Nanoliposomes for encapsulation and calcium delivery of egg white peptide-calcium complex

Oxidation-resistant nanoliposomes loaded with osteogenic peptides: Characteristics, stability and bioaccessibility

Phosphatidylcholine (PC) oxidation leads to the fusion of nanoliposomes and leakage of containment compounds during the storage period. This study aims to improve the oxidation resistance by partially substituting PC in the osteogenic peptides (OPs) loaded nanoliposomes with hydrogenated phosphatidylcholine (HPC). The investigation assessed the characteristics, stability, and bioaccessibility of these novel nanoliposomes. By altering the PC/HPC mass ratio from 1:0 to 0:1, an increase in the encapsulation efficiency (EE), loading capacity (LC), polydispersity index (PDI), and bioaccessibility of OPs-loaded nanoliposomes was observed. Additionally, there was a decrease in thiobarbituric acid reactive substances (TBARS), peroxide value (POV), non-volatile aldehyde, and ketone. The stability of salt decreased when using HPC alone (0:1). The performance of OPs-loaded nanoliposomes with a PC/HPC mass ratio of 1:3 was found to be satisfactory in terms of storage and pH stability. Fluorescence spectroscopy, Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared spectroscopy (FTIR) revealed a tighter lipid aggregation, enhanced intermolecular van der Waals forces, and hydrogen bond formation in membranes of nanoliposomes containing HPC. The addition of HPC to the nanoliposomes delayed the release of peptides in simulated without affecting osteogenic activity. These results provide guidance for the development of oxidation-resistant nanoliposomes loaded with OPs products.

The Formation, Structural Characteristics, Absorption Pathways and Bioavailability of Calcium–Peptide Chelates

Calcium is one of the most important mineral elements in the human body and is closely related to the maintenance of human health. To prevent calcium deficiency, various calcium supplements have been developed, but their application tends to be limited by low calcium content and highly irritating effects on the stomach, among other side effects. Recently, calcium–peptide chelates, which have excellent stability and are easily absorbed, have received attention as an alternative emerging calcium supplement. Calcium-binding peptides (CaBP) are usually obtained via the hydrolysis of animal or plant proteins, and calcium-binding capacity (CaBC) can be further improved through chromatographic purification techniques. In calcium ions, the phosphate group, carboxylic group and nitrogen atom in the peptide are the main binding sites, and the four modes of combination are the unidentate mode, bidentate mode, bridging mode and α mode. The stability and safety of calcium–peptide chelates are discussed in this paper, the intestinal absorption pathways of calcium elements and peptides are described, and the bioavailability of calcium–peptide chelates, both in vitro and in vivo, is also introduced. This review of the research status of calcium–peptide chelates aims to provide a reasonable theoretical basis for their application as calcium supplementation products.

A comprehensive review of calcium and ferrous ions chelating peptides: Preparation, structure and transport pathways

Calcium and iron play crucial roles in human health, deficiencies of which have globally generated public health risks. The poor solubility, low bioavailability and gastrointestinal irritation of existing commercial mineral supplements limit their further application. As an emerging type of mineral supplement, mineral chelating peptides have drawn plenty of attention due to their advantages in stability, absorptivity and safety. A majority of calcium and ferrous ions chelating peptides have been isolated from food processing by-products. Enzymatic hydrolysis combined with affinity chromatography, gel filtration and other efficient separation techniques is the predominant method to obtain peptides with high calcium and ferrous affinity. Peptides with small molecular weight are more likely to chelate metals, and carboxyl, amino groups and nitrogen, oxygen, sulfur atoms in the side chain, which can provide lone-pair electrons to combine with metallic ions. Unidentate, bidentate, tridentate, bridging and α mode are regarded as common chelating modes. Moreover, the stability of peptide-mineral complexes in the gastrointestinal tract and possible transport pathways were summarized. This review is to present an overview of the latest research progress, existing problems and research prospects in the field of peptide-mineral complexes and to provide a more comprehensive theoretical basis for their exploitation in food industry.

Elucidating the Calcium-Binding Site, Absorption Activities, and Thermal Stability of Egg White Peptide-Calcium Chelate

With the current study, we aimed to determine the characteristics and calcium absorption capacity of egg white peptide-calcium complex (EWP-Ca) and determine the effect of sterilization on EWP-Ca to study the possibility of EWP-Ca as a new potential calcium supplement. The results of SEM and EDS showed a high calcium chelating ability between EWP and calcium, and the structure of EWP-Ca was clustered spherical particles due its combination with calcium. The FTIR and Raman spectrum results showed that EWP could chelate with calcium by carboxyl, phosphate, and amino groups, and peptide bonds may also participate in peptide-calcium binding. Moreover, the calcium absorption of EWP-Ca measured by the intestinal everted sac model in rats was 32.38 ± 6.83 μg/mL, significantly higher than the sample with CaCl2, and the mixture of EWP and Ca (p < 0.05) revealed appropriate calcium absorption capacity. The fluorescence spectra and CD spectra showed that sterilization caused a decrease in the content of α-helix and β-sheet and a significant increase in β-turn (p < 0.05). Sterilization changed the EWP-Ca structure and decreased its stability; the calcium-binding capacity of EWP-Ca after sterilization was decreased to 41.19% (p < 0.05). Overall, these findings showed that EWP could bind with calcium, form a peptide-calcium chelate, and serve as novel carriers for calcium supplements.