Effects of malting process on molecular weight distribution and content of total and water-extractable arabinoxylan in barley

Abstract

This work aims to evaluate the effects of the malting process on the malt total and water-extractable (WE) arabinoxylan (AX), also considering the barley cultivar and year of cultivation. The WEAX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC) - triple detector array (TDA). Most of the barley malt WEAX showed a molecular weight over 4.0 × 105 Da with a random coil conformation. Compared to raw barley, the malts show analogous content of AX and WEAX, similar intrinsic viscosity, less rigid conformation, and higher polydispersity. The WEAX content of malt was highly and negatively related to the common quality parameters, resulting in a useful indicator of malt modification, even more representative than the total AX content. WEAX is highly positively related to the Congress wort viscosity, and thus, lautering could be more significantly affected by WEAX rather than total AX content.