This study investigated the effects of transglutaminase (TGase) content (0%, 0.5%, 1%, 1.5%) and heat treatment (25 °C, 70 °C, 80 °C, 90 °C) on the structure and gel properties of camel casein protein. The results indicate that a TGase concentration of 0.5% combined with a heat treatment of 90 °C in SDS-PAGE facilitates the aggregation and crosslinking of protein molecules to form polymers, with the degree of crosslinking increasing alongside the TGase concentration. In FTIR, the treatment with TGase and heat resulted in a shift of the absorption peak of the amide I band, indicating a transition of the secondary structure from a loose to an ordered configuration. Additionally, surface hydrophobicity and heat enthalpy values were significantly increased, while the thermal transition temperature of casein gradually decreased. Following TGase binding and heat treatment, casein protein molecules formed a network structure characterized by small pore sizes and close crosslinking. Rheological analysis revealed that 0.5% TGase treatment significantly lowered the gel formation point of casein, promoted gelation, and effectively enhanced the mechanical properties and water-holding capacity of the casein gels. These findings provide theoretical reference for the development of camel protein modification and gel products.

Hypertension is a severe global public health issue. Food-derived angiotensin-converting enzyme (ACE)-inhibitory peptides have shown great potential as safe and effective alternatives to synthetic antihypertensive drugs. Camel milk is rich in bioactive peptides. This study aimed to screen for ACE-inhibitory peptides from hydrolyzed camel casein, explore their inhibitory mechanisms and endothelial protective effects in vitro, and reveal their potential antihypertensive pathways using network pharmacology. This study screened three peptides with angiotensin-converting enzyme (ACE) inhibitory activity from enzymatically hydrolyzed camel casein components: MVPFLQPK, VPFLQPKVM, and QKWKFL, with IC₅₀ values of 277.1, 396.9, and 486.9 μmol/L, respectively. Enzyme inhibition kinetics analysis indicated that MVPFLQPK exhibited a non-competitive inhibition pattern, VPFLQPKVM exhibited a mixed inhibition pattern, and QKWKFL exhibited a competitive inhibition pattern. Molecular docking revealed that all three peptides formed hydrogen bond interactions with ACE, and QKWKFL and VPFLQPKVM directly bound to the enzyme’s active site to inhibit substrate catalysis. Molecular dynamics simulation further confirmed the high stability of the three peptide–ACE complexes, with binding free energies from −34.24 to −51.19 kcal/mol. The primary contributing forces include hydrogen bonds, van der Waals interactions, electrostatic forces, and nonpolar solvation effects. Network pharmacology analysis suggested that these peptides may exert synergistic antihypertensive effects by regulating multiple blood pressure-related pathways, including the renin–angiotensin system, renin secretion, and calcium signaling pathways, by acting on key targets such as ACE, REN, SRC, and MMP9. Cell experiments demonstrated that all three peptides exhibited no cytotoxicity in the Ang II-induced HUVEC injury model, significantly promoted NO release, inhibited ET-1 secretion, and possessed endothelial protective potential. This study investigated the in vitro ACE-inhibitory mechanism of peptides derived from camel milk and their potential role in blood pressure regulation, providing experimental evidence for subsequent in vivo activity validation and the development of functional camel milk protein products.

Background: The sensory quality of melon (Cucumis melo L.) is determined by the complex interplay of metabolites within the fruit. However, the underlying metabolic mechanisms based on consumer sensory experience remain underexplored. Methods: Sensory evaluation was conducted on twelve melon cultivars, recording flesh color and quantitatively scoring acidity, sweetness, firmness, and aroma intensity. Based on the sensory results, eight cultivars were selected to establish two contrasting groups: sweet-type vs. acidic-type and orange-fleshed vs. green-fleshed. Untargeted metabolomics (UPLC-QTOF-MS) was then performed to analyze the samples, and differential metabolites were screened using OPLS-DA combined with univariate analysis. Results: Pathway enrichment analysis revealed that the key distinction between sweet and acidic taste profiles was associated with the specific accumulation of citric acid within the tricarboxylic acid (TCA) cycle in the acidic-type group. Regarding flesh color, the orange-fleshed group was enriched with carotenoid derivatives like β-citraurinene and the oxidized tocopherol product α-tocopherolquinone, whereas the green-fleshed group mainly accumulated phytol, a chlorophyll degradation product, along with more abundant terpenoids. Conclusions: By integrating sensory phenotyping with metabolomic analysis, this study identified key differential metabolites and candidate pathways associated with taste and color in melon, providing metabolic insights and data resources for quality evaluation and regulation.