Lactic Acid Bacteria in Durum Wheat Flour Are Endophytic Components of the Plant during Its Entire Life Cycle

Abstract

bThis study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (a w ) of plant organs. Lactobacilli, showing the highest sensitivity to a w , markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors.

Impact of process conditions on the microbial community dynamics and metabolite production kinetics of teff sourdough fermentations under bakery and laboratory conditions

“…High TTA values reflect high concentrations of lactic acid and acetic acid, thanks to a high buffer capacity of teff flour due to its high ash content, and hence the dominance of mainly heterofermentative LAB species; in turn, they imply high acid tolerance of the dominating LAB and yeast species (Van Kerrebroeck et al., ). Furthermore, batch variations in dominating LAB and yeast species are common during sourdough productions and reflect not only the impact of isolation and identification procedures but also the quality of the flour in terms of age, microbial load, stability, etc ., as well as environmental contamination (De Vuyst et al., , ; Huys, Daniel, & De Vuyst, ; Minervini et al., ). For instance, under the laboratory conditions applied in the study of Moroni et al.…”

Monitoring of wheat lactic acid bacteria from the field until the first step of dough fermentation

“…Berghofer et al (2003) stated that, although the microorganisms that contaminate cereals are more concentrated in the outer layers of kernels and the flour should theoretically contain a lower bacterial load than caryopses, the conditioning phase before milling can increase flour's microbial content. Furthermore, Minervini et al (2015) demonstrated that LAB are also endophytic components of wheat plants. Thus, when they are found in semolina, they probably originate from inner layers of kernels.…”

“…plantarum were only detected after fermentation. Minervini et al (2015) demonstrated that several LAB, including Lb. plantarum, Lb.…”

“…These bacteria have at least a double origin: LAB might be endophytic components of wheat plants (Minervini et al, 2015) or derive from the outer layers of kernels (Berghofer et al, 2003;Gobbetti et al, in press). In the latter case, LAB should derive from the environment.…”

The microbiome of Sardinian barley and malt

“…Minervini and co‐workers reported that Staphylococcus spp. was among the main components of the microbiome in wheat grain.…”