To elucidate the molecular characteristics and homology of the parvalbumin (PV) gene from Trachinotus ovatus, the full-length cDNA sequence was obtained by gene cloning, and systematic analyses were conducted using bioinformatics approaches. The results showed that the open reading frame of the PV gene was 330 bp in length, encoding 110 amino acids, with a predicted molecular mass of 12.1 kDa and a theoretical isoelectric point (PI) of 4.94. The PV was found to be hydrophilic and thermostable, predominantly composed of typical α-helical structures, belonging to the EF-hand protein family, with potential modification regions and Ca²⁺-binding sites. Sequence alignment revealed that the PV shared 100% homology with the PV sequence of T. anak, indicating a high degree of conservation. This study enriches the database of fish allergens and provides theoretical support for further elucidating their allergenic mechanism and developing hypoallergenic aquatic product processing technologies.

In this study, emulsions containing 30% (m/m) oil phase were prepared using potato starch with different degrees of gelatinization (DSG) and corn oil. The effect of DSG on the stability of the emulsions was evaluated by through measurement of the storage stability, Fourier transform infrared spectra (FTIR), Turbiscan stability index (TSI), particle size, microstructure, and rheological properties. The results showed that the stability of the emulsions initially increased and then decreased with the increase in DSG. As DSG increased up to 67.03%, the characteristic FTIR peaks of water and starch molecules became more pronounced, and the particle size and TSI of the emulsions decreased. This was attributed to an increase in the hydrophobicity of starch and the leaching of amylose following gelatinization, which led to more starch granules participating in the emulsion formation and increased coverage of starch granules on droplets, thereby resulting in smaller droplet sizes and a more stable emulsion. Potato starch with 67.03% DSG resulted in the smallest droplet size and TSI and the best emulsion stability. Increasing DSG (≥ 71.81%) resulted in increased leaching of amylose, leading to chaotic entanglements that hindered the oil phase from integrating into the starch and thereby resulting in larger particle sizes and reduced stability. Moreover, the emulsion containing potato starch with DSG equal to or larger than 64.14% remained stable without any phase separation for 21 days. Laser scanning confocal microscopy (LSCM) observations and rheological analyses of the emulsions showed that the strength of the gel structure was closely correlated to the interaction among oil droplets. Denser arrangement of oil droplets conferred higher apparent viscosity and storage modulus and stronger gel network structure. Additionally, the reduction in the absolute value of the zeta potential of the starch after gelatinization facilitated the proximity of the granules to each other and also increased the strength of the network structure among granules in the continuous phase, thus resulting in improved emulsion stability. This study contributes to a deeper understanding of the mechanism by which gelatinized starch stabilizes emulsions and is of great significance to the development of more stable starch-based emulsions.

The combined effect of ultrasound and high pressure carbon dioxide (HPCD) on the structure and allergenicity of the tropomyosin (TM) of Litopenaeus vannamei was studied. After sequential treatment with ultrasonic at powers up to 2000 W for up to 60 min followed by HPCD at 30 MPa for 15 min, the allergenicity of TM was detected by indirect enzyme-linked immunosorbent assay (iELISA) and Western blot (WB), and the molecular mass was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The spatial structure of TM was characterized by circular dichroism (CD) spectroscopy, fluorescence spectroscopy, ultraviolet (UV) spectroscopy, free amino group and total sulfhydryl group analysis. The results showed that ultrasound at 1500 W for 30 min combined with HPCD decreased the immunobinding activity of immunoglobulin G (IgG) and IgE in TM by 55.3% and 48.7%, respectively, the α-helix relative content decreased to 42.7%, and the secondary structure was changed from an ordered state to a disordered state. The fluorescence spectra showed a blue shift with weakened fluorescence intensity, and the UV spectra exhibited a red shift with enhanced absorption intensity. The free amino group content was reduced by 21.82%, and the total sulfhydryl group content was also reduced. Therefore, ultrasound combined with HPCD treatment changed the spatial conformation of TM, being more effective in reducing the allergenicity than either single treatment.