提取方法对黄秋葵花多糖的结构组成及抗氧化活性的影响

以黄秋葵花为原料，研究热水、酸法、酶法、超声辅助提取工艺对黄秋葵花多糖提取率和样品结构组成等 的影响，在此基础上对4 种多糖抗氧化活性进行了比较分析。结果表明：4 种提取方法所得多糖的提取率大小依次 为：酶法提取（（21.90±0.14）%）＞酸法提取（（15.15±0.07）%）＞热水提取（（12.60±0.28）%）＞超声辅 助提取（（12.02±0.37）%）。经酶法和热水提取的多糖样品分子质量较高且特性黏度较大，而超声提取则显著降 低了多糖的分子质量和特性黏度，同时使多糖分子质量的分布更加均一。4 种多糖的单糖组成成分相同，主要包括 鼠李糖、半乳糖醛酸和半乳糖，但单糖的物质的量之比有所不同。傅里叶变换红外光谱分析结果表明，得到的4 种 样品都具有多糖的典型傅里叶变换红外光谱特征。对1,1-二苯基-2-苦基肼自由基清除能力等抗氧化活性的测定结果 表明，4 种多糖具有不同程度的抗氧化活性。其中，以超声辅助提取的多糖抗氧化活性最强。

Effect of Extraction Method on Structure and Antioxidant Activity of Polysaccharides from Okra Flowers

The impacts of four extraction methods (hot water extraction, acid extraction, enzymatic extraction and ultrasonic-assisted extraction) on the yield, structure and antioxidant activities of okra flower polysaccharides were systematically investigated. The results showed that the yield of polysaccharides was in the following decreasing order: enzymatic extraction ((21.90 ± 0.14)%) > acid extraction ((15.15 ± 0.07)%) > hot water extraction ((12.60 ± 0.28)%) > ultrasonic-assistant extraction ((12.02 ± 0.37)%). The polysaccharides extracted by enzyme-assistant extraction and hot water extraction had higher molecular mass and intrinsic viscosity, while ultrasonic-assisted extraction significantly reduced the molecular mass and intrinsic viscosity of polysaccharides and the extracted polysaccharides had a relatively more uniform molecular mass distribution. The polysaccharides obtained by the four extraction methods had identical monosaccharide composition but varied in the molar ratio of monosaccharides, composed mainly of rhamnose, galacturonic acid and galactose. Fourier transform infrared spectroscopy indicated that all four polysaccharides had typical characteristics of polysaccharides. These polysaccharides possessed different antioxidant activities in terms of measurement of 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, with the ones extracted by ultrasonic-assisted extraction showing the strongest antioxidant activity．