Potential of calcium-chelating bamboo shoot peptides as a novel calcium supplement: preparation, structural characterization, physical properties, and bioactivities

The use of plant protein sources to prepare peptide-chelated calcium is promising for the development of new calcium supplements with enhanced stability and bioavailability. In this study, calcium-chelating peptides were fabricated using hydrolyzed bamboo shoot protein (BSH–Ca 2+ ), the process was optimized, and a comprehensive multi-technique characterization was employed to confirm the structure and bioactivity. The highest chelating ability (54.73 %) and calcium concentration (269.08 mg/g) of BSH–Ca 2+ were achieved using BSH-III, with a peptide-to-calcium ratio of 11:1 and a reaction time of 2 h at pH 7.0 and 50 °C. The addition of calcium changed the surface morphology, crystalline structure, and secondary structure of BSH-Ⅲ, allowing it to transition from a disordered to an ordered structure. BSH-III–Ca 2+ was determined to have a high degree of stability under neutral pH and low-concentration phosphate buffer conditions and was also stable against digestive enzymes. Binding site analysis indicated that calcium ions primarily bind to glutamic acid, aspartic acid, lysine, and cysteine. Calcium binding also enhanced the free radical scavenging activity of BSH-III–Ca 2+ , which is a positive outcome of the development of BSH-III–Ca 2+ as a multifunctional food ingredient. Structural characterization and functional evaluation confirmed the successful preparation and optimization of BSH–Ca 2+ , supporting its potential as a promising nutraceutical ingredient for functional food applications. However, future in vivo research is needed before scaling-up. • Calcium-chelate peptides (BSH-Ca) were successfully prepared from bamboo shoot peptides. • The impact of calcium ions on the structure of BSH was systematically explored. • The binding of calcium ions improved the stability and antioxidant activity of BSH. • The potential binding sites and binding modes of calcium ions were predicted.