Hongwei Zhang

Conventional ACE-inhibitory peptide production methods suffer from low yield, suboptimal activity, and extensive optimization. This study introduces DeepAngio, a novel model to address these limitations and enable targeted release. DeepAngio demonstrates high performance in screening (98.80% accuracy, 99.63% precision, and 96.44% specificity) and classification (88.24% accuracy, 86.76% precision, and 95.16% specificity) validated through 10-fold cross-validation. Moreover, DeepAngio facilitated the development of a method for directional preparation of tuna meat hydrolysates with notable ACE inhibitory activity (IC₅₀, 31.27 ± 0.72 μg/mL). Three novel potent ACE inhibitory peptides were screened from the hydrolysate: LLRP (IC₅₀, 3.44 ± 0.19 μM), LHWPR (IC₅₀, 17.67 ± 1.53 μM), and RFLR (IC₅₀, 42.52 ± 7.50 μM). The peptides inhibited ACE activity via mixed-competitive (LLRP and RFLR) or competitive (LHWPR) mechanisms, forming stable complexes. Spectroscopic and molecular docking analyses revealed distinct binding modes for each peptide.

This study systematically compared the lipidomes of canine, feline, bovine, and caprine milk. Feline milk contained the highest total lipid content (110.83 mg/mL), significantly exceeding that of canine (81.52 mg/mL), caprine (40.27 mg/mL), and bovine milk (36.25 mg/mL). The phospholipid content in both canine (0.97 mg/mL) and feline milk (0.90 mg/mL) was approximately three times higher than that in bovine and caprine milk (approximately 0.30 mg/mL). Compared to bovine and caprine milk (approximately 30%), canine and feline milk had markedly higher proportions of unsaturated fatty acids (approximately 70%) and were enriched with functional long-chain polyunsaturated fatty acids, including arachidonic acid and docosahexaenoic acid. A distinctive feature was that over 60% of palmitic acid was esterified at the sn−2 position of triacylglycerols in canine and feline milk, a structural similarity shared with human milk. Lipidomic analysis identified 2708 lipid molecules across the four milk types, revealing several triacylglycerol species as potential species-specific biomarkers. These findings provide a concrete scientific basis for developing precisely formulated milk replacers that meet the specific nutritional requirements of puppies and kittens.

The escalating demand for traceability and authentication of aquatic products, driven by significant quality and commercial value differences between wild and farmed fish, necessitates applicable analytical strategies. Sequential window acquisition of all theoretical fragment ion mass spectra (SWATH-MS)-based proteomics, along with multivariate statistical analysis, was employed to discriminate wild and farmed populations of the Four Major Chinese Carps: Mylopharyngodon piceus, Ctenopharyngodon idellus, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis. As a consequence, 24 proteins were identified as discriminators with the model of orthogonal partial least-squares-discriminant analysis (OPLS-DA) and validated by hierarchical clustering analysis (HCA) with visually significant abundance variations between wild and farmed populations. Gene Ontology (GO) annotation additionally revealed that these biomarkers were predominantly involved in energy metabolism and structural development, reflecting molecular adaptations to distinct habitat environments. The applicability of the developed OPLS-DA models to traceability of wild and farmed populations of the Four Major Chinese Carps was also verified by the commercial real-life samples.

Crustacean shellfish are major allergens in East Asia. In the present study, a major allergic protein in crustaceans, tropomyosin, was detected accurately using multiple reaction monitoring mode-based mass spectrometry, with shared signature peptides identified through proteomic analysis. The peptides were deliberately screened through thermal stability and enzymatic digestion efficiency to improve the suitability and accuracy of the developed method. Finally, the proposed method demonstrated a linear range of 0.15 to 30 mg_TM/kg_food (R² > 0.99), with a limit of detection of 0.15 mg_TM/kg _food and a limit of quantification of 0.5mg_TM/kg_food and successfully applied to commercially processed foods, such as potato chips, biscuits, surimi, and hot pot seasonings, which evidenced the applicability of proteomics-based methodology for food allergen analysis.

