This research aimed to investigate the inhibitory mechanism of defatted egg yolk powder hydrolysate (DEYPH) chelated with Mg²⁺ or Ca²⁺ against α-glucosidase (α-Glu). Spectroscopic and enzyme kinetic analyses were combined to elucidate the metal ion binding characteristics and inhibition mode and liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with molecular docking was used to screen and identify key bioactive peptides. DEYPH, obtained by hydrolysis of defatted egg yolk powder (DEYP) with trypsin (2000 U/g) for 2 h, was chelated with Mg²⁺ and Ca²⁺ at a mass ratio of 4:1, pH 7, and 50 ℃, yielding DEYPH-Mg and DEYPH-Ca, respectively. After chelation with Mg²⁺ and Ca²⁺, the inhibition rate of DEYPH against α-Glu significantly increased to 76.05% and 67.05%, respectively. Spectroscopic analysis revealed that Ca²⁺ primarily bound to O and N atoms in DEYPH via non-covalent interactions, while Mg²⁺ interacted with DEYPH through non-covalent interactions and partial coordination bonds, inducing conformational changes that increased the affinity toward α-Glu. The difference in bioactivity between the two chelates was mainly attributed to variations in binding capacity and interaction modes. Enzyme kinetics studies indicated that both DEYPH and its metal chelates inhibitedα-Glu in a non-competitive manner. The key bioactive peptide YVIQEDR was identified through LC-MS/MS coupled with in silico screening. Molecular docking demonstrated that YVIQEDR binds to a non-active site of α-Glu, consistent with the enzyme kinetics results. This study provides a theoretical foundation and technical support for developing peptide-mineral complexes for use as functional food ingredients.

The hypolipidemic effect of egg white hydrolysate (EWH), which was prepared using peptidase 433P, in high-fat diet-fed mice was evaluated using simvastatin and commercially available vinegar-egg hydrolysate as positive controls. The results demonstrated that EWH markedly inhibited body mass gain, regulated dyslipidemia, reduced hepatic lipid abnormalities and inflammatory damage, and inhibited the degeneration and formation of adipocytes and the accumulation of triglycerides in adipose tissue. Afterwards, the effect of gastrointestinal digestion on the blood lipid regulatory activity of EWH was studied. The results showed that the inhibitory effect of EWH on the solubility of cholesterol-rich micelles decreased after gastrointestinal digestion, while the bile acid binding capacity and pancreatic lipase inhibitory activity showed no significant change. At last, three putative pancreatic lipase inhibitory peptides with amino acid sequences of LWVPSVY, YPILPEYLQ and WNIPIGTL were identified by mass spectrometry (MS) and molecular docking. Each of these peptides could interact with the receptor protein 1ETH through hydrogen bonds, electrostatic interactions and hydrophobic interactions, thus exerting hypolipidemic activity.

This paper investigated the changes in the texture, flavor, nutrition, and digestive characteristics of soft-boiled and marinated eggs (SME) during pressurized heat treatment (PHT) at 121 ℃ and 125 kPa for 15, 30, and 45 min. Eggs were pre-cooked in boiling water for 5 min, cooled and peeled in cool water, and then immersed in the brine at 65 ℃ for 2 h to prepare marinated eggs. The results showed that the hardness of SME (121 ℃, 0 min) was the lowest, with the egg white and yolk hardness were 1 368.05 and 530.43 g, respectively. After 15 min of PHT, the hardness of egg white and yolk increased significantly to 2 077.54 and 1 492.75 g (P < 0.05). The relaxation time of non-fluidizable water and free water of egg yolk decreased after PHT. The electronic nose test clearly distinguished the flavor difference before and after PHT, and moderate lipid oxidation was helpful to form new flavors. The protein digestibility of the SME yolk was significantly higher than the PHT groups. Vitamin A content of the SME (0.24 mg/100 g) was 1.26 times higher than the 30 min PHT group. After 30 min heat treatment, the vitamin E content of egg yolk decreased by 7.88%, phosphatidylcholine (PC) and phosphatidylethanolamine (PE) decreased significantly from 2.02 and 1.52 g/100 g to 1.73 and 0.92 g/100 g, respectively. Low temperature group (SME) maintained higher levels of fat-soluble vitamins and lecithin in the egg yolk than PHT groups.

Phosvitin (PV) was treated with high-temperature, mild pressure (HTMP), and enzyme combination, and then phosvitin phosphopeptides-calcium (PPP-Ca) complexes were prepared. The low-calcium specific pathogen free-Kunming (SPF-KM) mice were used to determine the effect of PPP-Ca complexes on intestinal calcium absorption and their utilization for bone formation. The serum calcium content was the highest with the HTMP-Enz-PPP-Ca treatment (2.19 mmol/L), and it significantly down-regulated the abnormal elevation of serum alkaline phosphatase (AKP) caused by calcium deficiency. The low-calcium control group had the lowest calcium deposited to the femur (80.41 mg/g) and the lowest femur bone mineral density (BMD) (0.17 g/cm³), while HTMP-Enz-PPP-Ca significantly improved bone calcium content (94.33 mg/g) and BMD (0.29 g/cm³). The micro-computed tomography (MCT) images showed that the femur with the normal control, PV-Ca, and HTMP-Enz-PPP-Ca treatments had a more compact, complete, and thicker trabecular network than the low-calcium and CaCl₂ treatments. These results indicated that the organic calcium (HTMP-Enz-PPP-Ca) promoted calcium absorption and bone deposition, and the effect of HTMP-Enz-PPP-Ca was better than the inorganic CaCl₂.