Qian Ning,Zhen Guo,Qinhua Zhang,Wanxin Hong,Huiyue Zhang,Yilan Sun,Jie Pang
The persistent fishy odor in kelp ( Laminaria japonica ) has significantly hindered its industrial applications. Although biofermentation serves as a common deodorization method, its non-reusable nature remains a notable limitation. This study investigated the precise degradation kinetics of key fishy compounds in kelp by a yeast immobilization system during five consecutive fermentation rounds. Under optimized conditions (3.8 h, 33°C, yeast inoculation 0.58 g/kg) in the immobilization system, the first round of kelp fermentation (KF1) achieved a sensory score of 90.3. Scanning electron microscopy (SEM) results indicated that the structural integrity of the yeast and the fiber membrane remained well-preserved during the first three cycles. However, a progressive flattening of both the yeast and the membrane structure was observed after the fourth and fifth cycles. Gas Chromatography-Mass Spectrometry/Odor Activity Value (GC-MS/OAV) analysis revealed that after the first fermentation round, the OAVs of critical fishy compounds 1-octen-3-one and ( E )-2-nonenal decreased significantly by 69.43% and 72.55%, respectively. Even after five round of kelp fermentation (KF5), their OAVs remained low, showing sustained reductions of 31.12% and 69.58% compared to the unfermented (UF) control. Further Partial Least Squares Discriminant Analysis (PLS-DA) identified 1-octen-3-one, ( E )-2-nonenal, and decanal as key fishy markers. These results demonstrate that the immobilization system maintains efficient multi-cycle deodorization, significantly reducing the contribution of key fishy compounds, thereby providing a critical foundation for developing recyclable and stable kelp processing technologies.
Lin Zhang,Xinyao Wang,Haiyang Zhang,Fei Pan,Yuanyuan Liu,Xuanpeng Wang,Xianbing Xu,Jinfeng Pan
This study investigated the effects of three enzymolysis strategies, alcalase, neutrase, and acid protease in combination with flavourzyme (AF, NF and CF) on the flavor properties of skipjack tuna ( Katsuwonus pelamis ) head. The effects of three deodorization methods, yeast (y), activated carbon (a) and β-cyclodextrin (β) on the hydrolysate properties were also studied. The hydrolysis degree (45.23 ± 2.25 %) and protein recovery (71 ± 3.5 %) of AF were the highest. Sensory evaluation and volatile compound analysis reveal that AF possessed favorable taste and flavor characteristics. Yeast, activated carbon and β-cyclodextrin significantly improved the flavor profile of hydrolysate. Gas chromatography mass spectrometry analyses indicate that yeast effectively reduced the concentrations of octanal and nonanal by 63 ± 0.34 % and 47 ± 0.02 %, while promoting the formation of the aromatic compounds 1-nonanol (0.87 ± 0.01 mg/L) and phenylethyl alcohol (0.62 ± 0.06 mg/L). Moreover, yeast resulted in 77.6 % ± 1.05 increase in umami-amino acids and 19 ± 0.94 % decrease in bitter-amino acids in NF-y. Thus, enzymolysis strategy by alcalase or neutrase with flavourzyme coupled with deodorizing strategy by yeast could be applied for producing value-added hydrolysate from skipjack tuna head.
危险品化学品经营许可证（带存储）