Food Chemistry: X最新文献

The quality variation of Goji berry across cultivated zones leaded to an urgent requirement of geographical discrimination. Classical untargeted to targeted strategy faced with the problem of reducing prediction capability. Here, a new untargeted to targeted transition strategy was proposed. At first, the AntDAS-GCMS was used for automatically resolving compounds in untargeted metabolic profiling data to initialize a biomarker set. Compounds with similar chemical structures and/or homologous metabolic pathways were introduced to enhance the coverage of biomarker set, which were used to construct an MRM-based targeted metabolomics method. Quantitative analysis revealed that, proline was dramatically higher in Gansu (252.31 ± 310.68 μg/g) than Ningxia (1.85 ± 4.56 μg/g) and Xinjiang (0.08 ± 0.18 μg/g); cellobiose showed 4.2-fold higher concentration in Xinjiang (84.32 ± 28.54 μg/g) than Ningxia (20.32 ± 3.90 μg/g); glucose was increased in Ningxia (5255.56 ± 425.48 μg/g). The developed strategy achieved >96% prediction accuracy for Goji berries from different zones, outperforming classical untargeted-to-targeted approaches (>91%).

Unique transport conditions in Tibetan regions delay the storage of yak milk, particularly during the July-August peak production period at 18 °C, promoting microbial activity and benzoic acid accumulation. This substantially heightens food safety risks associated with consumption. This study used 16S high-throughput sequencing and non-targeted metabolomics to examine the association between benzoic acid content, dominant bacterial genera, and key metabolites. At 0 h of storage (G0), the dominant genera in yak milk were Kaistella, Lactococcus, and Streptococcus. As storage extended to 12 h (G12) and 24 h (G24), Lactococcus emerged as the dominant genus and the key lactic acid bacterium producing endogenous benzoic acid. Metabolomics identified 729 differentially expressed metabolites. Amino acid metabolism is the primary enriched pathway. Myosmine, L-Methionine, L-Phenylalanine, 3-Isochromanone, and Indoline showed strong correlations with Lactococcus. This study provides a theoretical foundation for improving quality control and safety in yak milk production.

Emulsification was found to enhance the nutritional value and flavor of bovine bone broth, although the specific processing conditions and their impact on amino acid profiles and flavor compounds remained unclear. To address this knowledge gap, this study identified critical parameters for producing clear broth (simmering time of 4 h, temperature of 115 °C, bone size of 4.0 cm, and liquid-to-solid ratio of 1:4) and established optimal conditions for white broth (a shear rate of 5000 r/min, emulsification pressure of 18 kPa, temperature of 50 °C, and duration of 90.0 min). Analysis identified 17 amino acids in both broths, while volatile compound profiling revealed 57 and 64 distinct compounds in the clear and white broths, respectively. The findings provide a theoretical foundation for the high-value utilization of bovine bones.

Tea is mainly produced with spring tea leaves. Summer and autumn tea leaves, characterized by a bitter and astringent taste, are usually discarded. Here, they were turned into osmanthus black tea, and the processing technology was optimized. Optimum process: the ratio of osmanthus to tea was 1:5.3, 16.6 h scenting, two cycles, the highest sensory score was 92.2. E-nose showed significant differences in response values among the W5S, W1W, and W2S sensors. Samples 6, 9, 11, and 12 exhibited high response values across multiple sensors. GC-MS was used to analyze volatile components in osmanthus black tea and the black tea base. A total of 259 volatile components were identified, and 14 key aroma-active compounds were screened, including β-ionone, γ-dodecalactone, γ-decalactone, phenylethanol, and linalool.

The potential role of prickly ash extracts (PAEs) in enhancing garlic-clove shaped protein gel (GSPG)-forming capacity of mandarin fish (Siniperca chuatsi) myofibrillar protein (MP) was studied. PAEs with 0%, 20%, 60%, and 100% ethanol were utilized to systematically analyze changes in the physicochemical properties, water retention, chemical forces, and protein structure of GSPG. Results demonstrated that PAE60 (38.09 mg gallic acid equivalent/g) significantly improved gel strength and water-holding capacity compared to the control (P < 0.05). The immobilized water (23.04% decrease of relaxation time), hydrogen bonds (56.74% increase), disulfide bonds (174.31% increase), and β-sheet (49.42% increase) became significantly better than the control (P < 0.05). The gel microstructure had more orderly and compact networks with relatively increases of fractal dimension (1.83%), porosity (22.32%), and number of pores (23.66%) with statistical significances (P < 0.05). The findings could lay a theoretical groundwork for improving garlic-clove shaped fish protein with plant polyphenols.

Accurately identifying grazing (GZ) and supplementary feeding (SF) patterns in yak milk is important for product authentication; however, current methodologies are often expensive and time consuming. In this study, we examined 523 milk samples of lactating yaks at four stages of SF and tested 21 machine learning algorithms to develop a rapid and cost-effective classification method using routine compositional parameters. Ensemble learning techniques performed better than others, with XGBoost having the best accuracy (92%) and AUC (0.94). Multidimensional interpretability analyses, including SHAP, PDP, and ICE, identified fat content (27.8%) and lactose (23.1%) as the most important discriminators, along with biologically meaningful interactions, such as between fat, lactose, and freezing point. This interpretable framework provides a practical, low-cost method for milk authentication of yaks using ordinary dairy analyzers, providing a methodological foundation for the establishment of standardized GZ certification systems in milk production from yaks.

This study investigated the flavor differences among summer pasture-grazed (SM), winter pasture-grazed (WM) and winter stall-fed (HM) yaks using metabolomics, lipidomics and headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The SM group showed n-3 polyunsaturated fatty acids (n-3 PUFAs) were 225% and 209% higher than those in the WM and HM groups, respectively, with higher thiobarbituric acid reactive substances (TBARS) and antioxidant enzyme activities. These changes promoted the formation of (E)-2-decenal and 1-octen-3-ol, which impart green and floral aromas. Conversely, the HM group's high-energy diet increased monounsaturated fatty acids and essential amino acids (EAAs). This promoted the production of Maillard-derived furfural and maintained the oxidative-antioxidant balance, preserving nutty and tallowy flavors. The WM group exhibited off-flavors due to oxidative imbalance, lower PUFAs content, and benzaldehyde accumulation. Overall, feeding regimes shape yak flavor by modulating fatty acid and amino acid compositions and the oxidative-antioxidant balance. This study provides a scientific basis for precision nutrition strategies to optimize flavor in yaks.