摘要
采用频率为50、100、150、200和250 Hz、磁场强度为5 mT的交变磁场(AMF)辅助冷冻罗非鱼片，不设磁场(NMF)作为对照组。解冻罗非鱼片的评价包括冻结曲线、质构、显微结构、水分状态和蛋白质结构的评价，随后分析它们之间的相关性。结果表明，在冷冻过程中施加磁场对提高罗非鱼片的综合品质有良好的效果。其中200 Hz效果最好。在此条件下，磁场辅助冷冻罗非鱼片的冷冻时间最短，硬度和弹性下降最小，解冻后咀嚼性最好。冻结过程中产生的冰晶尺寸小且均匀，冻结断面的分形维数最高。肌肉组织损伤最小，保水性提高。磁场辅助冷冻可以维持蛋白质二级结构中的α-螺旋和p-片。相关分析表明，磁场处理后罗非鱼片的内聚力、弹性、分维、FD、a2、A_(22和p-turn与鱼片品质变化密切相关。
Abstract
In this study, the alternating magnetic field (AMF) with frequency of 50, 100, 150, 200 and 250 Hz at magnetic field intensity of 5 mT was used to assist the freezing of tilapia fillets, with no magnetic field (NMF) as a control group. The evaluation of thawed tilapia fillets encompassed an assessment of freezing curve, texture, microstructure, moisture state and protein structure, followed by a subsequent analysis of their correlation. The findings showed that the application of a magnetic field during the freezing process yielded favourable outcomes in enhancing the overall quality of tilapia fillets. Among them, 200 Hz had the best effect. Under the condition, the frozen tilapia fillets assisted by magnetic field showed the shortest freezing time, the least decrease in hardness and elasticity and the best chewiness after thawing. The size of the ice crystals generated during freezing was small and uniform, and the fractal dimension of the frozen sections was the highest. Muscle tissue was the least damaged, which led to the improvement of its water-holding capacity. Magnetic field-assisted freezing was found to maintain the α-helix and P-sheet in the secondary structure of proteins. The correlation analysis showed that cohesion, elasticity, fractal dimension, FD, A_2, A_(22) and P-turn were closely related to the quality changes of tilapia fillets after magnetic field treatment.
NETL
NSTL
Wiley