The consumption of poultry eggs has increased in recent years owing to the abundance of production and improvements in living standards. Thus, the safety requirements of poultry eggs have gradually increased. At present, few reports on analytical methods to determine banned veterinary drugs during egg-laying period in poultry eggs have been published. Therefore, establishing high-throughput and efficient screening methods to monitor banned veterinary drugs during egg-laying period is imperative. In this study, an analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with QuEChERS-based techniques was developed for the simultaneous determination of 31 banned veterinary drugs encompassing nine drug classes (macrolides, antipyretic and analgesic drugs, sulfonamides, antibacterial synergists, anticoccidials, antinematodes, quinolones, tetracyclines, amphenicols) in different types of poultry eggs. The main factors affecting the response, recovery, and sensitivity of the method, such as the extraction solvent, purification adsorbent, LC separation conditions, and MS/MS parameters, were optimized during sample pretreatment and instrumental analysis. The 31 veterinary drug residues in 2.00 g eggs were extracted with 2 mL of 0.1 mol/L ethylene diamine tetraacetic acid disodium solution and 8 mL 3% acetic acid acetonitrile solution, and salted out with 2 g of sodium chloride. After centrifugation, 5 mL of the supernatant was cleaned-up using the QuEChERS method with 100 mg of octadecylsilane-bonded silica gel (C₁₈), 50 mg of N-propylethylenediamine (PSA), and 50 mg of NH₂-based sorbents. After nitrogen blowing and redissolution, the 31 target analytes were separated on a Waters CORTECS UPLC C₁₈ analytical chromatographic column (150 mm×2.1 mm, 1.8 μm) at a flow rate, column temperature, and injection volume of 0.4 mL/min, 30 ℃, and 5 μL, respectively. Among these analytes, 26 analytes were acquired in dynamic multiple reaction monitoring (MRM) mode under positive electrospray ionization (ESI⁺) conditions using (A) 5 mmol/L ammonium acetate (pH 4.5) and (B) acetonitrile as mobile phases. The gradient elution program was as follows: 0-2.0 min, 12%B-30%B; 2.0-7.5 min, 30%B-50%B; 7.5-10.0 min, 50%B; 10.0-10.1 min, 50%B-100%B; 10.1-12.0 min, 100%B; 12.0-12.1 min, 100%B-12%B; The five other target analytes were acquired in MRM mode under negative electrospray ionization (ESI^-) conditions using (A) H₂O and (B) acetonitrile as mobile phases. The gradient elution program was as follows: 0-2.0 min, 12%B-40%B; 2.0-6.0 min, 40%B-80%B; 6.0-6.1 min, 80%B-100%B; 6.1-8.0 min, 100%B; 8.0-8.1 min, 100%B-12%B. Matrix-matched external standard calibration was used for quantification. The results showed that all the compounds had good linear relationships within their respective ranges, with correlation coefficients of >0.99. The limits of detection (LODs) and quantitation (LOQs) were 0.3-3.0 μg/kg and 1.0-10.0 μg/kg, respectively. The average recoveries of the 31 banned veterinary drugs spiked at three levels (LOQ, maximum residue limit (MRL), and 2MRL) in poultry eggs ranged from 61.2% to 105.7%, and the relative standard deviations (RSDs) ranged from 1.8% to 17.6%. The developed method was used to detect and analyze banned veterinary drugs in 30 commercial poultry egg samples, including 20 eggs, 5 duck eggs, and 5 goose eggs. Enrofloxacin was detected in one egg with a content of 12.3 μg/kg. The proposed method is simple, economical, practical, and capable of the simultaneous determination of multiple classes of banned veterinary drugs in poultry eggs.

The aim of this study is to explore differences in the peptidomics of Saccharomyces pastorianus protein hydrolysates treated with different enzymes. Briefly, differences in the peptide fingerprints and active peptides of neutral protease/papain-hydrolyzed S. pastorianus were analyzed using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) combined with PEAKS Online 1.7 analysis software, Peptide Ranker, and the BIOPEP database. Compared to traditional databases, the PEAKS Online uses de novo sequencing for analysis to obtain oligopeptides smaller than pentapeptides. It provides more comprehensive data of the peptide sample. In this study, enzymatic hydrolysates of S. pastorianus protein were prepared under the optimum conditions of neutral protease and papain respectively. In total, 7221 and 7062 polypeptides were identified in the hydrolysates of neutral protease and papain, respectively; among these polypeptides, 980 were common to the two enzymes. The 6241 and 6082 unique peptides found in the hydrolysates of neutral protease and papain, respectively, indicated that the peptide fingerprints of the two hydrolysates are quite different. Peptide Ranker predicted that 3013 (41.73%) and 3095 (43.83%) peptides were potentially bioactive in the hydrolysates of neutral protease and papain, respectively. According to the BIOPEP database, neutral protease and papain contained 295 and 357 active peptides, respectively; these peptides were mainly composed of angiotensin converting enzyme (ACE) inhibitors and dipeptidyl peptidase IV inhibitors and antioxidant peptides. The number of active peptides in the hydrolysate of papain was higher than that in the hydrolysate of neutral protease, but the total ion intensity of active peptides in the former was lower than that in the latter. This study revealed the influence of protease type on the composition of enzymatic hydrolysates from S. pastorianus protein. The above results provide a reference for the development of functional products of S. pastorianus protein peptides and the high-value utilization of yeast resources.

The source and type of collagen are crucial to its application, and both play a decisive role. Collagen was prepared from both tilapia skin and bone and skate skin and cartilage, named as CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c, respectively. Types, distributions, structures, and self-assembly of collagen were studied. It showed that yellow collagen fibers from skin arranged longitudinally, while collagen fibers from skate cartilages displayed varying colors. CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c showed the typical amide A (3316–3336 cm⁻¹) and amide B (2929–2948 cm⁻¹) in FTIR spectra. CI-TI-b and CII-SK-c showed 218–229 nm of UV absorption, 11.56–12.20 Å of d values in XRD, and 0.12–0.14 of Rpn values in CD. The thermal denaturation temperatures of CI-TI-s and CI-SK-s were 30.7 and 20.6 °C, respectively. The self-assembly of CI-TI-s and CII-SK-c were maximum at pH 7.2 and 7.4–7.6, respectively. The unique collagen peptides of tilapia and skate were GPSGPQGAVGATGPK, PAMPVPGPMGPMGPR, SPAMPVPGPMGPMGPR, GESGPSGPAGPAGPAGVR, SSGPPVPGPIGPMGPR, GLTGPIGVPGPPGAQGEK, GLAGPQGPR, and GLSGDPGVQGIK, respectively. The unique peptides of type I and type II collagen were GPTGEIGATGLAGAR, GVLGLTGMR, LGLTGMR, GEPGAAGPAGPSGPMGPR, SSGPPVPGPIGPMGPR, and GLSGDPGVQGIK, respectively.