Probiotic and starter cultures as bioproducers of riboflavin: An alternative to chemical enrichment of fermented foods

DE MEDIIROS,I.; BEDANI, R.; ALBUQUERQUE, M.A.C.; LEBLANC, JEAN GUY; GARUTTI,L.; BATTISTINI, C.; SAAD, S.M.I.

Congreso; 30º Congresso Brasileiro de Microbiologia; 2019

The bioenrichment is an interesting alternative to synthetic food fortification, and some strains of lactic acid and probiotic bacteria can produce B group vitamins, such as riboflavin (B2) and folate through a fermentative process. Fruit-processing industries generate by-products that may contain bioactive compounds, like phenolic compounds and fibers, being an interesting ingredient for the development of functional foods. Moreover, it is a sustainable solution for the environmental impact of agro-industrial pomace. This study aimed to evaluate the capacity of strains of Streptococcus thermophilus (ST-M6, TA-40, and TH-4), Bifidobacterium (B.) animalis subsp. lactis (BB-12), B. longum subsp. infantis (BB-02), B. longum (BB-46), Lactobacillus (Lb.) acidophilus (La-5), Lb. fermentum (PCC), Lb. paracasei subsp. paracasei (F-19, L. casei 431), Lb reuteri (RC-14), and Lb. rhamnosus (GR-1, LGG) to produce riboflavin and to ferment fruit by-products. To assess the riboflavin production, each strain was inoculated individually to a culture medium without riboflavin (Riboflavin Assay Medium, RAM), and then incubated at 37 °C for 24 h. The strains that were able to produce vitamin B2 were tested for fermentation (37 °C/ 24 h) of fruit pomace flour from grape (Vitis spp.) and cashew (Anacardium occidentale L.) in modified DeMan, Rogosa and Sharpe (MRS) broth prepared without the addition of carbohydrates and supplemented with each fruit by-product flour (1% w/v). Among the strains tested, Streptococcus thermophilus (ST-M6, TA-40, and TH-04) and the probiotic Lactobacillus fermentum PCC showed potential to produce riboflavin in RAM. Only PCC and ST-M6 were able to ferment the cashew flour, reaching populations of, respectively, 8.25 and 4.82 log CFU / mL. Regarding the fermentation of grape flour, TH-4, TA-40, PCC, and ST-M6 showed populations of, respectively, 6.87, 7.24, 8.40, and 8.38 log CFU/ mL. Therefore, Streptococcus thermophilus strains ST-M6, TH-4, and TA-40 and Lactobacillus fermentum PCC were able to produce riboflavin, and combined with grape by-product, have potential for bio-enriched fermented food production.