Foods

Preventing spoilage in food products, particularly in those highly susceptible to rapid deterioration like mutton, has been a persistent challenge in the food industry. In this study, an Active Biological Film (ABF) was developed using chitosan (CS) and whey protein isolate (WPI), with the addition of 0.01 wt% titanium dioxide (TiO₂) and 0.1 wt% white pepper essential oil (WPEO). This ABF was applied to preserve fresh mutton at super-chilling temperatures of −1.7 ± 0.2 °C. The effects of ABF on myofibrillar protein (MP) oxidation and structural characteristics, as well as on the microbial status, physicochemical properties, and sensory quality of mutton, were systematically evaluated. The results demonstrated that, compared to the control group (CK), ABF treatment significantly enhanced the total sulfhydryl content, protein solubility, and zeta potential of MPs, while reducing carbonyl content, surface hydrophobicity, and particle size. MPs in the ABF group showed a higher α-helix proportion and a lower random coil content, along with a notable increase in intrinsic fluorescence intensity. Scanning electron microscopy (SEM) revealed a denser gel structure. Additionally, ABF effectively inhibited microbial growth in mutton, delayed pH increase, reduced thiobarbituric acid-reactive substances (TBARS) and total volatile basic nitrogen (TVB-N), and improved sensory scores, extending mutton shelf life by over 10 days. Therefore, the ABF effectively inhibited oxidation in MPs, maintained their structural integrity, and preserved mutton quality during super-chilling storage.

Plant cell culture represents a sustainable platform for the production of high-value natural products. Although ultraviolet A (UV-A) radiation is established as an inducer of phenylpropanoid metabolism, its precise regulatory role in downstream flavonoid biosynthesis within grape cells remains unclear. Using red and white-type callus derived from Vitis vinifera L. cv. Cabernet Sauvignon berry skins, we investigated the effects of UV-A treatments with two durations (45 min and 90 min) on flavonoid biosynthesis. Metabolite profiling demonstrated that UV-A predominantly promoted proanthocyanidin accumulation in white-type callus, while stimulating the global flavonoid pathway in a dose-dependent manner in red callus. Transcriptional analysis identified structural genes potentially governing flavonoid product channeling in both callus types under UV-A exposure. Weighted Gene Co-expression Network Analysis (WGCNA) constructed light-responsive regulatory modules, uncovering potential mechanisms coordinating flavonoid pathway gene expression in response to UV-A. These findings demonstrate how the interaction of callus-type and UV-A shapes flavonoid metabolic flux, providing insights into the regulation of plant cell culture metabolites.

In this study, purified Liquidambar formosana Hance melanin (P-LHM) was structurally characterized and evaluated for stability. The yield of P-LHM was approximately 3.47%. Analytical results revealed P-LHM is a melanin-rich complex where eumelanin and pheomelanin polymers are intimately associated with specific flavonoids, phenolic acids, and terpenoids. The condensation molecular formula of P-LHM might be ([C₂₄H₂₉NO₉]_n). The stability evaluation showed that under specific conditions (natural light, darkness, pH = 7–11, 25–100 °C, Na⁺, Al³⁺, Fe²⁺ solution, and low concentrations of reducing agents), the retention rate of P-LHM was >90%. Given its excellent stability, LHM may be used as a new type of food ingredient in the processing of black-colored foods. Meanwhile, the rich phenolic compounds provide a theoretical basis for the development of functional colorants, enhancing the functional value of food colorants.