Effect of heat treatment on folate concentration in a B9 naturally bio-enriched yogurts

Abstract

The aim of this work was to study the effect of heat treatment on folate concentration and stability in a B9 naturally bio-enriched yogurt. 3 yogurts were elaborated using B9 producing strains: L. bulgaricus CRL863 & CRL871 and S. thermophilus CRL803 & CRL415. After elaboration, they were heated 3 times at 80ºC for 30 min. After treatment, they were stored at 4ºC. The following were evaluated: a) folate production; b) acidity (pH); c) protein concentration & d) cellular viability (Log CFU/mL). Results: Highest levels of folate were reached after yogurt elaboration. Yogurt B (CRL871 + CRL803 + CRL415) showed the highest folate levels (223.53 ± 2.75 μg/L). In general, pH was about 4.75 and protein concentration ranged from 0.17 to 0.24 g/dL. After heat treatment, only yogurt B had the same folate values (about 220 μg/L). pH and protein levels were not modifi ed by heat. Conclusion: out of the 3 yogurts tested, only B showed folate values 3 times higher than a commercial yogurt. After heat treatment, folate concentration decreased 40% in yogurts A & C, but remained constant in B. It is possible to elaborate and apply heat treatment to yogurts in order to increase their microbiological safety, with no loss of vitamin, depending on the strains used.