谷子可溶性膳食纤维的理化性质、结构表征及对7种肠道菌群体外生长的影响

Physical and Chemical Properties and Structural Characterization of Soluble Dietary Fiber from Millet and Its Effects on the Growth of Seven Kinds of Intestinal Bacteria in Vitro

采用酶法提取谷子中的可溶性膳食纤维(SDF),测定SDF的持油力、溶解度及其对胆固醇和NO_(2)-的吸附能力等理化性质,研究SDF的单糖组成、分子质量,同时分析SDF对植物乳杆菌、鼠李糖乳杆菌、发酵乳杆菌、嗜酸乳杆菌、短双歧杆菌、大肠杆菌、金黄色葡萄球菌7种肠道菌群生长的影响。结果显示:SDF的持油力为4.05 g/g,溶解度1.78 g/100 mL;在pH 2.0时,SDF对胆固醇的吸附作用为16.22μg/g,对NO_(2)-的吸附能力为6.97μg/g;在pH 7.0时,SDF对胆固醇的吸附能力为26.31μg/g,对NO_(2)-的吸附能力为2.77μg/g。红外光谱分析表明SDF具有典型的多糖特征。色谱法分析表明SDF是一种分子质量为1784 u的杂多糖,由岩藻糖、阿拉伯糖、半乳糖、葡萄糖、甘露糖、葡萄糖醛酸6种单糖构成,它们的物质的量比分别为0.02∶0.27∶0.26∶98.34∶0.95∶0.15。SDF在质量浓度5~20 mg/mL范围,对植物乳杆菌、鼠李糖乳杆菌、发酵乳杆菌、嗜酸乳杆菌、短双歧杆菌有显著的促进作用,对大肠杆菌和金黄色葡萄球菌有显著的抑制作用,且均呈现浓度依赖性。此外,与对照相比,在培养基中添加SDF,可显著降低pH值,有利于肠道中有益微生物的生长、繁殖。本试验结果可为进一步研究谷子SDF,开发利用谷子资源提供理论参考。

In this experiment,soluble dietary fiber(SDF)was extracted from millet by enzymatic method.The oil holding capacity,solubility and adsorption of cholesterol and NO_(2)-of SDF were determined,and the monosaccharide composition and molecular weight of SDF were studied.At the same time,the effects of SDF on the growth of Lactobacillus plantarum,Lactobacillus rhamnosus,Lactobacillus fermentans,Lactobacillus acidophilus,Bifidobacterium brevis,Escherichia coli and Staphylococcus aureus were analyzed.The results showed that the oil holding capacity and solubility of SDF were 4.05 g/g and 1.78 g/100mL.When pH was 2.0,the adsorption capacity of SDF for cholesterol and NO_(2)-was 16.22μg/g and 6.97μg/g respectively.At pH 7.0,the adsorption capacity of SDF for cholesterol and NO_(2)-was 26.31μg/g and 2.77μg/g respectively.Infrared spectrum analysis showed that SDF had typical polysaccharide characteristics.Chromatography showed that SDF was a heteropolysaccharide with a molecular weight of 1784 u.SDF was composed of fucose,arabinose,galactose,glucose,mannose and glucuronic acid with a molar ratio of 0.02∶0.27∶0.26∶98.34∶0.95∶0.15,respectively.In the range of 5~20 mg/mL,SDF showed significant promoting effects on Lactobacillus plantarum,Lactobacillus rhanosus,Lactobacillus fermentans,Lactobacillus acidophilus,and Bifidobacterium brevis,and showed significant inhibitory effects on Escherichia coli and Staphylococcus aureus in a concentration dependent manner.In addition,SDF added to the medium significantly reduced pH compared to the control,which was conducive to the growth and reproduction of beneficial microorganisms in the gut.The results of this experiment can provide a theoretical basis for further study of SDF and development and utilization of millet resources.