Screening of autocthonous lactic acid bacteria with the ability to increase the bioactive potential of phytochemicals from andean grains: antioxidant activity

SANDEZ PENIDEZ S.H.; MARTOS G.I.; GEREZ C.L.; LEBLANC J.G.; ROLLÁN G.C.

San Miguel de Tucumán

Congreso; XII Congreso Argentino de Microbiología General. SAMIGE; 2017

Asociación Civil de Microbiología General

Currently there is a global revaluation of pseudocereals (quinoa and amaranth), ancestral Andean grains, due to their high protein content and nutritional value, health benefits, and they do not contain gluten. Pseudocereals are rich in phytochemical compounds: phenolic compounds (PC), alkylresorcinol, lignans, phytosterols and tocopherols, which possess potential antioxidant properties with beneficial effects on consumers´ health. PC in plant substrates are found as dimers, glycosylated linked or derived esters that do not possess biological activities. It has been shown that these compounds can be transformed into bioactive compounds when subjected to a fermentation process. Lactic acid bacteria (LAB), GRAS (Generally Recognized As Safe) microorganisms, form part of the autochthonous microbiota of diverse ecosystems. During fermentation, LAB modify the physicochemical and functional composition of plant substrates by changing the ratio of anti-nutritive / nutritive components. Although fermentation by LAB on different substrates has been well studied, little is known about its effect on gluten-free substrates such as quinoa. At the same time, information regarding the fermentation of pseudocereals by autochthonous LAB and the influence of PC on their growth and antioxidant activity (AOA) is scarce. Based on this, the overall objective of this study was to select autochthonous LAB that can increase the antioxidant activity of bioactive compounds present in quinoa. Growth, acidification capacity, AOA (DPPH and ABTS) and PC (Folin-Ciocolteau) concentrations of 43 LAB strains isolated from sourdoughs and grains of quinoa and amaranth were evaluated. Two controls were carried out without inoculum, C1 and C2, in which the volume of inoculum was replaced with tap water or an acidic solution, respectively. The results allowed the selection of 3 LAB strains: Leuconostoc (Lc.) mesenteroides subsp. mesenteroides CRL 2131, Lactobacillus (L.) plantarum CRL 1973 and CRL 1964. The selected strains increased the AOA from 25 to 31% with respect to C1 and from 6 to 12% with respect to C2 (DPPH method) and from 30 to 36 % with respect to C1 and 19 to 26%, with respect to C2 (ABTS method). The PC concentration increased from 13 to 25 mg GAE / 100 g dough respect to controls. The three strains were used as starter cultures for the production of biscuits with quinoa flour. The results showed that the ability of the 3 LAB strains to increase the AOA and PC content in the food was in line with those obtained in in vitro tests. In conclusion, the 3 selected LAB (Lc. mesenteroides subsp. mesenteroides CRL 2131, L. plantarum CRL 1973 and CRL 1964) possess important characteristics that give them the potential to be used as starter cultures for the design of quinoa-based functional foods.