A randomised, double-blind, placebo controlled cross-over study to determine the gastrointestinal effects of consumption of arabinoxylan-oligosaccharides enriched bread in healthy volunteers.

Background: Prebiotics are food ingredients, usually non-digestible oligosaccharides, that are selectively fermented by populations of beneficial gut bacteria. Endoxylanases, altering the naturally present cereal arabinoxylans, are commonly used in the bread industry to improve dough and bread characteristics. Recently, an in situ method has been developed to produce arabinoxylan-oligosaccharides (AXOS) at high levels in breads through the use of a thermophilic endoxylanase.

Consumption of breads containing in situ-produced arabinoxylan oligosaccharides alters gastrointestinal effects in healthy volunteers.

Arabinoxylan oligosaccharides (AXOS) are studied as food compounds with prebiotic potential. Here, the impact of consumption of breads with in situ-produced AXOS on intestinal fermentation and overall gastrointestinal characteristics was evaluated in a completely randomized, double-blind, controlled, cross-over study. Twenty-seven healthy volunteers consumed 180 g of wheat/rye bread with or without in situ-produced AXOS (WR(+) and WR(-), respectively) daily for 3 wk.

Use of psychrophilic xylanases provides insight into the xylanase functionality in bread making.

The bread-improving potential of three psychrophilic xylanases from Pseudoalteromonas haloplanktis TAH3A (XPH), Flavobacterium sp. MSY-2 (rXFH), and unknown bacterial origin (rXyn8) was compared to that of the mesophilic xylanases from Bacillus subtilis (XBS) and Aspergillus aculeatus (XAA). XPH, rXFH, and rXyn8 increased specific bread volumes up to 28%, 18%, and 18%, respectively, while XBS and XAA gave increases of 23% and 12%, respectively.

Structure-based mutagenesis of Penicillium griseofulvum xylanase using computational design.

Penicillium griseofulvum xylanase (PgXynA) belongs to family 11 glycoside hydrolase. It exhibits unique amino acid features but its three-dimensional structure is not known. Based upon the X-ray structure of Penicillium funiculosum xylanase (PfXynC), we generated a three-dimensional model of PgXynA by homology modeling.

Substrate and product hydrolysis specificity in family 11 glycoside hydrolases: an analysis of Penicillium funiculosum and Penicillium griseofulvum xylanases.

Two genes encoding family 11 endo-(1,4)-beta-xylanases from Penicillium griseofulvum (PgXynA) and Penicillium funiculosum (PfXynC) were heterologously expressed in Escherichia coli as glutathione S-transferase fusion proteins, and the recombinant enzymes were purified after affinity chromatography and proteolysis. PgXynA and PfXynC were identical to their native counterparts in terms of molecular mass, pI, N-terminal sequence, optimum pH, and enzymatic activity towards arabinoxylan. Further investigation of the rate and pattern of hydrolysis of PgXynA and PfXynC on wheat soluble arabinoxylan showed the predominant production of xylotriose and xylobiose as end products.

Gluconobacter oxydans NAD-dependent, D-fructose reducing, polyol dehydrogenases activity: screening, medium optimisation and application for enzymatic polyol production.

Gluconobacter oxydans LMG 1489 was selected as the best strain for NAD(P)-dependent polyol dehydrogenase production. The highest enzyme activities were obtained when this strain was cultivated on a medium consisting of 30 g glycerol l(-1), 7.2 g peptone l(-1) and 1.

Potential of selected lactic acid bacteria to produce food compatible antifungal metabolites.

The aim of this study was to assess the potential of lactic acid bacteria to inhibit the outgrowth of some common food-spoiling fungi. Culture supernatants of 17 Lactic acid bacterial strains as well as of three commercial probiotic cultures were evaluated for antifungal activity using an agar-diffusion method. The method parameters were chosen in order to reveal compounds for potential use in food (bio)preservation.