Electrohydrodynamic Drying of Chinese Wolfberry in a Multiple Needle-to-Plate Electrode System.

Jiabao Ni,Yaming Zhang,Xiuzhen Hu,Zhiqing Song,Tingjie Hao,Changjiang Ding

doi:10.3390/foods8050152

Jiabao Ni, Yaming Zhang + Show 4 more

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https://doi.org/10.3390/foods8050152

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Abstract

In order to systematically and comprehensively investigate electrohydrodynamic (EHD) drying characteristics and mechanisms in a multiple needle-to-plate electrode system, drying experiments of Chinese wolfberry were conducted by blocking ionic wind and changing needle spacing in a multiple needle-to-plate electrode system. Drying characteristics, quality parameters, and the microstructure of Chinese wolfberry fruits were measured. Results show that ionic wind plays a very important role during the drying process. Drying rates of different needle spacing treatments are significantly higher than that of the control, and the drying rate decreases with the increase of needle spacing. Needle spacing has a great influence on the speed of ionic wind, rehydration rate, and polysaccharide contents. The effective moisture diffusion coefficient and the electrical conductivity disintegration index decreases with an increase in needle spacing. Ionic wind has a great influence on the effective moisture diffusion coefficient and the electrical conductivity disintegration index of Chinese wolfberry fruits. The microstructure of Chinese wolfberry fruits dried in an EHD system significantly changed. This study provides a theoretical basis and practical guidance for understanding characteristic parameters and mechanisms of EHD drying technology.

Highlights

Chinese wolfberry fruit is widely consumed and has a range of medicinal properties [1,2,3,4,5].Fresh fruits of Chinese wolfberry have a high moisture content and can rot or mildew; they are not suitable for long-term storage
Ionic wind speed decreased with the increase in needle spacing
We found that needle spacing had a greater greater influence on the drying characteristic parameters, the electrical conductivity disintegration influence on the the effective drying characteristic parameters, the electrical disintegration index, index, moisture diffusion coefficient, the and conductivity infrared spectrum characteristic the effective moisture diffusion coefficient, the and infrared spectrum characteristic absorption absorption peak intensity

Summary

Introduction

Chinese wolfberry fruit is widely consumed and has a range of medicinal properties [1,2,3,4,5].Fresh fruits of Chinese wolfberry have a high moisture content and can rot or mildew; they are not suitable for long-term storage. It is very important to dry them in a timely manner. The drying method of Chinese wolfberry mainly includes hot air drying [6], vacuum freeze drying [7], microwave drying [8], and solar drying [9]. Hot air drying and solar drying are easy to operate, but they destroy the effective nutrients in the wolfberry fruit and cause poor drying effect, poor color, and poor flavor quality. The effective nutrients and biological activities of Chinese wolfberry are maintained well using vacuum freeze drying, but the drying equipment is expensive, the operation is complicated, and the energy consumption is high. It is imperative to explore the application of new drying technologies

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Results

Discussion

Conclusion