Distribution and Structural Variation of Arabinoxylans in Common Wheat Mill Streams

Abstract

In 19 wheat-milling fractions total pentosan content, calculated as 0.88 x (% L-arabinose + % D-xylose), varied between 1.44 and 30.66% on dry matter (dm). It increased with ash content once the latter exceeded 0.6% (dm basis). Water-extractable arabinoxylans were recovered by saturating water extracts to 65% ethanol. Their contents in the milling fractions varied between 0.35 and 1.38%, and above 0.6% ash content also increased with this parameter. Their L-arabinose-to-D-xylose ratios ranged between 0.65 and 0.39, with the lowest values found for the fractions with highest ash content, indicating that the ash-rich tissues contain more arabinoxylans that are less branched. (1)H NMR spectroscopy revealed that the decrease in L-arabinose-to-D-xylose ratio was accompanied by an increase in unsubstituted xylose residues and a decrease in disubstituted xylose residues, while the contents of monosubstituted xyloses were virtually constant.

Water-extractable arabinoxylan content in milling fractions of spring wheats Contenido de arabinoxilano extraíble en agua en fracciones pulverizadas de trigos de primavera

“…The results showed that maximum WEAX content was observed in the shorts of Saher-06 (7.9 g/ kg) and was exhibited lowest in Shafaq-06 (5.1 g/kg). The variations in the WEAX content of shorts of different wheat varieties in the present investigation agreed with the ranges of WEAX content of the following researchers: Delcour, Van Win, and Grobet (1999) and Finnie, Bettge, and Morris (2006).…”

“…AX and WEAX content of whole wheat grain was found to be 5.55-7.51% and 0.39-0.81% with hard wheat cultivars exhibiting higher concentrations than soft wheat (Morris, Bettge, King, Garland-Campbell, & Gill, 2009). The distribution and structural variation of AX and WEAX of 19 milling fractions ranged 1.44-30.66% and 0.3-1.38%, respectively (Delcour, Van Win, & Grobet, 1999). …”

Xylan and xylan derivatives - biopolymers with valuable properties, 1. Naturally occurring xylans structures, isolation procedures and properties

“…Barium hydroxide was reported to be an effective tool in fractional extraction of AX from wheat flour 101) , wheat bran 102) , rye grain 29) , as well as sorghum endosperm 103) . Recently, a pilot scale isolation procedure applying a montmorrilonite clay filtration step was elaborated to prepare protein-free ws-AX from wheat bran 104) .…”

Remodelling of arabinoxylan in wheat (Triticum aestivum) endosperm cell walls during grain filling

“…In addition to vibrational spectroscopy, high resolution nuclear magnetic resonance (NMR) spectroscopy has also been used extensively to investigate the structure of AX in wheat (Hoffmann et al 1991(Hoffmann et al , 1992aGruppen et al 1992;Izydorczyk and Biliaderis 1992;Courtin and Delcour 1998;Delcour et al 1999;Selanere and Andersson 2002). However, these studies have been undertaken on AX extracted from flour and then fractionated using various destructive methods, including enzymatic digestion.…”