Lactic acid bacteria isolated from amaranto sourdough: technological and functional properties.

CARRIZO; S.L.; LAIÑO;J;; VIGNOLO; G.; LEBLANC, G. J;; ROLLÁN, G

Córdoba

Congreso; XI Congreso Argentino de Microbiología General-Samige; 2015

The pseudocereal amaranth (Amaranthus sp.) is an ancient Andean crop, gluten free (GF), with high nutritional value, higher than that of most cereal grains, owing to its high protein content and balanced essential amino acid composition.. Moreover, amaranth grain protein is rich in lysine, which is usually deficient in cereal grains. Also, these grains contain 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 in our laboratory, LAB were isolated from spontaneously fermented dough prepared with amaranth flours from Northwestern Argentina (NOA). LAB were identified by biochemical and molecular methods. The aim of this study was to evaluate technological and functional properties: ropiness, capsular EPS (CPS), vitamin B2 (riboflavin) and B9 (folate) production and amylolytic activity of LAB isolated from amaranth sourdough. Fifteen strains belonging to the species Lactobacillus (L.) plantarum, L. rhamnosus, and Enterococcus (E.) mundtii were evaluated. Intra, extracellular and total concentrations of B2 and B9 were determined using microbiological methods. The CPS formation was determined by the India ink negative-staining technique. The production of ropiness was assessed by visual observation of the elevation of colonies by touching them with sterile toothpick and by their mucoid aspect. The results showed that of the total tested strains, 14 grew on the B2 free medium and the B2 production was variable, L. plantarum A2 M10 9 produced the highest concentration of this vitamin (162,7±19 ng/ml). All isolated strains grew in synthetic medium without B9 and shown to produce this vitamin in a range between 16 and 138 ng / ml. L. plantarum A2 M6 3 produced the highest concentration of intracellular (7,2±0,1 ng / ml). From all the tested strains, 73% produced visible ropiness. Six strains of L. plantarum and one of E. mundtii produced CPS. Respect to amylolitic activity, 50% of the evaluated strains showed capacity to hydrolyze the amaranth starch. The majority of L. plantarum strains isolated from amaranth sourdough demonstrated capacity to produce ropiness and amilolytic activity.These results put in evidence the positive effects of autochthonous LAB isolated from amaranth sourdough for the development of healthy novel foods with higher quality and nutritional value.