Novel Ultrasonic Pretreatment for Improving Drying Performance and Physicochemical Properties of <i>Licorice</i> Slices During Radio Frequency Vacuum Drying

To enhance the physicochemical quality, drying efficiency, and nutrient retention of dried <i>Licorice</i> products, this study investigated the effects of ultrasonic pretreatment on the radio frequency vacuum (RFV) drying characteristics, microstructure, and retention of natural active...

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Bibliographic Details
Main Authors: Jun Li, Fangxin Wan, Xiaopeng Huang, Xiaoping Yang, Zepeng Zang, Yanrui Xu, Bowen Wu, Kaikai Zhang, Guojun Ma
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/13/24/4071
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Summary:To enhance the physicochemical quality, drying efficiency, and nutrient retention of dried <i>Licorice</i> products, this study investigated the effects of ultrasonic pretreatment on the radio frequency vacuum (RFV) drying characteristics, microstructure, and retention of natural active substances in <i>Licorice</i> slices. The ultrasonic time, power, and frequency were considered as experimental factors. The results showed that, compared with conventional RFV drying, ultrasonic pretreatment reduced the drying time of <i>Licorice</i> slices by 20–60 min. The Weibull model accurately described the moisture ratio changes under different pretreatment conditions (R<sup>2</sup> > 0.9984, χ<sup>2</sup> < 2.381 × 10<sup>−5</sup>). The optimal retention of polysaccharides, total phenols, total flavonoids, and antioxidants was achieved under pretreatment conditions of 30 min of ultrasonic time, 180 W of ultrasonic power, and 40 kHz of ultrasonic frequency. Furthermore, ultrasonic pretreatment preserved the internal cellular structure of <i>Licorice</i> slices, maintaining intact tissue cells and well-defined microchannels. However, a slight reduction in sample color was observed following ultrasound application. In conclusion, ultrasonic pretreatment significantly improved the RFV drying process for <i>Licorice</i> slices by enhancing drying efficiency, preserving active ingredients, and optimizing the physicochemical quality of the dried product. This study provides novel insights and methods for optimizing the drying process of <i>Licorice</i>, offering a foundation for further research and industrial applications.
ISSN:2304-8158