Surface layer properties of dough liquor components: Are they key parameters in gas retention in bread dough?

Gas cell stability during bread making is controlled by both surface and bulk properties. This paper is focused on studying the surface properties of the water-soluble phase of the dough, the dough liquor (with and without lipids), as well as the composition of the air/water interface. Using infrared reflection measurements, we showed that in...

Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materials

Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex process involving the concerted action of...

An explanation for the combined effect of xylanase-glucose oxidase in dough systems

In the bakery industry, glucose oxidase is usually used in combination with xylanase. Although many theories exist on the mechanism of action of each enzyme, the positive effect of combining the two is as yet unexplained. In this paper we studied a possible basis for this synergy by focusing on the involvement of arabinoxylans. Water-extractable...

Interaction of water unextractable solids and xylanase with gluten protein: Effect of wheat cultivar

A previously proposed explanation for the change in gluten properties on addition of pentosans to doughs was based on data for only one wheat cultivar. Using three wheat cultivars, Scipion, Soissons and Amazon, differing in technological quality from weak to strong we have obtained results that support the previous explanation. In addition to...

Evidence that pentosans and xylanase affect the re-agglomeration of the gluten network

In the gluten-starch separation process gluten is formed first as a result of breakdown of the gliadin-glutelin structures during mixing followed by their re-agglomeration. To date the effect of pentosans and enzymes have not been studied separately. A simple modification of TNO Glutomatic system enables pentosans, enzymes, and other materials...

Overproduction of the Aspergillus niger feruloyl esterase for pulp bleaching application

A well-known industrial fungus for enzyme production, Aspergillus niger, was selected to produce the feruloyl esterase FAEA by homologous overexpression for pulp bleaching application. The gpd gene promoter was used to drive FAEA expression. Changing the nature and concentration of the carbon source nature (maltose to glucose; from 2.5 to 60 g l...

Synthesis, processing and export of cytoplasmic endo-ß-1,4-xylanase from barley aleurone during germination

We have identified the major endo-β-l,4-xylanase (XYN-1) in the aleurone of germinating barley grain, and show that it is expressed as a precursor of Mr 61 500 with both N- and C-terminal propeptides. XYN-1 is synthesized as an inactive enzyme in the cytoplasm, and only becomes active at a late stage of germination when the aleurone ceases to...

Effects on chick performance and nutrient digestibility of an endo-xylanase added to a wheat- and rye-based diet in relation to fat source

1. A study with growing chicks investigated the effects of an inclusion of an endo-xylanase preparation (LYXASAN®) to a wheat- and rye-based diet on performance and nutrient digestibility in relation to the fat source. 2. The basal diet contained 500 g wheat and 100 g rye/kg of diet. The basal diet was supplemented with either 65 g soya oil/kg...

Kinetics of mRNA and protein synthesis of genes controlled by the 1,4- β-endoxylanase A promoter in controlled fermentations of Aspergillus awamori

In this study, induction and repression kinetics of the expression of the Aspergillus awamori 1,4-β-endoxylanase A (exlA) gene under defined physiological conditions was analyzed at the mRNA and the protein levels. Induction was analyzed by pulsing D-xylose to a sucrose-limited continuous culture of an A. awamori 1,4-β-endoxylanase A (EXLA)...

An expression system based on the promoter region of the Aspergillus awamori 1,4-bèta-endoxylanase A gene

A new, highly inducible fungal promoter derived from the Aspergillus awamori 1,4-β-endoxylanase A (exlA) gene is described. Induction analysis, carried out with the wild-type strain in shake flasks, showed that exlA expression is regulated at the transcriptional level. Using a β-glucuronidase (uidA) reporter strategy, D-xylose was shown to be an...