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Folate and riboflavin producing lactic acid bacteria: isolation and evaluation of their potential application for production of goat dairy products with higher vitamin content.

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Fabiana Fernanda Pacheco da Silva
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
Defense date:
Examining board members:
Bernadette Dora Gombossy de Melo Franco; Cynthia Jurkiewicz Kunigk; Jean Guy Joseph Leblanc; Elaine Cristina Pereira de Martinis; Maristela da Silva do Nascimento
Advisor: Bernadette Dora Gombossy de Melo Franco; Jean Guy Joseph Leblanc

Due to the high nutritional value and physicochemical characteristics, goat milk and cheeses are highly appreciated. Many strains of lactic acid bacteria (LAB) are able to produce vitamins from the B complex, such as riboflavin (B2) and folate (B9). These vitamins have important metabolic roles. The present study aimed to isolate riboflavin- and folate-producing LAB strains from goat milk and cheeses, and evaluate the potential application of those strains in the production of goat dairy products with higher content of these vitamins. A total of 179 LAB isolates were obtained from milk (87) and cheese (92) samples. The isolates were evaluated for production of extra (EC) and intracellular (IC) riboflavin and folate, applying appropriate microbiological methods. Among these isolates, 151 (84.4%) were able to produce folate, while 15 (8.4%) displayed the ability to produce riboflavin, and 14 produced both vitamins. The average production of total folate (EC + IC) was 138.8 µg/L, and the amount of folates produced by 77 isolates (51%) were above this average. The differences observed for the average production of total folate from milk and cheese isolates were statistically significant. For total riboflavin (EC+ IC), the average rate was 363.7 µg/L. Nine isolates (60%) presented production rates above the average. No significant difference was observed between the average production of total riboflafin from milk or cheese isolates (319.3 µg/L and 379.8 µg/L, respectively). Based on RAPD-PCR and 16S rDNA sequencing, 19 different genetic profiles were obtained and 7 species were identified, with predominance of Streptococcus thermophilus (7 isolates), Weissella paramensenteroides (6 isolates), and Lactococcus lactis subsp. lactis (4 isolates). Eight isolates that produced folate above the average were selected and tested for vitamins production in UHT goat milk at 37°C. Seven isolates produced an average of 120.55 µg/L of folate in the milk and concentration varied from 12.97 to 261,91 µg/L. The best folate producers were Lactococcus lactis subsp. lactis FP368, Streptococcus thermophilus FP34v, Streptococcus thermophilus FP170v and Streptococcus thermophilus FP268v. The amount of folate produced by these isolates surpassed the average, and was above the amounts described in other studies, evidencing their potential application in the production of goat dairy products with higher content of folate. None of the tested isolates was able to produce riboflavin in UHT goat milk. (AU)

FAPESP's process: 12/04301-2 - Isolation of lactic acid bacteria producing folate and riboflavin from goat milk and cheese and assessment of their potential application in the elaboration of bioenriched goat dairy products
Grantee:Fabiana Fernanda Pacheco da Silva
Support type: Scholarships in Brazil - Doctorate