Yue Wang

This study aimed to systematically compare the functional properties of the four major components (albumin, globulin, prolamin, and glutelin) of protein from Yunnan deep-veined walnuts to screen for protein-based carrier materials with good processing adaptability and the ability to efficiently encapsulate the active ingredient rutin. In addition, the binding and molecular interactions between the preferred protein and rutin were analyzed. The results indicated that albumin exhibited superior performance compared to the other three components in solubility, emulsifying properties, foaming properties, and gel properties, and demonstrated the strongest processing applicability. Further analysis revealed that albumin possessed an excellent amino acid composition (essential amino acid content accounting for 42.30%) and antioxidant activity (with the highest ABTS scavenging rate reaching 85.71 ± 0.26%), which indicated its considerable potential as a functional carrier. Loading rutin onto albumin yielded a walnut albumin–rutin complex (WA@Rut), which significantly enhanced the thermal stability of albumin (with the thermal denaturation temperature elevated to 108.72 °C) and the storage stability of rutin (66.16 ± 5.05% retention after 22 days of storage). Combined analyses of FT-IR spectroscopy, intrinsic fluorescence spectroscopy, molecular docking, and molecular dynamics simulations confirmed that rutin primarily bound to albumin via hydrogen bonding and electrostatic interactions, and formed a stable complex structure. SEM images revealed that the composite surface was smooth and exhibited a flake-like morphology. In conclusion, walnut albumin is a protein resource with significant functional potential in Yunnan deep-veined walnuts, and it exhibits strong processing applicability and enables efficient encapsulation and protection of active ingredients. This study provides novel strategies and theoretical foundations for the high-value utilization of walnut protein.

Diannan small-ear pig (DSP) ham is known for exceptional flavor. However, the composition of flavor components and the mechanisms underlying flavor development remain unclear. In this study, we employed lipidomics, flavoromics, and ultra-high-performance liquid chromatography–tandem mass spectrometry technologies to investigate the composition and formation mechanism of DSP ham flavor compounds. On a 10-point scale, the results demonstrated that DSP ham had good flavor qualities with sensory scores of 8.6 ± 0.52 for flavor, 7.9 ± 0.57 for taste, 8.2 ± 0.79 for texture, 8.8 ± 0.42 for color, and 8.3 ± 0.48 for acceptability. A total of 1534 lipids, 80 volatile flavor compounds, and 25 free amino acids were identified in the ham, including 14 characteristic lipids and 28 characteristic flavor compounds. Triglycerides (TG) and diacylglycerol (DG), two important lipids, are broken down into free fatty acids, which are essential building blocks for flavor formation. Non-volatile sweet amino acid L-alanine and bitter amino acid L-lysine are combined with volatile components, including 1-octene-3-ol, hexanal, benzaldehyde, and octanal, to enhance the development of DSP ham flavor. Correlation analysis indicated that key lipids, including TG, DG, and phosphatidylcholines (PC), facilitate the formation of volatile compounds in DSP ham via the glycerophospholipid metabolic pathway. This study provides a theoretical reference for further research and product development of high-quality DSP ham.

Selenium nanoparticles (SeNPs) have drawn considerable attention to biomedicine, the food industry, and cosmetics due to their strong antioxidant potential and low toxicity. However, their poor stability limits broader applications. A promising strategy to overcome this limitation involves combining SeNPs with polysaccharides. In this study, selenium nanoparticles (MOLP-SeNPs) were synthesized using Moringa oleifera Lam. polysaccharide (MOLP) as a stabilizer and dispersant within a redox system comprising sodium selenite and ascorbic acid. The structural characteristics of the synthesized MOLP-SeNPs were analyzed using spectroscopy. Additionally, their thermal and storage stability was evaluated, and their antioxidant activity was explored through simulated digestion in vitro and a HepG2 cell oxidative stress model. The results demonstrated that well-dispersed, zero-valent MOLP-SeNPs showing a mean particle size of 166.58 nm were synthesized successfully through an MOLP-to-sodium selenite ratio of 2.8:3 at pH 7.3 and 35 °C. The MOLP-SeNPs exhibited excellent stability during preparation. In simulated in vitro digestion and H₂O₂-induced oxidative stress experiments on HepG2 cells, MOLP-SeNPs displayed strong free radical scavenging capacity while improving antioxidant activity. Cellular experiments deeply revealed that pretreatment with MOLP-SeNPs significantly improved cell viability and provided a pronounced protective effect against oxidative damage. In conclusion, MOLP-SeNPs represent a novel antioxidant with promising applications in food and biomedicine.

Finding stable and bioavailable calcium supplements is crucial for addressing calcium deficiency. In this study, glycated peptide–calcium chelates (WMPHs–COS–Ca) were prepared from walnut meal protein hydrolysates (WMPHs) and chitosan oligosaccharides (COSs) through the Maillard reaction, and the structural properties and stability of the WMPHs–COS–Ca were characterized. The results showed that WMPHs and COSs exhibited high binding affinities, with a glycation degree of 64.82%. After glycation, Asp, Lys, and Arg decreased by 2.07%, 0.46%, and 1.06%, respectively, which indicated that these three amino acids are involved in the Maillard reaction. In addition, compared with the WMPHs, the emulsifying ability and emulsion stability of the WMPHs–COS increased by 10.16 mg²/g and 52.73 min, respectively, suggesting that WMPHs–COS have better processing characteristics. After chelation with calcium ions, the calcium chelation rate of peptides with molecular weights less than 1 kDa was the highest (64.88%), and the optimized preparation conditions were 5:1 w/w for WMPH–COS/CaCl₂s, with a temperature of 50 °C, a chelation time of 50 min, and a pH of 7.0. Scanning electron microscopy showed that the “bridging role” of WMPHs-COS changed to a loose structure. UV–vis spectroscopy and Fourier transform infrared spectrometry results indicated that the amino nitrogen atoms, carboxyl oxygen atoms, and carbon oxygen atoms in WMPHs-COS chelated with calcium ions, forming WMPHs-COS-Ca. Moreover, WMPHs-COS-Ca was relatively stable at high temperatures and under acidic and alkaline environmental and digestion conditions in the gastrointestinal tract, indicating that WMPHs–COS–Ca have a greater degree of bioavailability.