Smart use of different drying technologies to process polyphenols-containing plants: Progresses, challenges and application prospects

Plants are important sources of bioactive compounds, including polyphenols. Since drying is in many cases required when processing polyphenols-containing plants, a means to reduce losses of bioactive compounds and to improve the nutritional quality of dried products is highly desirable. Although several reviews on different aspects of drying have been published, there is no available critical evaluation on the use of different drying techniques to maintain phenolic compounds in dried polyphenols-containing plants. Suggestions on future applications of novel drying techniques to achieve the aforementioned goal are in particular lacking. The present review therefore aims to first summarize the types of polyphenols-containing plants and related products. Possible smart use of different drying and pretreatment techniques for efficient processing of polyphenolscontaining plants is then critically reviewed. Future application directions of novel drying technologies for processing polyphenols-containing plants are finally discussed.