香蕉片真空冷冻干燥工艺研究

Study on Quick- Freezing of Banana Slice under Vacuum Freeze- Drying Condition

以产品复水率、色差值、含水量和VC含量为指标,采用液氮快速冻结与真空干燥结合技术,对比热风干燥加工方式,进行了香蕉片的真空冷冻干燥研究;着重探讨了工艺参数(物料厚度、搁板温度和真空度)对真空冷冻干燥时间的影响,同时绘制出不同冻结速率下香蕉片的冻结曲线。试验结果表明,从缩短真空冷冻干燥时间和保证产品品质的角度考虑,较优的香蕉片真空冷冻干燥工艺条件为:物料厚度6～8mm,搁板温度43～47.5℃,真空度50～60Pa。

Taking rehydration rate, color value, water content and Vc content of product as main index, compared with hot-air drying, , experimental research of vacuum freeze-drying on banana slices were proceeded with combination technology of liquid nitrogen quick freezing and vacuum freeze-drying. Influence of process paramete~ （material thickness, temperature of heating plate, vacuum degrees） on sublimation time was explored; meanwhile, freezing curve were drew under different freezing rate. The results showed that taking product quality and shortening sublimation time into account, the quick freezing method of bananas, material thickness of 6-8 mm, temperature of heating plate 43-47.5 ℃ , and 50-60 Pa vacuum for drying chamber were advised to be the optimum processing conditions for vacuum freeze-drying bananas.