Study on the Quality and Energy Consumption of Pulse Spouted Bed Low Frequency Microwave Drying of Cabbage

Abstract:

Hot air drying（AD） of vegetables has many disadvantages including agglomeration，poor quality，high energy consumption and heavy pollutions. In this study，we used cabbage as the raw material，pulse spouted bed low frequency microwave drying（PSBLMD） as the drying method to build a pilot scale research platform. The quality，uniformity and energy consumption of the PSBLMD-dried cabbages were compared with those of the AD-dried ones. Results shown that the amount of ascorbic acid，chlorophyll and the rehydration ratio of PSBLMD-dried cabbages with 15% sugar addition（4.69 mg/hg，3.48 mg/hg and 26.22，respectively） was higher than those of the AD dried cabbages（1.46 mg/hg，3.14 mg/hg and 19.40，respectively）. The uniformity of the products regarding the moisture content，the color appeal and the shrinkage ratio of PSBLMD-dried cabbages were >90%. Compared to AD，PSBLMD not only effectively solved the agglomeration problem during the drying process，but also improved the quality of the dried products. It shortened the drying time by >50% and reduced the energy consumption by >40%.