Fermentation of quinoa and wheat slurries by Lactobacillus plantarum CRL 778: proteolytic activity

Abstract

Quinoa fermentation by lactic acid bacteria (LAB) is an interesting alternative to produce new bakery products with high nutritional value; furthermore, they are suitable for celiac patients because this pseudocereal contains no gluten. Growth and lactic acid production during slurry fermentations by Lactobacillus plantarum CRL 778 were greater in quinoa (9.8 log cfu/mL, 23.1 g/L) than in wheat (8.9 log cfu/mL, 13.9 g/L). Lactic fermentation indirectly stimulated flour protein hydrolysis by endogenous proteases of both slurries. However, quinoa protein hydrolysis was faster reaching 40-100% at 8 h of incubation while wheat protein hydrolysis was only 0-20%. In addition, a higher amount of peptides (24) and free amino acids (5g/L) were determined in quinoa compared to wheat. Consequently, greater concentrations (ca. 2.6-folds) of the antifungal compounds (phenyllactic and hydroxyphenyllactic acids) were synthesized from Phe and Tyr in quinoa by L. plantarum CRL 778, an antifungal strain. These promising results suggest this LAB strain could be used in the formulation of quinoa sourdough to obtain baked goods with improved nutritional quality and shelf life, suitable for celiac patients.