For example, materials after blanching should be quickly cooled with cold running water, drained with vibratory or centrifugal equipment, frozen with fluidized bed freezer or cold storage, and then dried in vacuum freeze dryer The CFD process technology is characterized by many disadvantages including complicated process steps, large space occupation, huge equipment investment, frequent materials transferring, long drying time, and high production cost [1, 4].
In order to simplify the food FD processes and shorten the drying time, we proposed a novel integrated freeze-drying (NIFD) processing technology based on the principle of vacuum cooling and vacuum freeze dryer [9, 10].
Vacuum Freeze Dryer. In our experiments, the processing steps of the freezing and the freeze-drying of samples were carried out in a laboratory-scale vacuum freeze dryer (SCIENTZ-50F, Ningbo Scientz Biotechnology Co., Ltd., Ningbo, China) which was shown schematically in Figure 1.
In this study, two different freezing methods were carried out in the vacuum freeze dryer: one was the vacuum freezing (VF) performed under vacuum condition and the other one was the plate freezing (PF) performed under atmospheric pressure condition.
Apple slices without HWB pretreatment were put into the vacuum freeze dryer to perform the VF treatment and FD process.
Apple slices were pretreated with HWB and then were quickly transferred into the vacuum freeze dryer to perform the VF treatment and FD process.