Folate production by lactobacillus spp. in co-culture with streptococcus thermophillus in soymilk supplemented with fruit by-product and fructooligosaccharides

ALBUQUERQUE, M.A.C.; SAAD, S.M.I.; BEDANI, R.; LEBLANC, JEAN GUY

Amsterdam

Conferencia; 5th Beneficial Microbes Conference; 2016

Beneficial Microbes

Some starter and probiotic cultures may be used for delivering B-group vitamins in fermented foods, such as fermented soy products, enhancing their nutritional and functional values. Therefore, the potential of two Streptococcus thermophilus (ST-M6 and TH-4) and two probiotic lactobacilli strains (Lb. acidophilus LA-5 and Lb. rhamnosus LGG) to produce natural folates in co-culture during the fermentation of four formulations of soymilk (F1: soymilk (SM); F2: SM with 1% (m/v) of passion fruit by-product (PFBP); F3: SM with 1% of fructooligosaccharides (FOS); F4: SM with 0.5% of PFBP and 0.5% of FOS) was investigated. Before fermentation, each formulation was inoculated with 4-5 log cfu/ml of each strain in co-culture (ST-M6+LA-5, ST-M6+LGG, TH-4+LA-5, TH-4+LGG) and incubated statically at 37 °C for 24 h. The folate content of each formulation was determined at 0 and 24h by microbiological assay. The four co-cultures were able to increase the folate level of each fermented soymilk formulation. Regarding F1 (134±19 ng/mL), the combination TH-4+LA-5 produced the highest amount of the vitamin (1092±42 ng/mL) and the lowest was produced by TH-4+LGG (683±25 ng/mL); in F2 (177±45 ng/mL), the best producer was TH-4+LGG (1170±93 ng/mL) and the lowest was ST-M6+LA-5 (526±25 ng/mL); in F3 (149±44 ng/mL), the combination TH-4+LA-5 (1432±24 ng/mL) was the best producer and ST-M6+LGG (1210+23 ng/mL) produced the lowest level. The combination TH-4+LGG produced the highest folate value in F4 (from 156±31 to 1927±49 ng/mL) and the lowest production was obtained by ST-M6+LA-5 (1110±50 ng/mL). The use of lactobacili in co-culture with streptococci increased considerably the initial folate value of each soymilk formulation and the production was co-culture-dependent. Besides, the PFBY and FOS also influenced the folate production by the microorganisms and the highest levels were observed in F3 and F4. Thus, the tested co-cultures may be used to develop new synbiotic fermented soy foods bio-enriched with natural folates.