Cunfang Wang

A high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of 18 amino acids in special formula milk powder. This method was based on pre-column derivatization with phenyl isothiocyanate, separation on a C18 column, ultraviolet detection, and quantification using external standards. Acid hydrolysis using 6 mol/L HCl under autoclaving at 120 °C for 2 h was optimized and compared with conventional oven hydrolysis at 110 °C for 24 h. The results revealed that all 18 amino acids yielded linear correlation coefficients exceeding 0.999. The limits of detection and quantification ranged from 0.07 to 0.32 μg/mL and from 0.23 to 1.07 μg/mL, respectively. The precision, repeatability, and stability were 0.06%–2.44%, 0.32%–2.22%, and 0.19%–2.77%, respectively, and the spiked recoveries ranged between 85.92% and 107.55%. The developed method allowed the analytical run time for all amino acids to be reduced to 35 min. Another advantage was that the proposed method enabled quantification of tryptophan, asparagine, and glutamine, which are not detected by the standard method defined in GB 5009.124–2016 National food safety standards–determination of amino acids in food. Overall, the obtained results demonstrate that our method allowed the simultaneous quantification of 18 amino acids in special formula milk powder with improved precision, sensitivity, and efficiency after optimization of the hydrolysis and detection conditions. This method is expected to prove suitable for the quality control of foods for special medical purposes.

In this study, we systematically compared the digestion characteristics of cow, goat and donkey β-casein (β-CN) and the differences in their peptide profiles by simulating an infant digestion model in vitro. The results showed that the hydrolysis degree of goat and donkey β-CN was significantly higher than that of cow β-CN (P < 0.05), and their superiority in digestive efficiency was closely related to the large variation in particle size and high surface charge density. Secondary structure analysis showed that the proportion of disordered structures of the 3 β-caseins increased during the digestion process, and the digestion resulted in different degrees of surface hydrophobicity and fluorescence reduction, as well as interfacial activity attenuation of the 3 β-caseins. Peptide profiling further revealed that goat and donkey β-CN digestion products were dominated by < 2000 Da small-molecule peptides (>91%), the proportion of short peptides (5-10 amino acids) was significantly higher than that of cow β-CN (P < 0.05), and the donkey β-CN specifically generated the high-abundance antioxidant peptide VAPFPQPVVPYPQR (28.13%). Sequence homology comparisons indicated that donkey β-CN is more heterologous than cow and goat β-casein, resulting in a unique peptide generation pattern. The present study elucidates the differentiation of the 3 milk-derived β-CNs in terms of digestive kinetics, structural evolution and release of bioactive peptides to provide a scientific basis for infant formula selection.

This study aimed to elucidate the dynamic changes in meat quality attributes and metabolomic profiles of Dezhou donkey longissimus lumborum (LL) during extended chilled storage. Donkey longissimus lumborum (LL) muscles (n = 4) were vacuum-packaged 24 h post mortem and stored at 0–4 °C for 0, 7, 14, or 21 days, followed by a 5-day aerobic display. Meat quality parameters and microstructural characteristics were evaluated, and untargeted metabolomics was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Extended storage significantly improved tenderness (shear force decreased from 76.40 to 27.84 N; p < 0.05), concurrent with progressive muscle fiber degradation. However, color stability deteriorated markedly, with accelerated declines in redness observed beyond 14 days. Metabolomics analysis demonstrated that storage resulted in a substantial accumulation of lysophospholipids, free amino acids, and nucleotide degradation products, indicative of membrane deterioration, proteolysis, and ATP catabolism. Notably, acetyl-L-carnitine, cysteinylglycine (Cys-Gly), and nicotinamide exhibited progressive depletion, correlating with diminished antioxidant capacity and color deterioration. KEGG pathway enrichment revealed significant alterations in glycerophospholipid, amino acid, and glutathione metabolism. This study provides the first comprehensive metabolomic characterization of donkey meat during chilled storage, identifying potential biomarkers for freshness assessment and offering a scientific foundation for developing targeted preservation interventions.

Functional dairy products represent a substantial area of interest, but the market offers a limited variety of products enriched with oligopeptides. This study focused on the incorporation of high Fischer ratio oligopeptide (HFO) derived from whey protein into goat milk using ultrasonic-assisted pasteurization. A comprehensive examination was conducted to assess the impact of the oligopeptide on the physicochemical properties, stability, and functional characteristics of goat milk. This analysis encompassed the evaluation of protein composition and content, antioxidant capacity, and various other functional attributes. The results revealed that HFO addition significantly increased both protein and whey protein content, enhancing nutritional value. Moreover, HFO fortification notably improved antioxidant activity, foamability, and emulsification properties. Although HFO incorporation elevated viscosity and particle size and reduced the absolute zeta potential, it minimally affected the distribution of fat globules. Storage stability studies indicated that HFO supplementation contributed to extending the shelf life of pasteurized milk. This study demonstrates the dual functionality of HFO in enhancing the nutritional profile and improving the techno-functional properties of goat milk. These findings offer valuable insights for advancing the production of functional goat milk products using oligopeptides as bioactive ingredients or specialized foods for medical purposes.

Ulcerative colitis (UC), a chronic inflammatory bowel disease (IBD), presents therapeutic challenges due to the limitations and side effects of current treatments, creating a need for safer and more effective alternatives. Despite several studies on the health benefits of donkey milk, its specific impact on UC remains unsolved. This study investigates the therapeutic potential of donkey whey protein (DWP), a bioactive-rich functional food, in alleviating UC symptoms in a mouse model of dextran sodium sulfate-induced colitis. The DWP was processed using thermal and nonthermal techniques, including high-temperature, long-time (HTLT) pasteurization, ultrasonic processing (300 W), and UV irradiation, to evaluate the impact of processing methods on its therapeutic efficacy. The results demonstrated that when processed nonthermally, DWP mitigated colitis symptoms such as weight loss, diarrhea, and colon shortening. Histological analysis revealed improved mucosal integrity and reduced inflammation in the colon, with nonthermal treatments showing superior effects. The DWP treatment enhanced antioxidant activity, suppressed proinflammatory cytokines (TNF-α, IL-6, IL-1β), and modulated the gut microbiota, promoting microbial diversity and restoring microbial balance. Nonthermal treatments were particularly effective in preserving the bioactivity of DWP, highlighting their potential in enhancing the functional properties of whey proteins. These findings suggest that DWP, particularly when processed through nonthermal methods, holds potential as a natural and effective alternative for managing UC and other chronic inflammatory diseases.

Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peer-reviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, dairy, and edible insect/worm products. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.