Lactic acid bacteria isolated from amaranth sourdough: technological and functional properties

CARRIZO, S.L.; LAIÑO, J. E.; VIGNOLO, G.; LEBLANC, JEAN GUY; ROLLAN, G.

Congreso; XI Congreso Argentino de Microbiología General; 2015

The pseudocereal amaranth (sp.) is an ancient Andean crop, gluten free (GF), with high nutritional value because 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, shelf- 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 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 activitie 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 produced different levels of this vitamin with L. plantarum A2 M10 9 that produced the highest level of this vitamin (162±19 ng/ml). All isolated strains grew in synthetic medium without B9 and were shown to produce this vitamin in a range between 16 and 138 ng / ml. L. plantarum A2 M10 8 produced the highest concentration of total folates (138±8 ng / ml). From all the tested strains, 73% produced visible ropiness. Six strains of L. plantarum and one E. mundtii produced capsular EPS. Half of the tested strains showed amylolitic activity.These results put in evidence the positive effects of autochthonous LAB isolated from amaranth for the development of healthy novel foods with higher quality and nutritional value.