Chemical and rheological characterization of arabinoxylan isolates from rye bran

Abstract

Background: Rye arabinoxylans (AXs) might be used as baking improvers for gluten-free (GF) bread. However, their extraction process still needs to be improved. Objective and methods:The aim of this study was to simplify AX extraction of rye bran by varying temperature and pH and evaluate its chemical and rheological properties for application in GF bread. Results and conclusion:The results demonstrated that higher amounts of AX and impurities were extracted with the increasing pH and temperature. AX yield reached values up to 3.3 g AX/100 g bran. Highest ferulic acid (FA) content (117.27 ± 1.46 mg/100 g) was achieved at the mildest extraction conditions (30 °C and 0.17 M NaOH). A/X ratio of isolates ranged between 0.53 and 0.57 and the gluten content between 81.30 and 216.78 ppm. Rheological measurements revealed typical pseudoplastic behavior of isolates. AX extracted at 30 °C and 0.17 M NaOH showed a slightly higher initial viscosity in comparison with the other isolates but was still inferior to carboxylmethylcellulose (CMC) and hydroxypropyl methylcellulose (HPMC).

Effect of Differently Extracted Arabinoxylan on Gluten-Free Sourdough-Bread Properties

“…2 Yield is expressed as g AX/100 g rye bran. 3 WEAX, NEAX, and CEAX extractions as reported by Bender et al [3,9].…”

“…Previous research has already confirmed that extraction parameters (solvents, pH, or temperature) significantly modify the chemical and functional properties of AXs, which in turn affect the rheological behavior of gluten-free batters [8,9]. eir effect will closely depend not only on the type and concentration of AX added but also on the selection of GF flour and the presence of oxidants in the batter [3].…”

A sikérfehérjéket nem tartalmazó (gluténmentes) termékek táplálkozási és technológiai minõségének fejlesztése

“…Az õrlemények szénhidrátösszetételének módosításához a partner intézményünk (Universitiy of Natural Resources and Life Sciences, BOKU, Bécs, Ausztria) által elõállított és közös munkával részletesen jellemzett arabinoxilán extraktumot használtunk. 16,17 Az enzimes kezelést a szintén a BOKU kutatói által izolált piranóz-oxidáz enzimmel (44 U/ml) végeztük, az enzimadagolás mennyiségét (20 µl) elõzetes kísérletekben optimáltuk. 18 13…”

Optimization of Arabinoxylan Isolation from Rye Bran by Adapting Extraction Solvent and Use of Enzymes

“…Results showed that an increase in pH and temperature led to higher extraction yields of up to 2.5 g AX/100 g rye bran. Comparatively, Bender and others () simplified the previous extraction process by adapting a broader temperature range (up to 70 °C) with different NaOH concentrations and could therefore promote a higher yield of 3.3 g AX/ 100 g bran. The study demonstrated that harsher extraction conditions contributed to the breakdown of bound FA, which partly decreased the isolate´s crosslinking ability.…”

“…Based on previous studies (Bender and others ; Mansberger and others ), the aim of this study was to further improve and optimize the arabinoxylan isolation procedure in order to obtain on the one hand sufficient yield but on the other hand also improve functional properties of the isolates. To pursue this aim different extraction solvents were investigated: water, sodium carbonate and calcium hydroxide; additionally xylanases were applied to release remaining bound arabinoxylans, which should result in an overall increased yield.…”