Evaluation of microbial consortia and chemical changes in spontaneous maize bran fermentation

Abstract

Sustainable exploitation of agro-industrial by-products has attracted great interest in cereal bran valorization. In this research, a polyphasic approach has been carried out to characterize maize bran at microbiological and chemical level during a sourdough like fermentation process, in order to enhance its technological and nutritional properties. Autochthonous microbiota was isolated at different refreshment steps and subjected to identification and molecular characterization. Fermentation was characterized by a rapid increase in lactic acid bacteria and yeasts, with a co-dominance, at the initial stage, of Weissella spp., Pediococcus spp. and Wickerhamomyces anomalus. At the end of the fermentation, a natural selection was produced, with the prevalence of Lactobacillus plantarum, Lactobacillus brevis and Kazachstania unispora. This is the first time that a specific association between LAB and yeasts is reported, during the maize bran fermentation process. Enzymatic activities related to this microbial consortium promoted a “destructuration” of the fiber fraction, an increase in soluble dietary fiber and a reduction of phytic acid content. Our data also evidenced a noticeable increment in ferulic acid. The results obtained indicate that fermentation processes represent an efficient biotechnological approach to increase nutritional and functional potential of maize bran. Moreover, the characterization of microbiota involved in natural fermentation process will allow the selection of specific biotypes, with appropriate metabolic and enzymatic activities, to conduct “tailored” fermentation processes and improve brans or whole-meal flours from both nutritional and technological points of view.

Microbial consortia involved in fermented spelt sourdoughs: dynamics and characterization of yeasts and lactic acid bacteria

“…acidilactici in the final phases dominated the microbial community. These species have been previously reported in sourdoughs made from a range of cereals, including spelt (Van der Meulen et al 2007;Coda et al 2010;Manini et al 2014;Decimo et al 2017). However, our findings highlight the dominance of Ped.…”

“…Total bacterial DNA was extracted from 100 µl of an overnight culture, using the Microlysis kit (Labogen, Rho, Italy) following the manufacturer’s instructions. For yeasts, DNA extraction was performed in a PRECELLYS®24‐DUAL lyser/homogeniser (Bertin‐Technologies, Saint Quentin en Yvelines, France), as previously described (Decimo et al ).…”

“…Total bacterial DNA was extracted from 100 µl of an overnight culture, using the Microlysis kit (Labogen, Rho, Italy) following the manufacturer's instructions. For yeasts, DNA extraction was performed in a PRE-CELLYSâ24-DUAL lyser/homogeniser (Bertin-Technologies, Saint Quentin en Yvelines, France), as previously described (Decimo et al 2017). Molecular identification of LAB isolates with different RSA patterns was carried out using species-specific probes and/or by 16S rRNA gene sequencing.…”

Bakery yeasts, a new model for studies in ecology and evolution

“…Yeast species diversity in sourdough has been well described in Italy, Belgium, and France (Figures 2 and 3, Table S1). We analysed the data obtained for 97 wheat sourdoughs (including possibly also other cereals) described individually (Almeida & Pais, 1996;Corsetti et al, 2001;Decimo, Quattrini, Ricci, Fortina, & Express, 2017;Desiye & Abegaz, 2013;Foschino, Gallina, Andrighetto, Rossetti, & Galli, 2004;Gabriel, Lefebvre, Vayssier, & Faucher, 1999;Garofalo, Silvestri, Aquilanti, & Clementi, 2008;Infantes & Schmidt, 1992;Lacumin et al, 2009;Lattanzi et al, 2013;Lhomme et al, 2015;Lhomme et al, 2016;Mäntynen et al, 1999;Minervini et al, 2015;Obiri-Danso, 1994;Osimani et al, 2009;Pulvirenti, Caggia, Restuccia, Gullo, & Giudici, 2001;Saeed Anjum, Zahoor, Nawaz, & Sajjad-Ur-Rehman, 2009;Salovaara & Savolainen, 1984;Scheirlinck et al, 2007;Spicher & Schröder, 1978;Succi et al 2003;Vrancken et al, 2010;Valmorri, Tofalo, Settanni, Corsetti, & Suzzi, 2010;Zhang et al, 2015;Zhang et al, 2011). S. cerevisiae was found to be present, but not necessarily dominant, in almost 80% of the sourdoughs ( Figure 3).…”

Changes Occurring in Spontaneous Maize Fermentation: An Overview

“…Successively, many authors have reported positive results in the reduction of PI using lactic acid bacteria and yeasts, improving the bioavailability of minerals in fermented maize [135,136]. The reduction of phytic acid by the natural microbiota has also been reported during the fermentation of maize bran by Decimo et al [137]; in this case a reduction of 50% at the end of the sourdough-like fermentation process (corresponding to the twelfth refreshment), was reported.…”