Rye bran as fermentation matrix boosts in situ dextran production by Weissella confusa compared to wheat bran

Abstract

The consumption of fiber-rich foods such as cereal bran is highly recommended due to its beneficial health effects. Pre-fermentation of bran with lactic acid bacteria can be used to improve the otherwise impaired flavor and textural qualities of bran-rich products. These positive effects are attributed to enzymatic modification of bran components and the production of functional metabolites like organic acids and exopolysaccharides such as dextrans. The aim of this study was to investigate dextran production in wheat and rye bran by fermentation with two Weissella confusa strains. Bran raw materials were analyzed for their chemical compositions and mineral content. Microbial growth and acidification kinetics were determined from the fermentations. Both strains produced more dextran in rye bran in which the fermentation-induced acidification was slower and the acidification lag phase longer than in wheat bran. Higher dextran production in rye bran is expected to be due to the longer period of optimal pH for dextran synthesis during fermentation. The starch content of wheat bran was higher, which may promote isomaltooligosaccharide formation at the expense of dextran production. W. confusa Cab3 produced slightly higher amounts of dextran than W. confusa VTT E-90392 in all raw materials. Fermentation with W. confusa Cab3 also resulted in lower residual fructose content which has technological relevance. The results indicate that wheat and particularly rye bran are promising matrices for producing technologically significant amounts of dextran, which facilitates the use of nutritionally valuable raw bran in food applications.

In situ synthesis of exopolysaccharides by Leuconostoc spp. and Weissella spp. and their rheological impacts in fava bean flour

“…In detail, the highest cell density increase (Δ log) was observed in 5577_S, and the lowest was in 20240_S. Overall, the addition of sucrose did not significantly affect the final cell density and the cell density increase as already reported in a similar study (Kajala et al, 2015).…”

“…On the contrary, Weissella spp. ferment fructose but do not reduce it to mannitol, leading to low acetic acid production (Galle et al, 2010;Kajala et al, 2015).…”

“…It could be hypothesized that fructose was preferable to glucose for Weissella spp. since different strains might have different carbon source preferences (Kajala et al, 2015).…”

Structure-function relationships of bacterial and enzymatically produced reuterans and dextran in sourdough bread baking application

“…Both studies thus consistently indicate that EPS effects are more pronounced when a strong gluten network is absent. Remarkably, rye bran was recently shown to be an excellent substrate to boost dextran formation by W. cibaria (Kajala et al, 2016). Therefore, dextran-enriched rye or rye bran sourdoughs may serve as functional ingredient in bread production to improve sensory and nutritional properties without compromising texture and volume.…”

The effect of structure and texture on the breakdown pattern during mastication and impacts on in vitro starch digestibility of high fibre rye extrudates

“…Endosperm rye flour (EF) was obtained from Helsingin Mylly (Järvenpää, Finland). Rye bran with high DF content was prepared by milling and air classification of native rye kernels (Jalon Mylly, Kouvola, Finland) with a protocol published by Nikinmaa et al 22,30 Native rye kernels were milled by 100 UPZ-lb fine impact mill (Hosokawa Alpine AG, Germany) using a stainless steel pin discs (17 800 rpm), followed by air classification (speed 3500 rpm, airflow 220 m 3 h −1 , feed rate 50 kg h −1 ) (British Rema Minisplit, Chesterfield, UK). Repeated milling and air classification was performed in order to produce a coarse fraction (34%) of the material.…”