开菲尔胞外多糖理化性质及其抗氧化特性

Physicochemical properties and antioxidant properties of Kefiran

以开菲尔粒及开菲尔发酵乳为原料提取开菲尔胞外多糖,对其进行理化特性及抗氧化活性的研究。以胞外多糖提取率为指标,通过单因素及正交试验对胞外多糖的提取条件进行优化,并对所得胞外多糖进行扫描电镜、红外光谱、乳化性及抗氧化性等测定。结果表明,开菲尔粒中提取的胞外多糖的边缘为不规则的枝状结构,其上黏附有许多大小形状相似的球形结构,开菲尔发酵乳中提取的胞外多糖结构疏松,呈网状。不同原料提取的胞外多糖的红外光谱峰无明显差异。开菲尔粒中提取的胞外多糖的乳化活性及絮凝活性均优于开菲尔发酵乳中提取的胞外多糖。与开菲尔粒中提取的胞外多糖相比,开菲尔发酵乳中提取的胞外多糖表现出更好的抗氧化活性。由于2种来源的开菲尔胞外多糖在理化性质及抗氧化特性中表现出差异,并结合后期的结构测定,可以为2种来源胞外多糖构效关系的研究奠定理论基础。

Kefiran was extracted from Kefir grains and fermented milk of Kefir,and their physicochemical properties and antioxidant activity were studied.The optimal extraction conditions were obtained by single factor and orthogonal experiments with extraction rate of Kefiran as the index.The obtained Kefiran were tested by scanning electron microscope,infrared spectrum,emulsifying property and antioxidant activity.The edge of Kefiran extracted from Kefir grains was irregular dendritic structure,and many spherical structures with similar size and shape were attached to it.The Kefiran extracted from Kefir fermented milk was loose and reticulate.The infrared spectrum peaks of Kefiran extracted from different raw materials had no obvious difference.The emulsifying activity and flocculation activity of Kefiran extracted from Kefir grains were better than those extracted from Kefir fermented milk.Furthermore,the Kefiran extracted from Kefir fermented milk showed higher antioxidant activity than the Kefiran from Kefir grains.Due to the differences in physicochemical properties and antioxidant properties of Kefiran from the two sources,combined with the later structural determination,it can further lay a theoretical foundation for the study of the structure-activity relationship between the two Kefiran.