Food Chemistry: X最新文献

This study developed an antibacterial pad by immobilizing lysozyme (LZ) within porous cellulose through polyvinyl alcohol (PVA) cross-linking, reinforced with polylactic acid (PLA) barrier layers. The PLA-PVA/LZ pad demonstrated significantly enhanced structural properties, including a 65.52% increase in TS, a 78.88% rise in WCA, and an 87.62% reduction in water absorption. At an optimal loading of 4% LZ, the pads exhibited potent antibacterial efficacy, inhibiting Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) growth by 93.93% and 86.73%, respectively. Mechanistic investigations revealed that the pad disrupted bacterial cell morphology, compromised membrane integrity, suppressed ATPase activity, and elevated AKP levels. When applied to cooked rice stored at 25 °C, the pad effectively maintained microbial counts below the detection limit for 48 h, extending shelf life by at least 12 h according to Chinese national standards.

α-Tocopherol and γ-oryzanol affect physicochemical properties of oils, while their role in frying oil uptake remains unclear. Thus, the influence of various concentrations of 0-1000 mg α-tocopherol/kg oil and 0-15,000 mg γ-oryzanol/kg oil on the oil absorption of French fries and possible mechanisms were investigated. The results demonstrated that α-tocopherol and γ-oryzanol reduced surface oil by 29.83% and surface-penetrated oil by 28.19% in the fries, compared with control sample. Furthermore, α-tocopherol and γ-oryzanol inhibited the formation of total polar materials and diglycerides, delayed the increase in oil viscosity, and influenced the porosity of French fries. Additionally, α-tocopherol and γ-oryzanol decreased the rate constants for water loss and oil absorption at the French fry-oil interface. The most significant reduction in total oil content was observed with 1000 mg α-tocopherol/kg oil and 10,000 mg γ-oryzanol/kg oil. This study provides new insights for developing low-oil fried foods.

Frozen pears undergo complex internal quality changes during frozen storage, while conventional evaluation methods are destructive and time-consuming, limiting rapid or continuous monitoring. This study employed hyperspectral reflectance imaging combined with spectral preprocessing, feature wavelength selection, and machine learning algorithms to model key quality indicators of frozen pears, including soluble solids content (SSC), titratable acidity (TA), and total sugar content (TSC). The results revealed distinct optimal modeling strategies for different quality attributes. Stable predictions of TSC were achieved using full-spectrum data or weak wavelength screening, whereas SSC and TA required targeted wavelength optimization to improve prediction robustness. The optimal models exhibited high coefficients of determination, low prediction errors, and acceptable RPD values across prediction sets. Further validation using the guidance method confirmed stable error distributions without evident overfitting. Overall, this study demonstrates that hyperspectral imaging can provide a reliable alternative for non-destructive quality assessment of Lanzhou frozen pears.

This study aims to investigate how endogenous walnut pellicle polyphenols (WPP) alter the structural and functional properties of walnut protein isolate (WalPI). WPP influence was assessed by adjusting polyphenol content in walnut meal (WM) through treatments that peeled and dephenolized the pellicle. Results showed that WPP decreased the β-sheet content of unpeeled walnut protein isolate (UWalPI), increased random coil structures, and induced structural unfolding. These structural changes raised the water-holding capacity of UWalPI from 1.72 to 2.48 g/g and enhanced foaming capacity and foam stability by 31.12% and 46.44%, respectively. Conversely, surface hydrophobicity declined by 62.9%, oil-holding capacity reduced to 2.44 g/g, and emulsifying capacity, solubility, and thermal stability were compromised. Scanning electron microscopy indicated WPP-induced rearrangement and aggregation, molecular docking simulations predicted interactions between WPP and WalPI. The results clarify the mechanisms of WPP-WalPI interactions and provide strategies for the application of WM and WalPI in food processing.

Four famous freshwater fish in China are renowned for their high production among freshwater species and are much-prized as sought-after delicacies. However, the distinct taste profiles and the specific associated taste substance of these carps remain poorly understood. This study primarily investigated the taste profiles and associated taste compounds, along with non- volatile metabolites of these four species using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) combined with electronic tongue technology. Results revealed that Mylopharyngodon piceus (MP) exhibited significantly higher levels of total free amino acids and adenosine triphosphate (ATP) compared to the other three fish species (p < 0.05), with contents reaching approximately 388.90 mg/100 g and 140.88 mg/100 g, respectively. Ctenopharyngodon idella (CI) and MP possessed richer tastes compared to Aristichthys nobilis (AN) and Hypophthalmichthys molitrix (HM) based on the electronic tongue analysis. Furthermore, UPLC-MS metabolomics analysis identified 49 key metabolites, highlighting major metabolic pathways including lipid, amino acid, and organic acid metabolism. The findings suggested that variations in taste-related compounds and metabolites within metabolic pathways contribute to the distinct flavor profiles observed among the four famous fish species. This research offers essential insights for aquaculture professionals and researchers focused on enhancing the flavor quality of these key fish species, especially in understanding the regulatory mechanisms involved in flavor development.

