Effect of wet fractionation conditions and pulsed electric field on arabinoxylan and protein recovery from maize

Abstract

Maize wet fractionation by-products are primarily used as feed but offer potential for food applications. Arabinoxylans (AXs) and proteins are particularly valuable due to their network-forming properties, which depend on their molecular structure. This study assessed the effect of the steeping conditions (acid type and pH variation) combined with a pulsed electric field (PEF) as a strategy for recovering these polymers, while also evaluating their effect on the recovery yield, fraction composition, and key AX characteristics. The physical properties were studied in selected fractions to investigate the process-induced structural changes. Lactic acid and hydrochloric acid (pH 2.5) were most effective in enhancing AX and protein recovery in fiber-rich (FF) and protein-rich (PF) fractions, respectively, while acetic acid exhibited the lowest efficiency. However, bound polyphenols were best retained in the FF when lactic acid was used, indicating the lowest structural damage to AXs, compared to other acids and using a higher pH. Additional PEF pre-treatment significantly enhanced the release of proteins, dietary fiber, and fat from the FF while inducing physical modifications to the fractions (PF: higher protein unfolding, FF: improved water-binding, pasting when using PEF). These findings highlight the potential of optimizing the processing conditions to adjust the recovery of proteins and AXs from maize, while minimally affecting their functionality.