Aplicação de novas cepas de Lactobacillus spp. como cultura iniciadora na produção de fermento natural fresco e liofilizado e seus impactos na produção e qualidade de pães de longa fermentação

Abstract

Mature sourdough composes a rich and diverse microbiota, mainly of lactic acid bacteria (LAB) and yeast. Its secondary metabolites are responsible for conferring technological properties on sourdough and long-fermentation breads. The biochemical transformations that occur at all stages, from its preparation, passing through propagation, and, finally, through its use in the production of long-fermentation breads, have an impact on the production of breads with sensory and quality characteristics that differentiate it from traditional bread. Dehydrated sourdough aims to minimize production, storage and logistics costs on a large scale, actions that are difficult when sourdough is used in its fresh form and enable the production of long-fermentation breads. Therefore, the study was divided into two stages. In the first stage, five strains of Lactobacillus spp. as starter cultures in the production and propagation of sourdough, using wheat flour and water as substrates. For the production of sourdough, three strains were selected that showed the best results according to the applied protocols (Limosilactobacillus fermentum 56, Lactiplantibacillus pentosus 129 and Limosilactobacillus fermentum 139). The sourdoughs showed stable microbiota and characteristic pH after 10 days of propagation. Immediately after maturation, the breads were prepared with their respective fresh sourdoughs and presented satisfactory technological and quality characteristics during storage, mainly in the breads produced from the inoculation of strains of L. pentosus 129 and L. fermentum 139 as starter cultures of sourdough. The freeze-dried of sourdoughs were part of the second stage of this study and aimed to produce sourdough with L. pentosus 129 and L. fermentum 139 strains in a single culture or co-culture, evaluate their stability during 60-day storage and produce long-fermentation breads as the final product obtained (dehydrated sourdough). During storage, the freeze-dried sourdoughs showed excellent stability (microbiological and physical-chemical) and high viable cell counts (between 6 – 8 log CFU/g) which was confirmed by flow cytometry (> 70%). Among the samples of freeze-dried sourdough and their respective breads, the bread produced with freeze-dried sourdough with the strain L. fermentum 139 showed the best results in the evaluated parameters (texture, specific volume, and protein digestibility in vitro). An intellectual property request was made for the freeze-dried sourdough inoculated with the L. fermentum 139 strain. Finally, based on the results obtained it was possible to produce freeze-dried sourdoughs from Lactiplantibacillus pentosus 129 and Limosilactobacillus fermentum 139 strains with technological characteristics similar to fresh sourdough and with leavening activity that eliminates the use of baker's yeast that act in the rapid fermentation and production of gases necessary for the increase in bread volume.