魔芋葡甘聚糖及其衍生物肠道益生性的体外发酵评价

目的:评价魔芋葡甘聚糖(konjac glucomannan,KGM)及其衍生物脱乙酰基魔芋葡甘聚糖(D-KGM)、魔芋葡甘露低聚糖(konjac oligosaccharide,KOS)的肠道益生性。方法:分别以1 g/100 m L的KGM、KOS和D-KGM为碳源,通过小鼠盲肠内容物体外厌氧发酵,测定发酵液的pH值、微生物和短链脂肪酸,评价肠道益生效果。结果:与阳性对照组(以葡萄糖作为碳源)相比,KGM和KOS发酵液pH值明显降低,短链脂肪酸(short-chain fatty acids,SCFAs)和乳酸菌、双歧杆菌的数量显著增加,肠道潜在致病菌(大肠杆菌、梭状杆菌、拟杆菌)的增殖不明显,而D-KGM发酵液中pH值、肠道微生物、SCFAs与阴性对照组(不含碳源)均无显著性差异。结论:KOS和KGM具有显著的肠道益生性,而D-KGM没有肠道益生性。

Evaluation of Prebiotic Functions of Konjac Glucomannan and Its Derivatives by Fermentation in vitro

Objective: To evaluate the prebiotic functions of konjac glucomannan (KGM), konjac oligosaccharides, and
deacetyled konjac glucomannan (D-KGM) in the intestine. Methods: Anaerobic fermentation in vitro with the fresh mouse
cecum contents was carried out using 1 g/100 mL KGM, KOS and D-KGM as carbon sources, respectively. The pH,
bacterial enumeration, and short-chain fatty acids (SCFAs) of the fermented broth were measured. Results: Compared
with the positive control (with GLU as carbon source), the pH of the fermented broths with KGM and KOS was much
lower. Meanwhile, SCFAs, lactobacilli and bifidobacteria increased significantly, while the potentially pathogenic bacteria
(Escherichia coli, Bacterium fusiformis and Bacteroidetes) did not change obviously. The broth of D-KGM presented no
obvious difference compared with the negative control (without carbon source). Conclusion: The prebiotic functions of
KGM and KOS are conspicuous, but D-KGM has no prebiotic function.