Arabinoxylans (AX) are the main component of dietary fibre in durum wheat. Based on their solubility, AX could be classified into water-extractable (WE-AX) and water-unextractable (WU-AX) differing in their physicochemical properties. This difference has significant impact not only on human health but also on wheat processing and end-use quality. For pasta-making quality, WE-AX could be related to a reduction in stickiness whereas WU-AX could help to obtain a better drying. The objectives of this study were: 1 - to determine the genetic variability of TOT-AX and WE-AX contents in Spanish durum wheat cultivars in both whole meal and flour; 2 - to delineate the influence of the genotype and growing environments on these grain components; and 3 - to establish their correlation with other grain quality traits.

In this study, both whole meal and refined flour from thirteen different Spanish durum wheat cultivars grown in five distinct locations from Andalucia were obtained. The amount of WE-AX and TOT-AX were determined through a phloroglucinol colorimetric method, and an analysis of variance (ANOVA) was performed to determine whether genotype, environment or their interaction were significant sources of variation. Also, different wheat grain quality traits were measured: test weight, thousand kernel weight, vitreousness, gluten index, grain protein content; and correlated to TOT-AX and WE-AX content. Arabinoxylan quantification elucidated wide variation for both TOT-AX and WE-AX and significant genotypic effects suggesting that breeding for a higher dietary fibre content in durum wheat is feasible.