Development of a high folate concentration yogurt naturally bio-enriched using selected lactic acid bacteria

Folate concentrations in yogurts vary widely and are normally considered low due to an inadequate selection of starter cultures and fermentation conditions. In this study, folate producing Lactobacillus delbrueckii subsp. bulgaricus (3 strains) and Streptococcus thermophilus (2 strains) were combined and used to elaborate 15 different yogurts. Samples were taken at different time points during the fermentation process and folate concentrations were determined. The yogurt elaborated with strains CRL871 + CRL803 + CRL415 and incubated at 42 °C had significantly higher folate concentrations (reaching 180 ± 10 μg/L) which implies almost a 250% increase in respect to non-fermented milk, and about 125% compared to commercial yogurts. No variations in folate concentration were observed during 28 days of storage at 4 °C. This is the first report of a yogurt naturally bio-enriched in folate using native folate producing starter cultures. •Folate producing strains of L. bulgaricus &S. thermophilus increased folate in yogurt.•Adequate selection of strains increased folate concentration almost 250%.•Folates are best produced at 42 °C using a combination of producer strains.•Folates in bio-enriched yogurts remain stable for at least 28 days at 4 °C.