Fermentation of yam (Dioscorea spp. L.) by indigenous phytase-producing lactic acid bacteria strains

Abstract

The use of lactic bacteria in the development of functional foods has increased in recent years. In addition to their probiotic characteristics, they can ferment a variety of substrates, such as cereals, roots, and tubers. Phytase producer lactic acid bacteria strains and their behavior during the fermentation process of yam-based food were studied. Leuconostoc lactis CCMA 0415, Lactobacillus plantarum CCMA 0744, and Lactobacillus fermentum CCMA 0745 were selected due to phytase production, pH reduction, and growth during 24h of fermentation. Oxalate activity was not detected in all assays, suggesting its concentration was reduced due to the bleaching process. Among the selected strains, L. lactis CCMA 0415 appeared to be a promising strain in yam-based fermentations because it maintained a cell viability above 8 log CFU/mL and did not reduce diosgenin concentrations (around 8.0μg/mL) after fermentation for 24h, thereby, generating a potentially functional yam food. Furthermore, this strain promoted the decrease of pH value from 6.1 to 3.8 and produced 8.1g/L lactic acid, at 6h of fermentation. The L. lactis CCMA 0415 was reported as a starter culture in fermented products based on cereals, roots, and tubers.