Multi-dimensional analysis of the effects of drying method on Lipu taro quality characteristics

【Objective】To analyze the quality variability of Lipu taro processed by different drying methods from a multi-dimensional perspective,and to provide theoretical basis for the drying and processing methods of Lipu taro in directional sieving order. 【Method】Lipu taro was used as a test material in strip and slice forms, and four drying methods, namely, hot-air drying, heat-pump drying, vacuum freeze drying and microwave drying, were used to determine the quality characteristics, rheological properties and microstructure, and to compare the drying effect of different drying methods. 【Result】The experimental results showed that microwave drying treatment of Lipu taro in strips had the highest polysaccharide content of 1.178%,while the slices showed the highest polysaccharide content of the vacuum freeze drying treatment, which was 0.976%,and vacuum freeze drying method had small effect on the content of polysaccharides in different material forms. The water content and amylopectin content of Lipu taro with different drying treatments had the same trend,and the water content and amylopectin content of Lipu taro with vacuum freeze drying treatment were the lowest,in which the water content and amylopectin content of taro slices were 4.455% and 1.920 mg/g,and that of taro strips were 3.395% and 2.338 mg/g,respectively. The Lipu taro systems under the four drying treatments all showed typical shear thinning behavior,and the difference in apparent viscosity and shear stress under the same shear rate was large,with the following order from large to small:microwave drying>vacuum freeze drying>heat-pump drying>hot-air drying. The apparent visco-sity of Lipu taro strips increased with the increase of polysaccharide content. Lipu taro powder under vacuum freeze drying treatment microscopically showed smooth and intact spherical particles,while that in the other three drying treatments showed different degrees of breakage and collapse in the structure. 【Conclusion】The water content and amylopectin content of Lipu taro treated by vacuum freeze drying are low, and the original shape of Lipu taro samples can be maintained best, and the drying effect is the optimal.