不同冻结温度对山药片营养品质的影响

目的]研究不同冻结温度对山药片营养品质变化的影响,为速冻山药产品的加工提供理论指导。方法]将山药片分别在不同速冻温度(-20、-25、-30、-35℃)下进行速冻,研究速冻前后山药细胞结构、质构、维生素C含量和失水率的变化。结果]不同冻结温度对山药片细胞破坏程度不同。-20和-25℃冻结的山药片,其细胞内形成的冰晶较大,破坏了细胞的结构,解冻后细胞形态受破坏;-35℃冻结的山药,冻结速度较快,形成的冰晶小,对细胞结构的破坏较小。解冻后产品不仅硬度损失少,而且维生素C的损失以及失水率都最小,营养品质变化也最少。结论]-30℃速冻是冻结山药片较适宜的温度。

Effects of Different Freezing Temperatures on the Nutritional Quality of Yam Slices

Objective] The purpose was to study the effects of different freezing temperatures on the nutritional quality change of yam slices so as to provide theoretical guidance for processing quick frozen yam products.Method] The yam slices were quickly frozen under different quick freezing temperatures(-20,-25,-30 and-35 ℃) so as to study the changes of cell structure,texture,vitamin C content and water losing rate in yams before and after quick freezing.Result] The destroy degrees of different freezing temperatures on the cells in yam slices were different.In the yam slices frozen at-20 and-25 ℃,the ice crystal formed in the cell was bigger,which destroyed the cell structure,and then the cell shape was destroyed after thawing.In the yam frozen at-35 ℃,the freezing speed was faster and the formed crystal was smaller,which destroyed the cell structure less.The thawed product not only had less hardness loss,but also had least vitamin C loss and water losing rate,and its change of nutritional quality was least.Conclusion]-30 ℃ was more suitable temperature for freezing yam slices in their quick freezing.