超声波辅助双水相提取银耳多糖的工艺优化及其抗氧化活性
Optimization of Ultrasonic-Assisted Aqueous Two-Phase Extraction Conditions of Polysaccharides from Tremella fuciformis and Its Antioxidant Activity

目的：对银耳的多糖进行超声辅助双水相提取，结合响应面法进行工艺提取优化，并对提取到的银耳多糖是否具有体外抗氧化活性进行研究。方法：以古田银耳为原料，以双水相作为提取方法，采用超声辅助技术提取银耳中的多糖。通过单因素实验和响应面分析技术对提取过程进行了工艺优化。从DPPH自由基清除率、羟基自由基的清除率和ABTS⁺自由基的清除率，来探讨多糖在体外的自由基清除能力。结果：以乙醇–硫酸铵组成的双水相体系，在超声萃取时间为30 min、乙醇的质量分数24.68%和硫酸铵的质量分数28%、银耳粉加入量为5.6 mg，此时银耳多糖得率最高为70.43 ± 0.3 mg/g。提取的银耳多糖的羟基自由基、DPPH、ABTS⁺自由基清除率IC₅₀分别为0.23、4.49、0.81 mg/mL。结论：采用超声辅助双水相提取古田银耳多糖，含量高，均具有抗氧化活性。
Objective: To optimize the extraction process and to investigate whether polysaccharids from Tremella fuciformis have antioxidant activity in vitro, Polysaccharide from Tremella fuciformis were extracted by ultrasonic-assisted aqueous two-phase extraction combined with response surface methodology. Methods: Ultrasonic-assisted aqueous two-phase extraction technology was used to extract polysaccharids from Gutian Tremella fuciformis. Single factorial experiments and response surface methodology optimized the extraction process. The in vitro antioxidant activity of polysaccharids was evaluated in terms of the rate of scavenging of DPPH radicals, the rate of scavenging ABTS⁺ free radicals and the rate of scavenging of hydroxyl radicals. Results: Under the aqueous two-phase system constructed by ethanol-(NH₄)₂SO₄, the time of ultrasonic was 30 minutes, the mass content of ethanol and (NH₄)₂SO₄ was 24.68%, 28% and the addition amount of Tremella fuciformis powder was 5.6 mg. The highest yield of Tremella fuciformis polysaccharide was 70.43 ± 0.3 mg/g. The IC₅₀ scavenging rates of hydroxyl, DPPH, and ABTS⁺ free radicals of the extracted Tremella fuciformis polysaccharides were 0.23, 4.49, and 0.81 mg/mL, respectively. Conclusion: Ultrasound-assisted aqueous two-phase extraction of polysaccharides from Gutian Tremella fuciformis has high content, antioxidant activity.