Enhancement of radical scavenging activity of quinoa sourdough by lactic acid bacteria fermentation

CECILIA E. MONTES DE OCA; JEAN GUY LEBLANC; A. RODRIGUEZ OLMOS; SILVANA L. CARRIZO; GRACIELA ROLLÁN

San Miguel de Tucuman

Simposio; V Simposio Internacional de Bacterias Lácticas; 2016

CERELA

The Andean quinoa (Chenopodium Quinoa) grain has an excellent nutrient profile and is naturally gluten-free. Several studies have shown that the antioxidant properties of quinoa is in part, due to the presence of bioactive secondary metabolites such as phenolic compounds (PC) which can act as radical scavengers. PC in plants are present as dimers, glycosylated or ester derivatives that do not have biological activity. It has been shown that these compounds are converted into their bioactive form after being subjected to microbial fermentation. The aim of this study was to evaluate the effect of lactic acid bacterial (LAB) fermentation of quinoa dough on its radical scavenging activity. Quinoa doughs (DY=160) were fermented with 18 LAB belonging to the species Lactobacillus (L.) rhamnosus, L. sakei, L. plantarum and Leuconostoc (Leuc.) mesenteroides. These strains were previously isolated from quinoa and amaranth sourdoughs in our laboratory and selected for their important functional activities. Quinoa doughs were inoculated with LAB and incubated for 24 h at 30ᵒC; pH values and CFU/g dough were measured at the beginning and the end of the fermentation. PC concentrations were assayed using the Folin-Ciocalteu test. DPPH and ABTS methods were used to evaluate radical scavenging activity of methanolic extracts obtained from fermented doughs which were evaporated and resuspended in Tris buffer (1M, pH 7). All tested LAB were able to produce an increase in the concentration of PC in quinoa sourdough in contrast with the acidified control (without inoculum). The obtained values have varied between 27.21 μgGAE/100g dough in control and 52.06 μgGAE/100g dough in quinoa sourdough fermented by Leuc. mesenteroides subsp. mesenteroides CRL 2131. Additionally, the quinoa sourdough fermented by this strain produced the highest increase (25%) of radical scavenging activity determined by the ABTS method. Nine strains also showed significant increases (between 9-16%) with respect to the control. The results obtained show the capacity of LAB from ancestral Andean grains to increase the radical scavenging activities. These LAB could be used as starter cultures to obtain novel quinoa based foods with higher antioxidant activity.