Abstract
Novel calcium-chelated peptides have been successfully developed using ultrasound technology from Nannochloropsis oceanica, and they have been found to be superior calcium supplements as natural bioactive peptide calcium chelates. This study has provided a thorough understanding of the interaction between Ca2 + ions and peptides or amino acids, and the optimal conditions have resulted in a calcium chelation rate of 61.89 ± 0.121%, a calcium chelation activity of 9.08 ± 0.151%, and a calcium chelation yield of 65.57 ± 0.190%. The chelates' stability was tested and found to be highly stable at higher pH levels, temperatures, and lower phosphate buffer concentrations (10 mmol/L), with a Ca-peptide retention rate of 81.93 ± 0.00761% after 30 minutes of pepsin digestion. Characterization tests have confirmed the production of new complexes as chelates and different spectral and signal analyses have indicated that metal ions combined with amino, carboxyl, and other active chelating groups in Nannochloropsis peptides form metal chelates. The dense structure of the chelated peptides was depicted through SEM and AFM images. The results of this study have highlighted the potential development of functional foods from Nannochloropsis peptides, which can be used as an alternative to conventional calcium supplements.