Production of B-group vitamins by lactic acid bacteria isolated from northwest argentinean pseudocereals

CARRIZO, LORENA; JUAREZ, MARIANELLA; LAÍÑO, JONATAN; LEBLANC, JEAN GUY; VIGNOLO, GRACIELA; ROLLAN, GRACIELA

San Miguel de Tucuman

Simposio; IV International Symposium on Lactic Acid Bacteria: Food, Health and Applications; 2013

CERRELA-CONICET

The pseudocereals quinoa (Chenopodium quinoa) and amaranth (sp.) are ancient Andean crops with high nutritional value because they contain elevated concentrations of proteins, and different levels of vitamins and minerals, in addition to other beneficial compounds such as polyphenols, phytosterols and flavonoids. However, many of these compounds are altered or removed during milling, processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of different foods, thus improving the nutritional value, organoleptic characteristics, self‐ life and overall quality of fermented products. LAB are usually auxotrophic for several vitamins although some strains have the ability to synthesize B vitamins, suggesting that the use of adequately selected strains could increase the concentration of these vitamins in fermented foods and their nutritional value. In previous work, LAB were isolated from spontaneously fermented dough prepared with quinoa and amaranth flours from different sources of Northwestern Argentina (NOA). LAB were identified by biochemical and molecular methods. The aim of this study was to evaluate the production of B vitamins, folate (B9) and riboflavin (B2), by LAB isolated from quinoa and amaranth flour. Thirty‐five strains belonging to the species Lactobacillus (L.) pentosus, L.rhamnosus, L. sakei and L. plantarum were evaluated. LAB were inoculated into a synthetic medium free of vitamin B2 or B9 and incubated at 37° C for 16 h. Intra‐, extracellular and total concentrations of B2 and B9 were determined using a microbiological method with L. rhamnosus ATCC 7469 and L. rhamnosus NCIMB 10463 as the indicator strains. Of the total tested strains, 33 grew on the B2 free medium. L. rhamnosus (5 strains) produced high levels of this vitamin (> 260 ng / ml), whereas L. pentosus produced the highest concentration of intracellular B2 (31.8 ± 0.1 ng / ml), and L. rhamnosus the highest concentration of extracellular B2 (364 ± 0.1 ng/ml). All isolated strains (35) grew in synthetic medium without B9. The total concentration of this vitamin was determined in a range between 16 and 76 ng / ml. L. pentosus produced the highest concentration of extracellular (49.84 ± 0.1 ng / ml) and L rhamnosus the highest concentration of intracellular B9 (30.08 ± 0.1 ng / ml). The results obtained put in evidence that native LAB isolated from quinoa and amaranth from NOA, produce significant levels of vitamin B2 and B9, indicating their potential to be included as starter cultures in pseudocereals containing food preparation with higher nutritional values.