Functional properties of EPS extract from L. fermentum lf2 and its impact when combined with B. animalis INL1 in yogurt

Abstract

In the present work, the functional roles of an exopolysaccharide (EPS) extract formLactobacillus fermentum Lf2 were studied by means of in vitro and in vivo assays,individually or combined with a probiotic strain, Bifidobacterium animalis subsp. lactisINL1. From the in vitro assay (macrophages derived from THP-1 cell line), the EPS inits purified form caused an increase in the levels of the proinflammatory cytokine TNFα, while both forms of EPS (purified and crude) produced an increase in the regulatorycytokine IL-10, evidencing an immunomodulatory role.To study the functional role of EPS as a food ingredient, an in vivo assay was donewith mice (BALB/c) that received yogurt with EPS (600 mg L-1, YE), with bifidobacteria(5x108 CFU mL-1, YB), a combination of both ingredients (YEB), or yogurt with noadditives (Y), for 25 days. The level of diverse bacterial groups and Short Chain FatyAcids (SCFA) were estimated in faeces, and s-IgA and cytokines were determined insmall intestine. Among the four groups, only the group YE presented significantlyincreased concentrations of acetic and butyric acids, together with an increase in thetotal SCFA (p< 0.05), through the time of treatment. The levels of the C. coccoidescluster (SCFA producing group) rose over time (p< 0.05) for this group as well. Whenthe combination of both ingredients was studied (YEB), a possible bifidogenic role wasobserved, reflected in the increasing levels of the genus Bifidobacterium along time (p<0.05), a behaviour that was not observed when the probiotic was administered solely(group YB). But, in this case, no significant differences were observed for theconcentration of SCFA. These results highlight the promising application of this EPS asa functional food ingredient: with prebiotic or synbiotic potential roles, whenadministered individually (due to its effects on the SCFA levels) or combined with B.animalis subsp. lactis INL1 (considering the increase of Bifidobacteria during the timeof treatment), respectively.