronger scavenging ability to DPPH radical and hydroxyl radical, but weaker ability to scavenging superoxide anion radical and total reduction ability. Conclusion: This extraction technology is suitable for extraction of polysaccharides from seeds of Momordica charantia L. The polysaccharides have good antioxidant activity at a high concentration.