Weiqing Sun

Biogenic amines (BAs), produced in fish and seafood due to microbial contamination, pose significant health risks. This study introduces a novel ratiometric fluorescent probe, synthesized by integrating rhodamine 6G(R6G) and gold nanoparticles (AuNCs), for the sensitive and specific detection of BAs. The probe operates on the principle of BAs hydrolysis, catalyzed by diamine oxidase, to produce hydrogen peroxide (H₂O₂), which selectively quenches the fluorescence of AuNCs at 620 nm, while the fluorescence of R6Gat 533 nm remains unaffected. The ratio of I₆₂₀/I₅₅₃ demonstrated excellent linearity with a wide dynamic range (1–1000 μM) and a low detection limit of 0.1 μM. Validation using grass carp samples showed high recovery rates (97.57% to 104.29%), confirming the probe’s efficacy and potential for practical application in food safety monitoring.

Background: Natural myofibrillar protein (MP) is sensitive to changes in the microenvironment, such as pH and ionic strength, and therefore can adversely affect the final quality of meat products. The aim of this study was to modify natural MP as well as to improve its functional properties. Therefore, the quality improvement effect of konjac polysaccharides with different concentrations (0, 1.5, 3, 4.5 and 6 g kg⁻¹ protein) on MP gels was investigated.Results: With a concentration of konjac polysaccharides of 6 g kg⁻¹ protein, the composite gel obtained exhibited a significant improvement of water binding (water holding capacity increased by 7.71%) and textural performance (strength increased from 29.12 to 37.55 N mm, an increase of 8.43 N mm). Meanwhile, konjac polysaccharides could help to form more disulfide bonds and non‐disulfide covalent bonds, which enhanced the crosslinking of MP and maintained the MP gel network structure. Then, with the preservation of α‐helix structure (a significant increase of 8.11%), slower protein aggregation and formation of small aggregates, this supported the formation of a fine and homogeneous network structure and allowed a reduction in water mobility.Conclusion: During the heating process, konjac polysaccharides could absorb the surrounding water and fill the gel system, which resulted in an increase in the water content of the gel network and enhanced the gel‐forming ability of the gel. Meanwhile, konjac polysaccharides might inhibit irregular aggregation of proteins and promote the formation of small aggregates, which in turn form a homogeneous and continuous gel matrix by orderly arrangement. © 2023 Society of Chemical Industry.