论文总字数：27093字

摘 要

　　铁皮石斛作为一种中草药，多糖是它的主要活性成分。本文以铁皮石斛为原料，通过水提、碱提，进一步用DEAE-52纤维素阴离子交换柱和葡聚糖凝胶Sephadex G-100柱分离纯化，获得1种水提多糖WDPE-1、以及3种碱提多糖AEDP-1、AEDP-2、AEDP-3。， 4种多糖的总糖含量在(73.80±0.14)% ～(80.94±0.06) %范围内变化，WEDP-1和AEDP-2的总糖含量高于AEDP-1和AEDP-3；4种多糖的蛋白质含量均低于0.2 %；WEDP-1糖醛酸含量最低，且AEDP-1、AEDP-2、AEDP-3的含量依次增大；WEDP-1还原糖含量比另外3种AEDP高；4种多糖的SO₄^2-含量相似。以石斛多糖为碳源，进行了嗜热链球菌培养实验。结果表明，AEDP-1促进嗜热链球菌生长的最适浓度为3.0%，另外3种多糖为2.0%。4种多糖中，促进作用最强的石斛多糖为AEDP-2。4种多糖主要促进乳酸、乙酸和丙酸的产出，但是产酸量都低于阳性对照的葡萄糖和低聚果糖。本研究为分析石斛多糖促进嗜热链球菌生长的构效关系提供了有用信息。

关键词：铁皮石斛 多糖 嗜热链球菌 发酵 短链脂肪酸

Promoting Effect of Polysaccharides from Dendrobium offcinale on the Growth of Streptococcus thermophilus

Abstract

Dendrobium officinale belong Chinese herbal medicine, Its useful ingredient is polysaccharides. In this paper, D. offcinale was used as raw material. Polysaccharides from D. offcinale were extracted by water and alkali, and further purified by DEAE-52 cellulose anion exchange column and Sephadex G-100 column to obtain a water-extracted polysaccharides WDPE-1, and 3 alkali-extracted polysaccharides AEDP-1, AEDP-2, AEDP-3. The total sugar content of WEDP-1 and AEDP-2 was higher than that of AEDP-1 and AEDP-3, and the four polysaccharides varied from (73.80±0.14) % to (80.94±0.06) %; the protein content was less than 0.2 %; the uronic acid content of the alkali-extracted polysaccharides was much higher than that of the water-extracted polysaccharides, and the uronic acid content of AEDP-1, AEDP-2 and AEDP-3 increased in turn; WEDP-1 reducing sugar content is higher than the other three AEDP; the SO₄^2- content of the four polysaccharides was similar. The culture experiment of Streptococcus thermophilus was carried out using polysaccharides from D. offcinale as carbon source. The optimum concentration of AEDP-1 for promoting the growth of S. thermophilus was 3.0 %, and the other three polysaccharides were 2.0 %. Among the four polysaccharides, the most promoted polysaccharides was AEDP-2. The four polysaccharides mainly promoted the production of lactic acid, the acetic acid and propionic acid, the acid production was lower than that of positive control glucose and oligofructose. This study offered Valid information to analyzing the structure-activity connection of polysaccharides from D. offcinale to promote the growth of S. thermophilus.

Key Words: Dendrobium offcinale; Polysaccharides; Streptococcus thermophilus; Fermentation; Short-chain fatty acid

目 录

摘要 Ⅰ

ABSTRACT Ⅱ

第一章 绪论 1

1.1 石斛多糖的理化特性和生物活性 1

1.1.1 理化特性 1

1.1.2 生物活性 1

1.2 益生菌 2

1.2.1 益生菌的定义与分类 2

1.2.2 乳酸菌的益生作用 2

1.2.3 嗜热链球菌的生理特性 2

1.3 多糖的益生元作用 3

1.3.1 益生元的定义与分类 3

1.3.2 乳酸菌生长促进作用 3

1.3.3 乳酸菌产酸促进作用 3

1.4 现有研究中存在的问题 4

1.5 本研究的目的及意义 4

1.5.1 研究目的 4

1.5.2 研究意义 4

1.6 研究内容 4

第二章 实验材料与方法 6

2.1 实验材料与仪器 6

2.1.1 铁皮石斛 6

2.1.2 仪器和试剂 6

2.2 实验方法 7

2.2.1 粗多糖的制备 7

2.2.2 多糖的分离和纯化 7

2.2.3 多糖样品的理化分析 8

2.2.4 嗜热链球菌培养 13

2.2.5 嗜热链球菌生长及产酸能力测定 14

第三章 结果与讨论 16

3.1 多糖洗脱曲线 16

3.1.1 DEAE-52纤维素阴离子交换柱的多糖洗脱曲线 16

3.1.2 Sephadex G100凝胶柱的多糖洗脱曲线 16

3.2 多糖制品的化学成分 18

3.3 石斛多糖对嗜热链球菌生长的影响 18

3.4 石斛多糖对嗜热链球菌产酸的影响 19

第四章 结论与展望 23

4.1 结论 23

4.2 展望 23

参考文献 24

致谢 29

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