Aislamiento y caracterización de bacterias ácido lácticas en un fermentado láctico de granos germinados de quinua (Chenopodium quinoa) para potenciales aplicaciones

Abstract

Lactic acid bacteria (LAB) represent a small part of the plant microbiome with the ability to cause changes in the nutritional properties of food. The aim of this work was to isolate and characterize LAB present in germinated native quinoa (Chenopodium quinoa) grains. An optimal germination process for quinoa grains was defined (in 72 hours at 3 temperatures 10, 20 and 35 degrees Celsius), These were used in fermentation. The identification of the best fermentation process was determined by titratable acidity tests, pH, total sugars and LAB quantification at five times (0h, 24h, 48h, 72h and 96h), with and without glucose. Twenty degrees Celsius was defined as the best temperature at the end of 72 hours of germination with 75.67% total germination and 40% germination with a radicle bigger than 0.5 cm. Germinated quinoa grains were obtained for fermentation, the best established treatment was at 37 degrees Celsius for 96 hours of fermentation, characterized by an increase in the concentration of lactic acid (0.561%), a reduction in pH (4.30), and a decrease in the total sugar concentration (0.497%), the maximum growth was 7.27 logarithm of CFU/mL in fermented without glucose. The fermentation of the sprouts with glucose showed a proportional behavior. A fermented product was obtained in accordance with the optimal method, since LAB were isolated and oxidase, catalase, GRAM staining, motility assay, hemolytic, proteolytic and lipolytic activity tests were performed. The tests allowed to confirm metabolic characteristics of this type of bacteria, finally a bank of pure isolates stored under cryopreservation was elaborated. It would be opportune to continue with this study, subjecting the isolates to genotypic identification to be used in different studies such as biotechnological application.