Blueberries as an additive to increase the survival of Lactobacillus johnsonii N6.2 to lyophilisation.

ABSTRACT

Effective cultivation methods, total cost, and biomass preservation are key factors that have a significant impact on the commercialisation and effectiveness of probiotics, such as Lactobacillus. Sugar polymers, milk and whey proteins have been suggested as good additives for industrial preparations. Alternative compounds, such as phytophenols, are a more attractive option, given their potential benefits to human health. The overall goal of this study was to determine if the addition of blueberry phytophenols improves the survival of Lactobacillus johnsonii N6.2 during the freeze-drying process. The addition of blueberry aqueous extract (BAE) stimulated the growth of L. johnsonii under aerobic conditions and improved the stationary phase survival of the bacteria. Furthermore, the addition of BAE to the culture media improved the endurance of L. johnsonii N6.2 to freeze-drying stress, as well as to storage at 4 °C for up to 21 weeks. Moreover, blueberry extract performed more effectively as a lyophilising additive compared to skim milk and microencapsulation with whey protein/sodium alginate. In sum, this study demonstrates that BAE is an effective additive to increase the growth and survival of L. johnsonii N6.2 when added to the culture medium and/or used as a lyophilising preservative. Moreover, BAE or other polyphenols sources might likely enhance growth and increase survival of more probiotic lactic acid bacterial strains.