Isolation and identification of potential starter cultures for oat fermentation

Resumen del trabajo presentado al 2nd Forum on Fermented Foods, celebrado en Málaga (España) del 5 al 7 de febrero de 2025.

Oat fermentation using lactic acid bacteria (LAB) is a process leading to numerous nutritional benefits: a lower glycemic index, reduced antinutrient content (e.g. phytic acid), improved digestibility due to hydrolysis of complex carbohydrates, dietary fiber and proteins, enhanced bioavailability of minerals, and better antioxidant properties1, contributing to the mitigation of oxidative stress. Although fermentation can be carried out by commercial starter cultures, innovative starters can be isolated from the proper food matrix, which is of greater interest considering their adaptation to the substrate. This work consisted in isolating, characterizing, and identifying starter cultures from wholegrain oat flour for further fermentation. Isolation was performed by inoculating serial dilutions of oat flour and sourdoughs (200%, dough yield DY) incubated during 16, 21, 24, and 48 h at 32 °C, in different culture media supplemented with cycloheximide and maltose, when required. A total of 123 isolates were characterized as starter cultures based on their ability to acidify oat sourdoughs (200% DY) during 24 h at 32 °C, and typified through amplification of 16S-23S rDNA internal transcribed spacer (ITS). The isolates that exhibited the best acidification properties of fermented oat and different ITS patterns were molecularly identified. Enterococcus faecium species was the most abundant in oat flour while Weissella confusa predominated in sourdoughs. Although the strains of Lactiplantibacillus plantarum and Lactiplantibacillus argentoratensis species were minorly found in both flour and sourdoughs, they showed the best fermentative capabilities in the oat matrix.

This study was funded by PID2022-138978OB-I00 funded by MCIN/AEI/10.13039/501100011033 and “FEDER A way of making Europe”. Maylis Renard thanks the Spanish JAE-intro program funded by CSIC.

Peer reviewed