Aroma profiles of tomato flesh from 16 tomato varieties with 4 different fruit colors were characterized by headspace-solid phase microextraction coupled with gas chromatography-triple quadrupole mass spectrometry (HS-SPME-GC-MS/MS) and electronic nose (E-nose). A total of 154 volatile organic compounds (VOCs) were qualitatively and semi-quantitatively identified, including 29 aldehydes, 22 hydrocarbons, 21 alcohols, 32 unknown compounds, and others, with aldehydes being the most abundant. Twenty-six characteristic VOCs might be major contributors to tomato flavor by relative odor activity value analysis. The correlation between E-nose sensor responses and GC-MS/MS volatile profiles was also examined. The machine learning models were constructed to show potential for distinguishing the fruit colors of the tomato. Finally, 16 fruit color-indicating VOCs were selected via multivariate data analysis. The present study will contribute to flavor evaluation and provide a chemical basis for future tomato flavor improvement, to be accompanied by sensory validation.

Fermented cowpeas, a traditional Chinese pickle, are valued for their characteristic taste and nutrition. This study examined flavor evolution and microbial dynamics during fermentation and storage via physicochemical analysis, volatile and nonvolatile compounds profiling, and microbial community assessment. 21 and 18 key discriminatory volatiles (VIP > 1) were identified via GC-MS and GC-IMS in cowpea samples, respectively. Multivariate analysis indicated that changes in flavor quality resulted from the combined effects of lactic acid, umami, and sweet amino acids, and 12 key aroma-active compounds (VIP > 1 and OAV > 1). Five core functional microorganisms (Debaryomyces, Companilactobacillus, Levilactobacillus, Chromohalobacter, and Microbacterium) were identified. Pearson correlation analysis revealed positive associations among these microorganisms and lactic acid, amino acids (Glu, Asp, Ala), and several key aroma-active compounds but negative associations with spermidine, tartaric acid, and Asn. These findings link microbial metabolism to flavor development in fermented cowpeas, revealing insights into fermentation-driven flavor modulation.

Walnut pellicle is rich in polyphenols that enhance antioxidant capacity and health benefits, including anti-inflammatory and neuroprotective effects. Profiling these compounds has been hindered by their structural diversity, regional variability, and the limitations of traditional metabolomics approaches. This study employed a pseudotargeted metabolomics strategy, integrating ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) for untargeted profiling and multiple reaction monitoring (MRM) on a QTRAP system for semi-quantification. We analyzed 21 walnut pellicle samples from Xinjiang, Yunnan and the Taihang Mountains, identifying 406 polyphenols, including flavonoids, hydrolysable tannins, phenolic acids, coumarins, lignans and minor constituents. Multivariate analyses (PCA, PLS-DA, OPLS-DA) revealed region-specific metabolic fingerprints. KEGG pathway enrichment highlighted significant variations in flavonoid and phenylpropanoid biosynthesis across regions, with origin-specific markers like casuarinin, prunin, and ε-viniferin supporting provenance authentication. This research bridges the methodological gap in walnut polyphenol analysis and informs quality assurance, targeted breeding, and functional product development in sustainable food systems.

Pumpkin (Cucurbita moschata and Cucurbita maxima) is a nutrient-rich vegetable, yet cooking-induced changes in comprehensive quality attributes across cultivars remain poorly understood. Here, the effects of steaming, boiling, and baking on taste components, texture, nutritional quality, and volatile profiles were systematically evaluated in three pumpkin cultivars. Sugar and starch contents were largely unaffected by cooking, whereas textural properties were significantly altered, with baking causing the least structural disruption. Steaming and boiling increased organic acid and vitamin C contents as well as antioxidant activity. Boiling enhanced carotenoid extractability, with Tian Mi highest at 3.13 mg/g DW. Cultivar-dependent differences were observed: Dan Hong showed higher hardness, chewiness, and gumminess, while Zhen Mi exhibited greater total volatile content. Volatile analysis revealed that cooking, particularly boiling, reduced green and earthy odorants while increasing key aroma-active compounds, including furfural and 4-vinylguaiacol. Overall, boiling provided the most favorable balance between nutritional enhancement and aroma improvement.

To overcome the subjectivity of traditional bacon authentication, this study developed an objective discrimination framework integrating LC-MS/MS-based metabolomics with machine learning. Metabolomic profiling of bacon samples from pork belly (LRW) and pork rump (LRT) identified 100 differential metabolites common to both groups. The Kruskal-Wallis H test (p < 0.05) identified 75 significant features, which were further reduced to 22 key metabolites through random forest-based feature selection and low-variance filtering. Subsequently, a multidimensional evaluation of these 22 key metabolites (VIF < 75, label correlation >85%, and information gain = 1) highlighted four candidate discriminatory metabolites, including 6-hydroxyoctanoylcarnitine characterizing LRT, and dimethylethanolamine, xanthine, and ethyl hydrogen fumarate associated with LRW. Bidirectional validation using RF, KNN, SVM, and FNN models demonstrated robust discriminatory performance. This framework provides a basis for optimizing bacon production and offers a generalizable paradigm for data-driven biomarker discovery in meat products.