pH-Shifting-Assisted Lactic Acid Bacteria Fermentation of Wheat Gluten: An Innovative Strategy to Enhance Solubility, Functionality, and Safety

Wheat gluten (WG) is an abundant but underutilized plant protein, with its application limited by poor solubility and allergenic potential. This study developed an integrated biorefinery approach combining pH-shifting pretreatment (acidic, pH 2→7; alkaline, pH 12→7) with fermentation using Pediococcus acidilactici XZ31 . Alkaline pretreatment proved most effective in dismantling the disulfide-bonded network and inducing a molten globule-like state, significantly enhancing protein solubility and surface hydrophobicity. This structural modification markedly improved substrate accessibility during fermentation, accelerating proteolysis kinetics (peak peptide accumulation at 8 h vs. 20 h in the control). Proteomic analysis revealed more extensive hydrolysis of proline-rich gliadins and glutenins in the alkaline-pretreated group. This hydrolysis yielded a greater diversity of bioactive peptides—including those with drug-delivery, ACE-inhibitory, and antihypertensive properties—and enhanced ACE inhibitory activity. Critically, it also achieved a superior reduction in immunogenic epitopes and IgE-binding activity. This work establishes a scalable, green processing strategy that enhances the functionality and safety of wheat gluten (WG), facilitating its valorization into high-value food ingredients.