Department of Food and Nutritional Sciences, University of Reading, Reading, RG6 6AP, United Kingdom.
Nutr J. 2012 Jun 1;11:36. doi: 10.1186/1475-2891-11-36.
Prebiotics are food ingredients, usually non-digestible oligosaccharides, that are selectively fermented by populations of beneficial gut bacteria. Endoxylanases, altering the naturally present cereal arabinoxylans, are commonly used in the bread industry to improve dough and bread characteristics. Recently, an in situ method has been developed to produce arabinoxylan-oligosaccharides (AXOS) at high levels in breads through the use of a thermophilic endoxylanase. AXOS have demonstrated potentially prebiotic properties in that they have been observed to lead to beneficial shifts in the microbiota in vitro and in murine, poultry and human studies.
A double-blind, placebo controlled human intervention study was undertaken with 40 healthy adult volunteers to assess the impact of consumption of breads with in situ produced AXOS (containing 2.2 g AXOS) compared to non-endoxylanase treated breads. Volatile fatty acid concentrations in faeces were assessed and fluorescence in situ hybridisation was used to assess changes in gut microbial groups. Secretory immunoglobulin A (sIgA) levels in saliva were also measured.
Consumption of AXOS-enriched breads led to increased faecal butyrate and a trend for reduced iso-valerate and fatty acids associated with protein fermentation. Faecal levels of bifidobacteria increased following initial control breads and remained elevated throughout the study. Lactobacilli levels were elevated following both placebo and AXOS-breads. No changes in salivary secretory IgA levels were observed during the study. Furthermore, no adverse effects on gastrointestinal symptoms were reported during AXOS-bread intake.
AXOS-breads led to a potentially beneficial shift in fermentation end products and are well tolerated.
益生元是食物成分，通常是非可消化的低聚糖，被有益的肠道细菌选择性发酵。内切木聚糖酶常用于面包工业，以改变天然存在的谷物阿拉伯木聚糖，从而改善面团和面包特性。最近，开发了一种原位方法，通过使用嗜热内切木聚糖酶在面包中高水平生产阿拉伯木聚糖低聚糖（AXOS）。AXOS 已被证明具有潜在的益生元特性，因为它们在体外和在鼠类、禽类和人类研究中观察到对微生物群有益的变化。
对 40 名健康成年志愿者进行了一项双盲、安慰剂对照的人体干预研究，以评估与非内切木聚糖酶处理的面包相比，食用原位产生的 AXOS（含 2.2 g AXOS）的面包对人体的影响。评估粪便中挥发性脂肪酸的浓度，并使用荧光原位杂交技术评估肠道微生物群的变化。还测量唾液中分泌型免疫球蛋白 A（sIgA）的水平。
食用富含 AXOS 的面包可增加粪便中的丁酸，且趋势为降低异戊酸和与蛋白质发酵相关的脂肪酸。在最初食用对照面包后，粪便中双歧杆菌的水平增加，并在整个研究期间保持升高。食用安慰剂和 AXOS 面包后，乳酸杆菌的水平升高。在研究期间，唾液分泌型免疫球蛋白 A 水平没有变化。此外，在摄入 AXOS 面包期间，没有报告对胃肠道症状有任何不良影响。
AXOS 面包导致发酵终产物的潜在有益变化，并且耐受性良好。
