Characterization of Wort Arabinoxylans: Molecular Weight, Dispersity, Bound Phenolic Acids, and Polymeric Fraction

This study aimed to examine the molecular characteristics of wort arabinoxylans and the correlation of polymeric arabinoxylans (PAX) with <i>β</i>-glucans and wort viscosity. Twenty-one wort samples were prepared from micro-malted two-rowed spring barley. The average molecular weight of wort arabinoxylans ranged from 1.34 to 2.60 × 10⁵ g/mol (134–260 kDa), with polydispersity indices in the range of 2.61–4.70 indicating broad molecular weight distributions. Two major phenolic acids bound to arabinoxylans, including ferulic and <i>p</i>-coumaric acids, were detected at the concentration of 6.89–10.87 mg/L and 0.43–0.66 mg/L, respectively. These characteristics of wort arabinoxylans were significantly influenced by barley genotype and growing location. PAX with molecular weight ≥30 kDa accounted for 29.38–68.57% of total wort arabinoxylans. PAX (<i>r</i> = 0.54) showed a moderate positive correlation with wort viscosity, less than that of <i>β</i>-glucans (<i>r</i> = 0.72). The correlation between wort PAX and <i>β</i>-glucans was weak (<i>r</i> = 0.20).