Vardakou Maria, Palop Carmen Nueno, Christakopoulos Paul, Faulds Craig B, Gasson Michael A, Narbad Arjan
Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, Norwich, UK.
Int J Food Microbiol. 2008 Mar 31;123(1-2):166-70. doi: 10.1016/j.ijfoodmicro.2007.11.007. Epub 2007 Nov 13.
Dietary supplementation with prebiotics may result in the stimulation of the growth of beneficial bacteria such as lactobacilli and bifidobacteria in the human gastrointestinal tract. The effect of water-unextractable arabinoxylans (WU-AX) derived from wheat on the modulation of gut bacterial composition was investigated using a mixed culture fermentation system. A prebiotic index (PI) score of 2.03 was obtained after addition of 1% (w/v) WU-AX to a pH-controlled stirred anaerobic fermentation vessel. Pretreatment of the WU-AX with endo-beta-1,4-xylanase resulted in significantly higher PI value (3.48) indicating that pretreatment provided oligomers that were better utilised by the gut bacteria. The extracellular hydrolytic enzymes xylanase and ferulic acid esterase are both required for bacterial metabolism of WU-AX and both activities were present in supernatants derived from the mixed batch cultures. Addition of the WU-AX substrates to the batch cultures produced several fold increases of bacterial synthesis of both enzymes, and these increases were greater when the WU-AX substrate was pretreated with xylanase.
膳食补充益生元可能会刺激人体胃肠道中有益细菌（如乳酸菌和双歧杆菌）的生长。使用混合培养发酵系统研究了从小麦中提取的水不溶性阿拉伯木聚糖（WU-AX）对肠道细菌组成的调节作用。在pH值控制的搅拌厌氧发酵容器中添加1%（w/v）的WU-AX后，获得了2.03的益生元指数（PI）评分。用内切-β-1,4-木聚糖酶对WU-AX进行预处理，导致PI值显著更高（3.48），这表明预处理提供的低聚物更易被肠道细菌利用。胞外水解酶木聚糖酶和阿魏酸酯酶都是WU-AX细菌代谢所必需的，且两种酶的活性都存在于混合分批培养物的上清液中。向分批培养物中添加WU-AX底物会使两种酶的细菌合成增加数倍，并且当WU-AX底物用木聚糖酶预处理时，这种增加幅度更大。
