Pérez-Ramos Adrián, Mohedano María Luz, López Paloma, Spano Giuseppe, Fiocco Daniela, Russo Pasquale, Capozzi Vittorio
Centro de Investigaciones Biológicas (CIB), CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain.
Department of Agriculture, Food and Environment Sciences, University of Foggia, Via Napoli 25, 71122 Foggia, Italy.
Int J Mol Sci. 2017 Jul 21;18(7):1588. doi: 10.3390/ijms18071588.
Bacterial exopolysaccharides produced by lactic acid bacteria are of increasing interest in the food industry, since they might enhance the technological and functional properties of some edible matrices. In this work, 2.6, which produces an 2-substituted (1,3)-β-d-glucan exopolysaccharide only synthesised by bacteria, was proposed as a starter culture for the production of three cereal-based fermented foods. The obtained fermented matrices were naturally bio-fortified in microbial β-glucans, and used to investigate the prebiotic potential of the bacterial exopolysaccharide by analysing the impact on the survival of a probiotic strain under starvation and gastrointestinal simulated conditions. All of the assays were performed by using as control of the 2.6's performance, the isogenic β-glucan non-producing 2.6NR strain. Our results showed a differential capability of to ferment the cereal flours. During the fermentation step, the β-glucans produced were specifically quantified and their concentration correlated with an increased viscosity of the products. The survival of the model probiotic WCFS1 was improved by the presence of the bacterial β-glucans in oat and rice fermented foods under starvation conditions. The probiotic bacteria showed a significantly higher viability when submitted to a simulated intestinal stress in the oat matrix fermented by the 2.6 strain. Therefore, the cereal flours were a suitable substrate for in situ bio-fortification with the bacterial β-glucan, and these matrices could be used as carriers to enhance the beneficial properties of probiotic bacteria.
乳酸菌产生的细菌胞外多糖在食品工业中越来越受到关注，因为它们可能会增强某些可食用基质的工艺和功能特性。在这项研究中，2.6菌株（它产生一种仅由细菌合成的2-取代的（1,3）-β-d-葡聚糖胞外多糖）被提议作为生产三种谷物基发酵食品的发酵剂。所获得的发酵基质天然富含微生物β-葡聚糖，并通过分析在饥饿和胃肠道模拟条件下对益生菌菌株存活的影响来研究细菌胞外多糖的益生元潜力。所有试验均以不产生β-葡聚糖的同基因2.6NR菌株作为2.6性能的对照进行。我们的结果表明2.6发酵谷物粉的能力存在差异。在发酵步骤中，对产生的β-葡聚糖进行了具体定量，其浓度与产品粘度增加相关。在饥饿条件下，燕麦和大米发酵食品中存在细菌β-葡聚糖可提高模型益生菌WCFS1的存活率。当在由2.6菌株发酵的燕麦基质中经受模拟肠道应激时，益生菌显示出显著更高的活力。因此，谷物粉是用细菌β-葡聚糖进行原位生物强化的合适底物，并且这些基质可以用作载体来增强益生菌的有益特性。
