冷冻是一种常见的食品保存方法,但传统冷冻技术会形成大量不规则的冰晶,影响水产品口感和营养价值.建立了一个基于冲击式速冻机的静磁场辅助冷冻系统,旨在提升冷冻品质,减小冻结过程对水产品的不利影响.实验研究了不同强度(0、20、40、60、80 Gs)的静磁场(Static magnetic field)对冷冻竹节虾(Penaeus japonicus)水分分布和理化性质的影响.结果显示,静磁场辅助冷冻技术缩短了相变时间,磁场强度越大,相变时间越短.磁场辅助冷冻技术还显著地减小了解冻损失、蒸煮损失和离心损失.其中SMF-80组蒸煮损失和离心损失与新鲜组并无显著性差异,表明磁场辅助冷冻能够有效减小竹节虾水分损失.低场核磁共振显示施加静磁场后,固定水和自由水的迁移和损失降低了.静磁场加快冷冻速率,抑制了虾样品L*值的增加,DSC分析显示竹节虾蛋白质热稳定性增加,表明施加静磁场能够减小对蛋白质结构的破坏.静磁场辅助冷冻技术改善了冻融过后竹节虾的硬度、咀嚼性和弹性,提升了竹节虾的口感.综上,静磁场辅助冻结系统有效改善了冷冻竹节虾的品质,减小了冷冻过程对竹节虾口感和营养价值的不利影响.
Effect of static magnetic field-assisted freezing on the quality of frozen Penaeus japonicus
Freezing is a common method of food preservation,but the traditional freezing method causes the formation of a large number of irregular ice crystals,which affects the taste and nutritional value of aquatic products.In this study,a static magnetic field-assisted freezing system based on an impact freezer was established to improve the freezing quality and reduce the adverse effects of freezing on aquatic products.The effects of static magnetic fields with different intensities(20 Gs,40 Gs,60 Gs,and 80 Gs)on the moisture distribution and physicochemical properties of frozen Penaeus japonicus were investigated.The results showed that the static magnetic field-assisted freezing technique shortened the phase transition time,and the higher the magnetic field intensity,the shorter the phase transition time.In terms of moisture distribution,the magnetic field-assisted freezing technique significantly reduced the thawing loss,cooking loss,and centrifugal loss.Among them,the cooking loss and centrifugal loss of the SMF-80 group were not significantly different from those of the fresh group,indicating that the magnetic field-assisted freezing can effectively reduce moisture loss of Penaeus japonicus.LF-NMR showed that the static magnetic field reduced the mobility and loss of fixed and free water.In addition,the static magnetic field accelerated the freezing rate and suppressed the increase of L*value in shrimp samples,and the DSC analysis showed that the thermal stability of of Penaeus japonicus proteins increased,indicating that the application of static magnetic field could reduce the damage to the protein structure.The static magnetic field also significantly improved the hardness,chewiness and resilience of Penaeus japonicus after freezing and thawing,and enhanced the texture of Penaeus japonicus.In conclusion,the static magnetic field-assisted freezing system effectively improved the quality of frozen Penaeus japonicus and minimized the adverse effects of freezing on the nutritional value of Penaeus japonicus.
Penaeus japonicusstatic magnetic fieldfreezing curvewater holding capacitywater distribution
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