This study evaluated the effects of different proteases on the extraction, flavor profile, and oxidative stability of blackthroat seaperch (Doederleinia berycoides) liver oil obtained by aqueous enzymatic extraction. Trypsin-assisted extraction yielded oil with the greatest oxidative stability. Combined analysis by gas chromatography-ion mobility spectrometry and gas chromatography-mass spectrometry identified aldehydes as the characteristic volatile compounds in the liver oil. The relative odor activity value analysis identified (E)-2-nonenal, furaneol, benzeneacetaldehyde and 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one as the key volatile compounds. Differences in oxidative stability and thermal behavior were observed among the extraction methods, with the antioxidant capacity of blackthroat seaperch liver oil following the order of pepsin (PS) > alkaline protease > trypsin (TS) > neutral protease extraction methods. Differential scanning calorimetry analysis revealed that PS melting and cooling profiles enhanced flavor release and persistence, while TS and PS exhibited ω-3 fatty acid pyrolysis. These findings demonstrate the importance of enzyme selection for liver oil flavor and stability and support the valorization of blackthroat seaperch by-products.

The aim of this experiment was to investigate the effect of a natural additive Rosa roxburghii Tratt. extraction (RRTE) on the gel properties and flavour of hairtail (Trichiurus lepturus) surimi gels. The effects of different additive concentrations of RRTE on the flavour improvement of hairtail surimi gels were systematically investigated by combining the electronic nose and sensory evaluation techniques. The results showed that the addition of RRTE, especially 2% (m/m) RRTE, could effectively improve the odour score; enhanced the gel strength, water-holding capacity and rheological properties; improved the elasticity, hardness and viscoelasticity of the hairtail surimi gels. The results of water migration and protein secondary structure analysis showed that RRTE could effectively stabilise the internal water distribution of hairtail surimi gels and inhibit protein denaturation. Microstructural observation showed that the gel structure of hairtail surimi in the RRTE added group was more uniform and dense, and the fractal dimension was reduced. The comprehensive results showed that RRTE, as a natural additive, could significantly improve the gel properties and flavour of hairtail surimi gels, providing a scientific basis for the high value-added processing of hairtail surimi products.