Bioaccessible Antioxidants in Milk Fermented byBifidobacterium longumsubsp.longumStrains

Abstract

Bifidobacterium longumsubsp.longumis among the dominant species of the human gastrointestinal microbiota and could thus have potential as probiotics. New targets such as antioxidant properties have interest for beneficial effects on health. The objective of this study was to evaluate the bioaccessibility of antioxidants in milk fermented by selectedB. longumsubsp.longumstrains duringin vitrodynamic digestion. The antioxidant capacity of cell extracts from 38 strains, of which 32 belong toB. longumsubsp.longum, was evaluated with the ORAC (oxygen radical absorbance capacity) method. On the basis of screening and gene sequence typing by multilocus locus sequence analysis (MLSA), five strains were chosen for fermenting reconstituted skim milk. Antioxidant capacity varied among the strains tested (P=0.0009). Two strains ofB. longumsubsp.longum(CUETM 172 and 171) showed significantly higher ORAC values than the other bifidobacteria strains. However, there does not appear to be a relationship between gene sequence types and antioxidant capacity. The milk fermented by each of the five strains selected (CUETM 268, 172, 245, 247, or PRO 16-10) did not have higher initial ORAC values compared to the nonfermented milk samples. However, higher bioaccessibility of antioxidants in fermented milk (175–358%) was observed during digestion.