The role of ultraviolet radiation in the flavor formation during drying processing of Pacific saury (Cololabis saira).

BACKGROUND: Traditional sun-drying aquatic products are popular and recognized by customers, owing to their unique flavor and long-term preservation. However, the product quality and production efficiency cannot be guaranteed. Cololabis saira is rich in unsaturated fatty acids, which are susceptible to hyperoxidation during the drying process. This study aimed to make clear the role of ultraviolet (UV) radiation in flavor formation during drying processes of Cololabis saira to develop a modern drying technology. RESULTS: Lipid oxidation analysis revealed that moderate hydrolytic oxidation occurred in the UV-assisted cold-air drying group due to the combined influence of UV and cold-air circulation, resulting in the thiobarbituric acid reactive substances value being higher than that of cold-air drying group but lower than the natural drying group. Hexanal, heptanal, cis-4-heptenal, octanal, nonanal, (trans,trans)-2,4-heptadienal, (trans,trans)-2,6-nonanedial, 1-octen-3-ol, heptanol, 2,3-pentanedione, 3,5-octadien-2-one and trimethylamine were identified as the characteristic flavor odor-active compounds present in all Cololabis saira samples. Yet, during the natural drying process, sunlight promoted the lipid oxidation, resulting in the highest degree of lipid oxidation among three drying methods. Light and heat promoted lipid oxidation in Cololabis saira prepared through natural drying process, leading to a large accumulation of volatile compounds, such as 3-methylbutyraldehyde, 2,3-pentanedione, 1-propanol, and 3-pentanone. Cold air circulation inhibited lipid oxidation to some extent, resulting in a blander flavor profile. More cis-4-heptenal, cis-2-heptenal, octanal and 2-ethylfuran accumulated during the UV-assisted cold-air drying process, enriching its greasy flavor and burnt flavor. CONCLUSION: UV-assisted cold-air drying could promote moderate lipid oxidation, which is beneficial for improving product flavor. To sum up, UV radiation played a crucial role in the flavor formation during the drying process of Cololabis saira. © 2024 Society of Chemical Industry.

A comprehensive study of the colloidal properties, biocompatibility, and synergistic antioxidant actions of Antarctic krill phospholipids.

Excipient selection is crucial to address the oxidation and solubility challenges of bioactive substances, impacting their safety and efficacy. AKPL, a novel ω-3 polyunsaturated fatty acids (PUFAs) esterified phospholipid derived from Antarctic krill, demonstrates unique antioxidant capabilities and synergistic effects. It exhibits pronounced surface activity and electronegativity at physiological pH, as evidenced by a critical micelle concentration (CMC) of 0.15 g/L and ζ-potential of -49.9 mV. In aqueous environments, AKPL self-assembles into liposomal structures, offering high biocompatibility and promoting cell proliferation. Its polyunsaturated bond-rich structure provides additional oxidation sites, imparting antioxidant properties superior to other phospholipids like DSPC and DOPC. Additionally, AKPL augments the efficacy of lipophilic antioxidants, such as alpha-tocopherol and curcumin, in aqueous media through both intermolecular and intramolecular interactions. In sum, AKPL emerges as an innovative unsaturated phospholipid, offering new strategies for encapsulating and delivering oxygen-sensitive agents.

A facile preparation of FePt-loaded few-layer MoS2 nanosheets nanocomposites (F-MoS2-FePt NCs) and their application for colorimetric detection of H2O2 in living cells.

BACKGROUND: Rapid and sensitive detection of H2O2 especially endogenous H2O2 is of great importance for series of industries including disease diagnosis and therapy. In this work, uniform FePt nanoparticles are successfully anchored onto Few-layer molybdenum disulfide nanosheets (F-MoS2 NSs). The powder X-ray diffraction, transmission electron microscopy, UV-Vis spectra and atomic force microscopy were employed to confirm the structure of the obtained nanocomposites (F-MoS2-FePt NCs). The prepared nanocomposites show efficient peroxidase-like catalytic activities verified by catalyzing the peroxidation substrate 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl (TMB) with the existence of H2O2. RESULTS: The optimal conditions of the constructed colorimetric sensing platform is proved as 35 °C and pH 4.2. Under optimal catalytic conditions, the detection limit for H2O2 detection reaches 2.24 µM and the linear ranger is 8 µM to 300 µM. Furthermore, the proposed colorimetric sensing platform was successfully utilized to detect the intracellular H2O2 of cancer cells (MCF-7). CONCLUSIONS: These findings indicated that the F-MoS2-FePt-TMB-H2O2 system provides a potential sensing platform for hydrogen peroxide monitoring in living cells.