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Hydrophilic and hydrophobic modified nanomicelles might be more conducive to passage of the gastrointestinal barrier than walnut peptide (WP). In this study, a novel double modified starch polymer, SB-CST-DCA, was synthesized by grafting sulfabetaine (SB) and deoxycholic acid (DCA) onto corn starch (CST) molecules through etherification and esterification. The modification mechanism was discussed to determine its chemical structure, morphological properties, and thermal stability. Peptide-loaded nanomicelles (SB-CST-DCA-WP) were prepared using WP as the core material. The encapsulation efficiency and peptide loading amount reached 76.90 ± 1.52% and 18.27 ± 0.53%, respectively, with good stability and pH-responsive release behavior observed to effectively control WP release and enhance its antioxidant activity. The composite exhibited safety, non-toxicity, and good blood compatibility at concentrations below 125 μg/mL. Duodenum was identified as the main absorption site with an absorption ratio of 41.16 ± 0.36%., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study aimed to utilize zinc coordination to promote the hypoglycemic and antioxidant properties of walnut-derived peptides, such as walnut protein hydrolysate (WPH) and Leu-Pro-Leu-Leu-Arg (LPLLR, LP5), of which LP5 was previously identified from WPH. The optimal conditions for the chelation were a peptide-to-zinc ratio of 6:1, pH of 9, duration of 50 min, and temperature of 50 °C. The WPH-Zn and LP5-Zn complexes increased the α-glucosidase inhibition, α-amylase inhibition, and antioxidant activity more than WPH and LP5 (p < 0.05). In particular, the antioxidant activity of WPH-Zn was superior to LP5-Zn. This is attributable to the WPH containing more aromatic amino acids, carboxylate groups and the imidazole groups, which implies its capacity to potentially coordinate with Zn 2+ to form the WPH-Zn complex. Moreover, particle size, zeta potential, and scanning electron microscope indicated that the chelation of Zn 2+ by peptides led to intramolecular and intermolecular folding and aggregation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)