冻结方式对莲藕片品质及微观结构的影响

Effect of different freezing methods on the quality and microstructure of lotus root slices

为了研究速冻莲藕片冻结方式对其质地和品质的影响,本研究通过液氮、超低温冰箱和普通冰箱3种冻结方式处理,分析莲藕片质构、自由液滴、维生素C、色泽和微观结构的变化。结果表明:液氮和超低温冰箱冻结属部分玻璃态冻结,普通冰箱冻结为橡胶态冻结。液氮和超低温冰箱冻结的莲藕片细胞结构完整,细胞排列整齐,但速冻仍使部分细胞受损;普通冰箱冻结的莲藕片细胞结构破坏严重,细胞被压扁变形,细胞质溶出,细胞壁降解收缩。超低温冰箱冻结莲藕片品质最佳,莲藕片质构、自由液滴和维生素C损失较少;液氮冻结莲藕片色泽最佳,但会出现冻裂现象;普通冰箱冻结莲藕片汁液流失、品质下降最为严重。表明超低温冰箱冻结是速冻莲藕最佳的冻结方式。

To study the effect of freezing methods on texture and quality of lotus root slices, texture profile, free titer, vitamin C, color and microstructure of lotus root slices by liquid nitrogen freezing, ultra-low temperature freezer freezing and general fridge freezing were analyzed. Liquid nitrogen and ultra-low temperature freezer were partial glassy freezing, while the general fridge was rubbery freezing. Frozen lotus root slices by ultra-low temperature freezer showed less losses of texture, free titer and vitamin C. The color of lotus root slices by liquid nitrogen freezing was the best, but frost occurred. The loss of juice and quality declining was the most severe by general fridge freezing. Cells of fro-zen lotus root slices by liquid nitrogen and ultra-low temperature freezer were structural integrated and lined up, how-ever, some were impacied. Cell structure of lotus root slices by general fridge was damaged seriously; cells were squashed, cytoplasm was dissolved, and cell wall degraded. In conclusion, ultra-low temperature freezer was the best way to cryopreserve lotus root slices.