The Effect of Material Thickness, Load Density, External Airflow, and Relative Humidity on the Drying Efficiency and Quality of EHD-Dried Apples

Effect of electrohydrodynamic (EHD) drying on active ingredients, textural properties and moisture distribution of yam (Dioscorea opposita)

This paper systematically investigates the changes in material properties during electrohydrodynamic (EHD) drying, the discharge characteristics of the EHD system as well as the active ingredients, textural properties (hardness, adhesiveness, etc.) and moisture distribution of yam under EHD, air drying and hot air drying were investigated. The results showed that the active particles and the ionized wind generated during the discharge process of the electrohydrodynamic drying device had a significant effect on the drying. Compared to thermal drying, 21 kV drying resulted in the most complete cellular structure, the best internal bound water content as well as textural properties of yam. It played a positive role in the retention of internal nutrients in yam, and the total phenol and allantoin contents were increased by 25.74% and 81.99%, respectively. These results elucidate the advantages of electrohydrodynamic drying in yam drying and provide a reference for the application of EHD in drying.

Influence of electrohydrodynamics on the drying characteristics and volatile components of iron stick yam

The drying characteristics, rehydration capacity, color, infrared spectra and volatile components of iron stick yam slices were investigated under different alternating current (AC) voltages (13, 17, 21 kV), hot air drying (HAD) (60 °C) and natural drying (AD) by electrohydrodynamic (EHD) drying and HAD experimental devices. The results showed that slices of iron stick yam dried the quickest with HAD, which also had the fastest drying rate; while drying the slices of iron stick yam with EHD led to a better rehydration capacity, higher brightness L* and whiteness, a more stable protein secondary structure, and a greater variety and content of volatile components compared with AD and HAD. These finding indicated that EHD is a more promising method for drying iron stick yam.

Effect of Electrohydrodynamic Drying on Drying Characteristics and Physicochemical Properties of Carrot

This study investigates the effects of electrohydrodynamic (EHD) drying technology on the drying kinetics, microstructure, quality, and nutritional components of carrots, along with conducting experiments on EHD drying under different voltage gradients. The experimental results showed that EHD drying technology could significantly increase the drying rate and the effective moisture diffusion coefficient. Within a certain range, the drying rate was directly proportional to the voltage. When the range was exceeded, the increase in voltage had a minimal effect on the drying rate. In terms of quality, the EHD drying group's color, shrinkage rate, and rehydration performance were superior to the control group, and different voltages had no significant effect on the shrinkage rate and rehydration performance. The retention of carotenoids in the EHD drying group was 1.58 to 2 times that of the control group. EHD drying had a negative impact on the total phenolic content and vitamin A content of dried carrot slices. Based on the results of infrared spectroscopy and scanning electron microscopy (SEM), the dehydrated carrot slices showed wrinkling due to water loss, with numerous pores, a generally intact structure, and retained functional groups. EHD drying had a significant impact on the secondary structure of proteins, where an increase in voltage led to an increase in disordered structure, with a smaller proportion of disordered structure in the lower voltage group compared to the control group, and a similar proportion of disordered structure between the higher voltage group and the control group. Results from low-field nuclear magnetic resonance (NMR) showed that EHD drying could retain more bound water compared to the control group, with the best retention of cellular bound water at a voltage of 26 kV and the best retention of cellular immobilized water at a voltage of 38 kV, indicating the superiority of EHD drying in preserving cellular structure. This study provided a theoretical basis and experimental foundation for the application of electrohydrodynamic drying technology to carrot drying, and promoted the practical application of EHD drying technology.

Predicting the Moisture Ratio of a Hami Melon Drying Process Using Image Processing Technology

For food drying, moisture content and shrinkage are vital in the drying process. This paper is concerned with the moisture ratio modeling and prediction issues of the Hami melon drying process. First, an experimental system was developed; it included an adjustable-power microwave drying unit and an image-processing unit. The moisture contents and the areas of Hami melon slices at different times were sampled in real time. Then, the expression of the moisture ratio with regard to shrinkage was derived by using the Weierstrass approximation theorem. A maximum likelihood fitness function-based population evolution (MLFF-PE) algorithm was then put forward to fit the moisture ratio model and predict the moisture ratio. The results showed that the proposed MLFF-PE algorithm was effective at fitting and predicting the moisture ratio model of the drying process of Hami melon slices.