Bioaccumulation of selenium-by fruit origin lactic acid bacteria in tropical fermented fruit juices

Abstract

Adequate fruit consumption helps to prevent several chronic age-related diseases. Selenium (Se) is an elemental micronutrient with antioxidant capacity. In general, fruits and Se ingest by humans are below the recommended daily intake value. Fresh fruits are highly susceptible to deterioration during storage. Fermentation can improve the storage period, sensory profile, and bioactive compound content of foods; moreover, some lactic acid bacteria can accumulate organic Se intracellularly. In this work, microbial growth and Se accumulation by Levilactobacillus brevis CRL2051 and Fructobacillus tropaeoli CRL2034 in tropical fruit juices were evaluated. The strains could grow 1–2 log cfu/mL, alone or combined, in mango, passion fruit, and mango/passion fruit juices, although they could not completely eliminate native microorganisms in unpasteurised juices. In pasteurised trials, both strains consumed fruit carbohydrates producing lactic acid, in addition to acetic acid, and mannitol by F. tropaeoli. Both strains accumulated Se intracellularly in the fruit juices, especially (123.0 μ g/L) in the passion fruit juice fermented by the mixed culture. Finally, the Fructobacillus strain increased 3.42 times the phenolic compound concentration in the mango/passion fruit juice with added Se after 24 h. The assayed LAB strains could be used for preparing functional fermented fruit beverages bio-enriched in Se.