A multi-step process for an alternative wheat bran biorefinery

BARCELON

Extraction by three processes of arabinoxylans from wheat bran and characterization of the fractions obtained

Arabinoxylans (AXs) were extracted from destarched wheat bran (DWB) according to different processes, with a view to their production at industrial scale. Two fractions (F3a and F3b, respectively purified on 10 kDa and 100 kDa ultrafiltration membranes) were obtained with low yields by treating DWB with an endoxylanase and this process left a solid residue exhausted in enzyme-extractable AXs (EDWB). F1 and F2 AX fractions were obtained by treatment with sodium hydroxide of respectively DWB and EDWB. The fraction F4 resulted from a hydrothermal treatment of EDWB in a pressure reactor, followed by ethanol precipitation. The different AX fractions were characterized and compared for the composition in monosaccharides, for the contents in fats and in ferulic, phytic and uronic acids, for the molecular mass distribution and the degrees of methylation and acetylation. The alkaline extractions gave one desesterified AX population with molecular mass (MM) higher than 670 kDa and arabinose/xylose ratios (Ara/Xyl) around 1. The enzyme and thermal treatments yielded AXs with two main populations in size-exclusion chromatography (the largest one at 5-12.5 kDa and a second one at 140-160 kDa), having overall Ara/Xyl of respectively 0.7 and 0.5 for both processes. These data bring information about the influence of the process on the characteristics of AX fractions obtained from pretreated wheat bran. Here are also reported processes that enabled to recover enzyme-unextractable AXs from DWB, including an original and up-scalable hydrothermal extraction. Phytate contents of isolated AXs are described for the first time.BARCELONE (474 SPW 6511

Effect of water uptake on amorphous inulin properties

Physical property changes of amorphous spray-dried inulin were investigated during water uptake at 20 degrees C. Modulated Differential Scanning Calorimetry (MDSC) and Wide Angle X-ray Scattering (WAXS) were used to investigate the evolution of the glass transition temperature (T-g) and the crystallinity index, respectively. The water content, crystallization and thermal properties relationship enabled the identification of three zones in the T-g-water content state diagram. Zone I delimited inulin in a glassy amorphous state, while zone II characterized inulin in a liquid amorphous state. Inulin crystallized and caked when T-g was below the storage temperature of 20 degrees C, but crystallization (zone III) was not spontaneous and was delayed by the defined zone II. The crystallization led to thermograms with an endotherm close to T-g. Temperature-Resolved WAXS allowed to correctly ascertain the MDSC endothermic peak as a melting peak because the crystallinity index was maximal at onset temperature of the transition, and dropped to zero at the endset temperature. (C) 2008 Elsevier Ltd. All rights reserved

Development of gelling properties of inulin by microfluidization

In this paper, we report the impact of a microfluidic device (Microfluidizer (R)) on the development of gelling properties of inulin-water systems. Inulin dispersions at a concentration of 2, 7 and 15%, w/w, were subjected to microfluidization treatments at 30 MPa with various numbers of circulations in the apparatus (1, 2 or 5 passes). The high shear stress treatment did not induce a chemical composition change of inulin. However, it allowed an increase of the gel-like behavior of the system as well as the viscosity of the inulin dispersion, transforming a visual aspect of the product similar to milk, to a system similar to yogurt or margarine depending on the concentration and the number of passes in the Microfluidizer (R). The viscosity increased with both the number of passes and the inulin concentration. Granulometry as well as optical and electronic microscopy ascertained the reduction of the particle size and the formation of a network composed of agglomerates which interacted with the solution and thus led to textural modifications. (C) 2009 Elsevier Ltd. All rights reserved

Evaluation of arabinoxylan oligosaccharides on physicochemical properties of chitosan based films

peer reviewedBARCELONE (474 SPW 6511)

Use of wheat bran arabinoxylans in chitosan-based films : effect on physicochemical properties

The aim of this work was to evaluate physicochemical properties of chitosan-based films with different fractions of arabinoxylans (AXs). Five fractions composed by AXs or mixtures of AXs and arabino-xylo-oligosaccharides (AXOS) obtained through three different processes were added to chitosan-based films. These films were obtained by solvent casting and characterized in terms of water vapor permeability (WVP), opacity, thickness, moisture content and mechanical properties (i.e., tensile strength TS and elongation at break EB), being the chemical interactions evaluated by FTIR. Moisture content values ranged between 20 and 30% for all five studied films being the lowest value observed for chitosan films with the fraction F1 of AX/AXOS (21.1%). The films with incorporation of F3a, F3b and F4 AXs fraction were more opaque (>10%) than the other studied films. Regarding mechanical properties CH films presented EB and TS values of 31.26% and 8.25 MPa, respectively, both these values remain statistically equal with the incorporation of AX/AXOS except for films containing the fraction F1 and F2. For films with the F2 fraction were obtained higher values of EB (41.31%) while for CH films containing the F1 fraction the TS values (13.07 MPa) increased. In conclusion, wheat bran AXs can be successfully incorporated into chitosan-based edible films pro-viding, together with chitosan, an extra functional value to films, due their health benefits.The author Miguel A. Cerqueira is recipient of a fellowship (SFRH/BPD/72753/2010) supported by Fundacao para a Ciencia e Tecnologia, POPH-QREN and FSE (FCT, Portugal). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", REF. NORTE-07-0124-FEDER-000028 Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER. The authors also thank the Walloon Region (Belgium) through BARCELONE project (number SPW 6511)

Characterization of the physical state of spray-dried inulin.

Modulated differential scanning calorimetry, wide angle x-ray scattering, and environmental scanning electron microscopy were used to investigate the physical and morphological properties of chicory root inulin spray dried under different conditions. When the feed temperature increased up to 80 degrees C, the average degree of polymerization of the solubilized fraction increased, leading to a higher glass transition temperature (Tg). Above 80 degrees C, the samples were completely amorphous, and the Tg did not change. The starting material was semicrystalline, and the melting region was composed of a dual endotherm; the first peak subsided as the feed temperature increased up to a temperature of 70 degrees C, whereas above 80 degrees C, no melting peak was observed as the samples were completely amorphous. To a lesser extent, the inlet air temperature of 230 degrees C allowed a higher amorphous content of the samples than at 120-170 degrees C but induced a blow-out of the particles