Characterisation of enzymatically-induced arabinoxylan-protein interactions in gluten-free model batter

The absence of a viscoelastic gluten network remains a major factor limiting the quality of gluten-free (GF) bakery products. This study examined whether arabinoxylans (AX) from maize (alkaline-extracted, M-CEAX; xylanase-extracted, M-XEAX) and wheat (wheat-extracted AX, WEAX), in combination with maize gluten meal (MGM), can form a cohesive joint polymeric network resembling gluten. Cross-linking was enzymatically induced using laccase or glucose oxidase (GOX) with horseradish peroxidase (HRP). Model batters were assessed through rheological tests (amplitude, frequency, time sweep) and physicochemical methods (particle and molecular size, polymer solubility and bound phenolic/ferulic acid) to evaluate AX-protein interactions. Rheological analyses revealed that laccase increased elasticity in M-CEAX systems but failed to promote strong AX-protein interactions. In contrast, GOX-HRP significantly enhanced the storage modulus (G') in M-CEAX-MGM added model batters, suggesting stronger cross-linking. Particle size results supported this, showing larger d-values and higher span, especially in enzymatically treated M-CEAX formulations. AX solubility increased with M-CEAX alone but remained unchanged with protein addition. Bound phenolic content was higher in laccase-treated than in GOX-HRP-treated systems, indicating weaker cross-linking. Size exclusion chromatography (SEC) showed increased molecular weight in M-CEAX and MGM model batters treated with GOX-HRP, whereas M-CEAX-MGM combinations showed no clear size shift, which can be attributed to large insoluble aggregates not detected by the method. Overall, these findings highlighted the importance of polymer structure and enzyme specificity in modulating network formation. The results suggested that AX-protein interactions can enhance GF batter viscoelasticity and stability, offering a promising strategy to improve the structure of GF bakery products. • Arabinoxylan-protein interactions improve viscoelasticity of gluten-free batters • Glucose oxidase and horseradish peroxidase strengthen polymer crosslinking in batters • Laccase increases batter elasticity but produces weaker AX-protein interactions • Particle size and molecular weight analyses confirm enzyme-dependent network formation