Maillard reaction-based conjugation of pea protein and prebiotic (polydextrose): optimization, characterization, and functional properties enhancement

There is a growing demand for plant-based protein ingredients with improved functionality for use in diverse food and nutraceutical applications. In line with this, the current study aimed to investigate the effect of plant protein-prebiotic (polydextrose) conjugation on the techno-functional properties (emulsification, solubility, fat absorption and foaming) of pea proteins through wet heating Maillard reaction. Pea protein (PeP) was conjugated with polydextrose by incubating the mixture at various process conditions (pea protein: polydextrose mass ratios, temperature, and time). Response surface methodology coupled with Box–Behnken design was used to optimize multiple responses, including conjugation efficiency (CE), emulsifying activity (EAI), and foaming capacity (FC). The pea protein conjugate (optimized value) showed improved solubility throughout a wide pH (2–10) range and higher emulsification activity than pea protein alone. The development of conjugates (PeC) was validated through ultraviolet–visible spectroscopy, FTIR, and o-Phthaldialdehyde (OPA) assay. Browning index, FT-IR spectra, thermal properties, and scanning electron microscopy (SEM) micrographs were analyzed for the conjugate (PeC) obtained at optimized values. The FTIR spectra of the conjugates showed new peaks at 3100–3480 cm⁻¹ and 1,000–1,166 cm⁻¹ indicating conjugation. The Maillard conjugation increased the proportion of β-turn, random coil, accompanied by a decrease in α-helix, and β-sheet. These conformational changes were associated to the improved techno-functional properties of the pea protein upon conjugation, offering potential applications in the formulation of plant-based foods and beverages.