裙带菜中不同分子质量岩藻多糖的理化成分和抗氧化性比较

从中国山东威海海域采收裙带菜（Undaria Pinnatifida）样品，利用乙醇浸提法对样品中的岩藻多糖粗品进行提取。采用透析的方法，制备分子质量小于1×10⁴ u的低分子质量岩藻多糖分离物。测定了不同分子质量岩藻多糖分离物的硫酸盐、糖醛酸及其对1.1-二苯基-2-三硝基苯肼（DPPH）自由基、羟基自由基的清除能力。分析和比较了岩藻多糖粗提取物和分子质量小于1×10⁴ u的岩藻多糖的理化成分和抗氧化活性。分析结果表明：粗提物的硫酸盐和糖醛酸含量略高于低分子质量岩藻多糖，其中粗提物中硫酸盐质量分数高达36.50%。与岩藻多糖粗提物相比，低分子质量岩藻多糖具有更高的一级和二级抗氧化能力。

Comparison of physicochemical constituents and antioxidant properties of fucoidan from different molecular weights of the Undaria pinnatifida

The ethanol extraction method was used to extract fucoidan from the sample of Undaria pinnatifida collected from sea of Weihai, Shandong province, China.The ethanol extraction method was used to extract fucoidan from the samples.Low molecular weight fucoidan isolates with molecular weight less than 1×10⁴u were prepared by dialysis method.The sulfates, uronic acids, and their scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and on hydroxyl radicals of fucoidans with different molecular weight were determined respectively.The physical and chemical constituents and antioxidant activities of the fucoidan crude extracts and fucoidans with molecular weight less than 1×10⁴u were analyzed and compared.The results showed that the sulfate and uronic acid content of the crude extract was slightly higher than that of low molecular weight fucoidan, and the sulfate mass fraction of the crude extracts was as high as 36.50%.Compared with the crude extracts, the fucoidan of low molecular weight has higher primary and secondary antioxidant capacity.