Optimization and Validation of Arabinoxylan Quantification in Gluten-Free Cereals via HPAEC-PAD Based on Design of Experiments

Arabinoxylans (AXs) are dietary fibers in monocotyledon cell walls that benefit digestive health and enhance food functionality. Despite their importance, no standardized method exists for AX quantification in gluten-free (GF) cereals. This study investigated the effect of hydrolysis parameters for AX quantification in GF cereals (maize, rice, oat) with varying AX content and nutritional profiles to address matrix effects. The effects of trifluoroacetic acid (TFA) concentration (0.25–4 M), temperature (90–127 °C), and time (1–5 h) on hydrolysis efficiency were examined, whereby temperature showed, in contrast to acid concentration and time, a pronounced influence. The design of experiment (DoE) model predicted 2 M TFA, 2.4 h, and 103 °C as the optimal conditions for maximizing AX yield without detectable monosaccharide decomposition for all varieties. This was experimentally confirmed with a deviation of less than 10%. An extensive validation confirmed the method’s accuracy and reliability for this unified method.