Eggshell membrane peptides: From preparation and flavor modulation to Nano-delivery systems

Eggshell membrane (ESM), an underused poultry by-product (>90% protein), represents a promising source of antioxidant peptides, yet its valorization remains constrained by poor enzymatic accessibility, hydrolysis-induced off-flavors, and low oral bioavailability. To advance ESM utilization, we propose a set of integrated strategies. (i) Solubilization-enzymatic gradient treatment has been demonstrated to disrupt the dense fibro-porous architecture of ESM, thereby enhancing protease accessibility-a conclusion drawn from existing experimental evidence. (ii) Drawing on insights from flavor modulation of other protein hydrolysates, we envision that synergistic enzyme-microbe systems could offer a balanced strategy for harmonizing hydrolysis efficiency and sensory quality by exploiting the complementary strengths of both components. (iii) Similarly inspired by advances in peptide delivery, we postulate that chemical modifications (e.g., cyclization, PEGylation, fatty acid acylation) may improve peptide stability and membrane permeability, while nano-delivery systems (e.g., liposomes, polymeric nanoparticles, nanoemulsions) could confer protection against gastrointestinal degradation and facilitate intestinal transport. By connecting pretreatment, hydrolysis, flavor modulation, and delivery, an integrated framework is proposed as a forward-looking concept to guide future ESM peptide development toward functional food application.